Issue 229: the stale tool list is a connection opened before discovery; the fix is list-changed

Issue 230: a report is also lost when the apply restarts the bus
Issue 229: new tools never reach an agent's connection, and the console's generic tools are not on it
2026-10-04 11:01:50 +02:00 · 2026-10-04 11:00:27 +02:00 · 2026-10-04 11:00:13 +02:00 · 2026-10-04 10:54:35 +02:00 · 2026-10-04 10:51:45 +02:00 · 2026-10-04 08:49:36 +00:00
26 changed files with 1709 additions and 22 deletions
@@ -0,0 +1,152 @@
+---
+status: graduated
+initiated: 2026-10-04
+touches: [the bus, what a module declares, the tool runtime, the SDK, the bus grants, 03-DESIGN/01-to-be/25-the-bus-on-nats.md, 03-DESIGN/01-to-be/32-what-a-module-declares.md]
+became: [02-DECISIONS/0201-a-module-keeps-its-current-state-in-key-value-buckets-it-declares-and-reaches-through-the-runtime.md, 03-DESIGN/01-to-be/32-what-a-module-declares.md, 03-DESIGN/01-to-be/25-the-bus-on-nats.md]
+---
+
+# 024 — State a module keeps on the bus
+
+## What is investigated
+
+A place on the bus where a module's own code keeps **current state** — not history — that every
+machine sees, including a machine that joins after the state was written: put, get, delete, list and
+watch, reached through the node's runtime the way a bundle already publishes, asks and subscribes
+([ADR 0198](../../02-DECISIONS/0198-a-modules-long-running-code-is-launched-by-the-node-runtime-and-reaches-the-bus-through-it.md)).
+On NATS that is a key-value bucket. The questions are what a module declares, who creates the
+bucket, what the grants are, what the runtime's verbs are, and what may never be stored.
+
+## Why
+
+The mesh carries two kinds of module traffic and a third is missing.
+
+- **Events** land in the EVENTS stream: limits retention, seven days, ten thousand messages per
+  subject, a durable consumer per consuming module that replays what it missed. Never a secret
+  ([design 32](../../03-DESIGN/01-to-be/32-what-a-module-declares.md) §10).
+- **Requests** are core request/reply — tool calls, a bundle's `mesh/ask` — and are kept nowhere.
+
+Neither is *the current value of something*. Two cases from the first module that needs it, the
+operator's agent on a machine ([design 36](../../03-DESIGN/01-to-be/36-the-operators-agent-on-a-machine.md)):
+
+1. **An MCP server registered for every machine.** Registering emits an event every machine's copy
+   of the module consumes. A machine the module is assigned to *after* the registration has no
+   durable consumer yet — the consumer is created at assignment — so it never hears of it. Wanted
+   instead: one entry per server, for every machine or for one; every machine reads the whole current
+   set when it starts and watches for changes; unregistering is a delete; any machine can list it.
+2. **Which licence a machine is bound to** ([design 39](../../03-DESIGN/01-to-be/39-the-anthropic-licence-manager.md)).
+   As events, a machine that was off for a day replays every rotation since and asks for a token
+   after each. It needs only the latest binding and its generation. The token itself stays on
+   request/reply and is never stored.
+
+The design already expects this. [Design 25](../../03-DESIGN/01-to-be/25-the-bus-on-nats.md) §1:
+"conditions and observed state in key-value buckets that anything may watch".
+[Research 017](../017-a-mesh-that-heals-itself/01-the-intended-behaviour.md) wants a provisioner's
+"what I applied" and a rotation's step kept in one rather than in memory. Nothing implements it.
+
+## What exists, measured 2026-10-04
+
+| | fact | where |
+|---|---|---|
+| streams | five kinds of mesh stream: CONTROL (work queue), NODES and ASSIGNMENTS (last per subject), EVENTS (limits: 7 days, 10 000 per subject), one work queue per seat that accepts | the controller's broker streams |
+| the state relationship | [design 32](../../03-DESIGN/01-to-be/32-what-a-module-declares.md) §4 already names *state* — 1:1, last per subject — and says it is "declared: the mesh's own". Two streams use it, both written by the controller. No module can declare it | design 32, the controller |
+| key-value buckets | none, anywhere | all four code repositories |
+| the runtime's bus verbs | `mesh/publish`, `mesh/ask`, `mesh/subscribe`; delivery back to the bundle is `mesh/event` | the runtime's launcher |
+| the runtime's principal | one bus user per machine carries every assigned module; its grant is the union of theirs. That one module's code does not act as another is the runtime's to keep: it publishes under the module's own name by construction | the controller's grant composition, the runtime's bus |
+| what a bundle is issued | a membership per assignment, last per subject, read directly by the runtime: where it serves, where it emits, what it reaches | ADR 0160 |
+| who creates bus objects | the controller only — mesh streams on every raise, a seat's stream at registration, a module's consumer at assignment. No module reaches the JetStream API | design 25 §3 |
+
+### What a key-value bucket needs from a grant, against a real server
+
+Measured against nats-server 2.10 with the Go client the runtime already uses, a bucket created by
+an unrestricted user and used by two users holding only the subjects below (`B` is the bucket):
+
+| operation | subject published | writer | reader |
+|---|---|---|---|
+| bind to the bucket | `$JS.API.STREAM.INFO.KV_B` | yes | yes |
+| get | `$JS.API.DIRECT.GET.KV_B.>` | yes | yes |
+| put, delete | `$KV.B.>` | yes | **refused** |
+| list keys, watch | `$JS.API.CONSUMER.CREATE.KV_B.>` — an ordered, ephemeral consumer | yes | yes |
+| stop a watch cleanly | `$JS.API.CONSUMER.DELETE.KV_B.>` | yes | yes |
+| answers | its own inbox, which every principal already subscribes | — | — |
+
+*Checked again once built, 2026-10-04:* the grants the controller composes for two machines' runtimes —
+one carrying the owner, one only a reader — were loaded into a server as composed, and each operation
+was run as each runtime's user. The owner's did all of them; the reader's read, listed and watched,
+and its put and delete were refused by the server.
+
+Three things the measurement showed that reading the documentation would not have:
+
+1. **A refused put is not an error to the caller; it is a timeout.** The server reports the
+   permission violation asynchronously, on the connection, and the client waits out its deadline
+   for an acknowledgement that never comes. So a runtime that relies on the grant alone tells a
+   bundle "timed out" for "you may not write this" — it must refuse first, from what the module was
+   issued, with the reason.
+2. **A watch's current values include deletions.** A key deleted earlier arrives among the initial
+   values as a delete marker, before the end-of-current marker. A bundle asking "what is there now"
+   must not be handed those.
+3. **Without the consumer-delete grant, stopping a watch hangs** until its deadline, and the
+   ephemeral consumer lingers on the server until it times out by itself.
+
+### Whether the events shape is enough instead
+
+Honestly compared, because a new primitive is a cost:
+
+- **EVENTS cannot be made last-per-subject for some subjects.** Retention is per stream, and
+  JetStream refuses a second stream overlapping the first (verified and recorded in design 32 §3).
+  A state subject inside `mesh.mod.*.event.>` keeps EVENTS' seven days: a licence binding unchanged
+  for a week disappears.
+- **A separate last-per-subject stream per module** is possible — it is exactly what a key-value
+  bucket *is* on the server: a stream with one message per subject, a rollup for purge, and direct
+  reads. Building it by hand gives up the client's get, list, delete and watch, which are the
+  operations both cases need, and would be the mesh writing NATS's own key-value layer again.
+- **Consumers are the wrong reader.** A durable consumer per reading module is created at
+  assignment and replays from where it is; state wants "everything current, now, then changes",
+  which an ordered ephemeral consumer from the last value per subject gives and a durable does not.
+
+So key-value is not a convenience over events; it is the state relationship design 32 already
+names, opened to modules.
+
+## Questions, and what this effort proposes
+
+1. **What a manifest says.** `state` names the buckets a module owns, by local name — every
+   instance of the module may write them and read them. `reads` names another module's bucket as
+   `<module>.<name>`, read-only. Names only, never a bucket or subject (design 32 §1). A bucket's
+   options — how many past values it keeps, how long a value lives — are the owner's to declare,
+   the way a seat declares its own retention (design 32 §3).
+2. **Scope.** One bucket per module per name, mesh-wide. A key may carry a machine by the module's
+   own convention (`all.<server>`, `<machine>.<server>`). A bucket per machine was considered and
+   not proposed: "list every server for every machine" becomes a walk over buckets, and the grant
+   could only narrow writes, which nothing asked for — every instance of the owner already writes.
+3. **Who creates the bucket.** The controller, from the catalogue, on every raise — a bucket exists
+   from registration, like a seat's stream, so a reader can watch before the owner is assigned
+   anywhere. Never a module.
+4. **The runtime's verbs.** `mesh/state.get`, `mesh/state.put`, `mesh/state.delete`,
+   `mesh/state.keys`, `mesh/state.watch`, each naming the bucket as the module named it. A watch
+   is answered once the current values are on their way, then each change is delivered to the
+   bundle as a `mesh/state` request it answers — current values first (no deletions among them), an
+   end-of-current marker, then changes. A child that restarts watches again, as it subscribes
+   again. The runtime refuses, with the reason, a bucket the module was not issued, and a write to
+   one it only reads.
+5. **Secrets.** None in a bucket, sealed or not: a bucket is a stream (design 32 §10). Sealed values
+   are plain base64 and cannot be recognised, so the mechanical check is partial and said to be: the
+   runtime refuses a value carrying a field whose name says it is a credential (`password`,
+   `secret`, `token`, `authorization`, …), which catches the ordinary mistake and not a determined
+   one. For the first consumer this has a concrete consequence: an MCP server registered with an
+   authorisation header keeps that header out of the bucket.
+6. **History, lifetime, size.** One value per key unless the owner says more; no expiry unless it
+   says one; a value at most 256 KiB and a bucket at most 64 MiB, the mesh's caps rather than a
+   module's. **A bucket outlives its module's assignment** — what a module stored is data, and data
+   outlives what declared it ([ADR 0030](../../02-DECISIONS/0030-data-outlives-the-mesh-that-declared-it.md));
+   unassigning is not cleaning up. A bucket whose declaration is gone is reported, never removed.
+7. **Events or state.** State (above).
+
+## The work, once decided
+
+1. A decision record, then design 32 (*state* becomes a relationship a module declares) and design
+   25 (key-value buckets are part of the bus) amended.
+2. The controller: the manifest's two words and their registration check; buckets asserted on every
+   raise; the grants for owners' and readers' runtimes; the buckets issued in each membership.
+3. The runtime: the five verbs, the watch delivery, the refusals; tested against a real server.
+4. The SDK, TypeScript and Go: a small state surface over the verbs.
+5. Proved on a running mesh with one small module, then handed to the operator's agent, whose
+   registered servers move from events to a bucket.
@@ -0,0 +1,94 @@
+---
+status: graduated
+initiated: 2026-10-04
+touches:
+  - 02-DECISIONS/0174-a-node-varies-a-module-through-settings-and-kept-regions-never-an-edit.md
+  - 02-DECISIONS/0176-the-login-shell-is-a-node-seat-and-execute-is-its-contract.md
+  - 02-DECISIONS/0177-a-unit-may-be-user-scoped-and-the-service-manager-is-a-node-seat.md
+  - 02-DECISIONS/0126-a-module-declares-its-own-seats.md
+  - 02-DECISIONS/0102-the-mesh-writes-into-a-shared-file-never-over-it.md
+  - 02-DECISIONS/0182-inside-a-home-the-mesh-owns-what-it-places-and-holds-the-rest-as-found.md
+  - 02-DECISIONS/0112-a-module-definition-names-no-node-mesh-or-path.md
+  - 03-DESIGN/01-to-be/27-a-module-requires-the-mesh-resolves.md
+  - 03-DESIGN/01-to-be/31-a-module-declares-its-fail2ban-jail.md
+  - 03-DESIGN/01-to-be/37-the-operators-machine.md
+  - 03-DESIGN/01-to-be/38-building-the-operators-machine.md
+  - 04-ISSUES/168-a-setting-reaches-every-file-and-contribution/00-report.md
+became:
+  - 02-DECISIONS/0203-the-accounts-environment-is-one-modules-and-every-module-contributes-to-it.md
+  - 02-DECISIONS/0204-a-module-contributes-shell-code-to-the-login-shell-in-named-slots.md
+  - 02-DECISIONS/0205-software-the-distribution-does-not-package-ships-as-a-pinned-archive-of-the-module.md
+  - 03-DESIGN/01-to-be/41-the-shell-and-the-accounts-environment.md
+---
+
+# 025 — How a module plugs into the operator's shell
+
+## What is investigated
+
+The shell module writes the mesh's part of the account's shell startup file. But the shell is not the
+only module that needs a line there. A prompt theme loads itself from it. A language version manager
+sets a variable and sources its loader. A toolchain puts its directory on `PATH`. A desktop module
+names the browser. Today all of these sit in one hand-written file, and the shell module as written
+carries some of them in its own block and loads others only "if a module placed them". Nothing says
+how they get placed.
+
+This effort asks four things:
+
+1. **How a module contributes to the shell**: what it declares, who composes it, and in what order it
+   lands.
+2. **Where the environment lives.** Variables and `PATH` entries are facts about the account, not
+   lines of one shell's syntax. They should reach every shell (interactive or not), the login shell's
+   `execute` verb, and programs a graphical session starts.
+3. **Where the operator's own lines go,** so that assigning the shell module loses nothing the
+   machine does today.
+4. **Which part of a file the mesh owns.** ADR 0174 calls the kept region the operator's; the host and
+   to-be 38 implement the inverse (the mesh owns a marked block, and everything outside it is the
+   operator's). The record this becomes says which.
+
+## Why
+
+Rolling out the shell module (to-be 38 WP5) was stopped on 2026-10-04 after a review of what assigning
+it would do. Measured in [01](01-what-the-shell-file-holds-today.md):
+
+- Every machine carries the same predecessor-written startup file, so the module's block would be
+  appended after its own older copy and everything would run twice.
+- The block drops lines the machines rely on today.
+- Nothing installs the prompt theme or the plugins the block loads.
+- The `execute` verb runs a non-interactive login shell, which never reads the file the block is
+  written into.
+
+The operator's direction: other modules must be able to plug themselves into the shell; the prompt
+becomes its own module; assigning the shell module must lose no functionality; and the environment,
+`PATH` above all, needs an answer of its own.
+
+## What it touches
+
+- The manifest. A contribution to the shell is either a new use of the existing `contributes` /
+  `receives` pair or a new gathered field like `jails` (to-be 31).
+- The controller's composition, if the controller assembles the text.
+- The `login-shell` seat (ADR 0176): what a holder must do with what is contributed to it, and
+  whether a module or the mesh declares the seat. Possibly a new seat for the environment, beside it
+  and beside the service manager's (ADR 0177). Research 023 asks the related question of a seat
+  naming the files its holder owns.
+- ADR 0174's wording of the kept region, and ADR 0182's classification of the paths under a home.
+- The zsh module, and the modules this makes possible: an environment module, the prompt, a version
+  manager, a toolchain.
+
+## Where it stands
+
+The operator proposed a separate **environment module**: one module, holding a mesh seat of its own,
+that alone writes the account's environment. It writes a file that shells source and the service
+manager's user environment, from the variables and `PATH` entries every other module contributes to
+it. That is the starting position for the environment ([02](02-how-a-module-plugs-in.md) §1, option
+E6). It leaves the shell's contribution as shell code only (§2), addressed to the `login-shell` seat,
+which moves into the mesh's own seat set beside the new `node-environment` (§6).
+
+Graduated on 2026-10-04 with one change from the starting positions: the controller, not the
+environment module's own code, renders the environment into the module's files, so that the result
+is in the declaration before a machine applies it ([ADR 0203](../../02-DECISIONS/0203-the-accounts-environment-is-one-modules-and-every-module-contributes-to-it.md),
+option 6b).
+
+## Documents
+
+- [01 — What the shell file holds today](01-what-the-shell-file-holds-today.md): evidence.
+- [02 — How a module plugs in](02-how-a-module-plugs-in.md): the options and the starting position.
@@ -0,0 +1,103 @@
+# 01 — What the shell file holds today
+
+Measured 2026-10-04 on the four machines of one installation: two servers and two workstations. All
+four have the account's login shell set to zsh, zsh installed from the distribution, and a
+predecessor-written startup file. The predecessor is retired, so nothing manages these files any more.
+
+## The startup file is the same everywhere
+
+The account's `~/.zshrc` is **byte-identical on all four machines**: 102 lines, one checksum.
+`~/.zshrc.local`, which the last line of `~/.zshrc` sources, comes in **two variants**: one shared by
+both servers, and one shared by both workstations. So the "per-machine" part is really a
+per-*kind*-of-machine part.
+
+The predecessor produced these from one module with two *flavors*: a prompt flavor and an
+autocomplete flavor, each of which swapped in a different local file. Its install hook also:
+
+- cloned the prompt theme and three plugins from their upstream repositories into `~/.zsh/`;
+- installed fonts;
+- changed the login shell.
+
+On the workstations the theme and plugins are still on disk, left over and now owned by nothing. The
+servers have none of them.
+
+## What the 102 lines are
+
+Sorted by who should own each line once the machine is modules:
+
+| Lines today | What they are | Natural owner |
+|---|---|---|
+| `EDITOR`, `VISUAL`, `XDG_CONFIG_HOME`, `PATH` gaining `~/.local/bin` and two script directories | the account's environment | the shell's default, or the environment itself |
+| `PATH` gaining a toolchain's directory | environment, for one tool | the toolchain's module |
+| a version manager's directory variable plus sourcing its loader | environment *and* shell code | the version manager's module |
+| two variables naming the operator's own script library | environment, the operator's own | the operator |
+| a variable that turns off an agent's terminal-title handling | environment, for one tool | the agent's module |
+| the terminal title hook, keybindings, `dircolors`, the `ls`/`grep` aliases, `ll`/`la`/`l`, a container-run alias, two disk-usage functions, two port aliases | interactive shell behaviour | the shell's default |
+| the prompt's instant-prompt cache, the theme, the prompt's own configuration file | shell code, order-sensitive (instant prompt first) | the prompt module |
+| autosuggestions, syntax highlighting (and, unloaded, an autocomplete plugin on disk) | shell code, order-sensitive (syntax highlighting last) | a plugin module, or the prompt module |
+| sourcing `~/.zshrc.local` | the operator's hook | the operator |
+
+The workstation variant of the local file adds:
+
+- more environment: a desktop toolkit theme, a file manager's plugin list, `BROWSER`, `VISUAL`
+  overridden to a graphical editor, a language toolchain's binary directory on `PATH`;
+- two pieces of shell code: one that pads the prompt to the bottom of the terminal under a display, and
+  one that sources a function file another module places;
+- a hook sourcing a further per-node file.
+
+The server variant holds only that last module-placed source line.
+
+**Count:** a workstation runs 65 non-comment lines from the two files (53 shared, 12 local); a server
+runs 54. Of a workstation's 65:
+
+- about a quarter (15) are environment;
+- about half are interactive defaults no other module cares about;
+- the remaining quarter is other modules' code and hooks (a prompt, plugins, a version manager, an
+  agent's functions), loaded from the shell file only because there was nowhere else to put it.
+
+## The shell module as written
+
+The `zsh` module of to-be 38 WP5 (catalogue change, unmerged):
+
+- writes one block, appended at the end of `~/.zshrc`, holding a subset of the shared file:
+  - its environment lines, minus the toolchain directory, the version manager and the agent variable;
+  - the title hook, keybindings and the most common aliases, minus the port aliases;
+  - guarded `source` lines for the theme and two plugins *if present*;
+  - the source of `~/.zshrc.local`.
+- assigned to any of the four machines, appends that block after the identical lines already there, so
+  every line in it runs twice, `~/.zshrc.local` included.
+- on the servers, the guarded prompt lines find nothing; nothing installs the theme anywhere.
+
+## Which startup file reaches what
+
+zsh's startup order, and what each path through it reads:
+
+| started as | reads |
+|---|---|
+| interactive login (a console, ssh with a terminal) | `.zshenv`, `.zprofile`, `.zshrc`, `.zlogin` |
+| interactive non-login (a new terminal window) | `.zshenv`, `.zshrc` |
+| non-interactive login: `zsh -lc …`, what the `execute` verb runs | `.zshenv`, `.zprofile`, `.zlogin`, **not** `.zshrc` |
+| non-interactive: a script, `ssh host command` | `.zshenv` only |
+
+So an environment written into `.zshrc` reaches neither `execute` nor a script. The distribution's
+system-wide login profile, which zsh's system `zprofile` sources, only ever *appends* to `PATH` when an
+entry is missing. An entry the account's `.zshenv` puts first therefore survives a login.
+
+A graphical session's programs (a launcher, a bar, a window manager's key bindings) are started from the
+display manager and the service manager, not from a shell, and read none of these files. The service
+manager's own place for the account's environment is `~/.config/environment.d/`. Today it holds nothing
+on any of the four machines, so a program launched from the window manager does not see `PATH` entries
+that a terminal does.
+
+## What the mesh already has for "many modules, one file"
+
+Measured over the catalogue's 69 module definitions:
+
+| mechanism | used by | shape |
+|---|---|---|
+| `contributes` / `receives` | 28 contribute, 15 receive | A consumer contributes **facts** keyed by a requirement. The provider receives all of them as one file in the mesh's own format, and **renders them itself**. "The controller does not know what a reverse proxy is." |
+| `listens` / `filtering` | 40 declare listens, 1 composes | The controller derives the whole firewall rule set from every module's ports and writes it where the holder asks. |
+| `jails` / `jailing` | 3 declare, 1 composes | Each module supplies its jail **in the tool's own format**. The controller assembles them, sorted, into the one file the holder names. |
+| `into: block` on a file | 2 | One module's marked region inside a file something else owns. Text outside the region is kept byte for byte. Placement is at the end, or at the start. |
+
+None of these is a contribution of shell code or of environment today.
@@ -0,0 +1,197 @@
+# 02 — How a module plugs in
+
+Six questions, taken one at a time: the environment, shell code, the operator's own lines, order,
+who renders, and what a contribution is addressed to. Each has the options weighed and a starting
+position. The positions were set with the operator on 2026-10-04 and are what this effort tests, not
+what it has decided.
+
+## 1. The environment: variables and `PATH`
+
+A variable or a `PATH` entry is a fact about the account. It holds whichever shell is the login shell,
+and it is wanted by:
+
+- every shell, interactive or not;
+- the login shell's `execute`;
+- a graphical session's programs.
+
+[01](01-what-the-shell-file-holds-today.md) measures that `.zshrc` reaches only the first kind, and
+only interactively.
+
+| | option | for | against |
+|---|---|---|---|
+| E1 | Each module writes lines into the shell's rc file (today) | nothing new | misses `execute`, scripts and the graphical session; written in one shell's syntax, so a second shell module starts over |
+| E2 | A module contributes environment facts (a variable and its value; a `PATH` entry and its position) **to the login shell**. The holder renders them into its shell's always-read file (`~/.zshenv` for zsh) | reaches every zsh, `execute` included; a contributor names no path and no shell | the graphical session sees none of it; the environment is tied to which module holds the shell; every shell module reimplements the same rendering |
+| E3 | E2, and the service-manager holder (ADR 0177) renders the same facts a second time into `~/.config/environment.d/` | the graphical session sees the same `PATH` as the terminal | one fact set, two owners, two renderings that can disagree; the service manager's module gains a duty unrelated to managing services |
+| E4 | One composed file in `environment.d` syntax, sourced by the shell with export-all | one file, two readers | ties the shell to the service manager's syntax, which is close to POSIX assignments but not equal (its `${VAR:-default}` and quoting rules differ); a value with a space breaks one reader or the other |
+| E5 | Shells take the environment from the service manager's environment generator, which prints the merged `environment.d` | no file of the shell's at all | every shell depends on the service manager and starts a process on every start; the generator's output is unquoted, so a value with a space breaks it |
+| **E6** | **An environment module.** A module of its own (working name `node-env`) holds a mesh seat, `node-environment`, and is the only writer of the account's environment. Every module contributes its variables and `PATH` entries to that seat. The holder writes them in each reader's format: a POSIX file of `export` lines that shells source, and the service manager's `~/.config/environment.d/` | the environment no longer depends on which shell holds `login-shell`; one owner and one rendering per format, both from the same facts; the graphical session included without the service manager's module; a contributor addresses "the environment", never a shell; the `PATH` rules (order, de-duplication) live in one module's code, where a test can hold them | one more module and seat, assigned on every node beside the shell; the `login-shell` protocol gains a duty, to source the environment file, which must be written down and checked |
+
+**Starting position: E6.** It was the operator's proposal on 2026-10-04, and it replaces this
+document's first position (E2, then E3).
+
+- The facts are the contribution. Each format is rendered once, by the one module whose subject is the
+  environment.
+- A shell module's part shrinks to one line in its always-read file: `.zshenv` for zsh, sourcing the
+  environment module's POSIX file. A bash or fish module writes the same line in its own file, and no
+  contributor changes when the login shell does.
+
+Sketched, for a node with zsh, the environment module, and a toolchain:
+
+```
+toolchain ──contributes PATH entry──▶ node-environment ◀──contributes EDITOR, ~/.local/bin── zsh
+                                            │ (held by node-env)
+                         ┌──────────────────┴──────────────────┐
+                         ▼                                     ▼
+              POSIX export file                  ~/.config/environment.d/
+                         ▲                                     ▲
+            sourced from ~/.zshenv               read by the service manager
+            (every zsh, execute too)             (the graphical session)
+```
+
+The shell module still contributes its own environment (`EDITOR`, `XDG_CONFIG_HOME`, `~/.local/bin` on
+`PATH`) as a contributor like any other; it does not write those lines itself. Once issue 168 closes,
+the values a person varies become settings of whichever module contributes them (ADR 0174).
+
+## 2. Shell code: a prompt, plugins, a version manager's loader
+
+This *is* one shell's syntax, and order matters: a prompt's instant-prompt cache must run first, and
+syntax highlighting last.
+
+| | option | for | against |
+|---|---|---|---|
+| S1 | **A contribution of code for one shell** (the shell it is for, the code, a slot), gathered by the controller and placed inside the holder's block in slot order. The same shape as `jails`, which a module supplies in fail2ban's own format and the controller assembles | a contributor names no path; the order is declared and checkable; unassigning the contributor removes its code at the next composition; a node holding fish simply has no zsh code rendered, and the resolver can say so | the controller gains one more gathered field; code for a shell travels in the declaration (in the clear, so no secrets in it, as for any file) |
+| S2 | **A drop-in directory**: each module places its own `~/.zsh/rc.d/NN-name.zsh`, and the shell's block sources the directory | no controller change; each file is its module's own, removed when undeclared | every contributor hard-codes a path inside the shell module's territory, against ADR 0112's spirit; order is a naming convention nothing checks; nothing ties the file to the shell actually being zsh |
+| S3 | Contributions as facts the holder renders (`contributes`/`receives` proper) | one mechanism with question 1 | code is not a fact; the holder would only paste it, which is S1 with an extra file |
+
+**Starting position: S1.** A contribution to the shell carries **only code**, for named shells, each
+piece in a slot. Variables and `PATH` entries never go here; they go to the environment (§1). So a
+module touching both makes two contributions:
+
+- A prompt module contributes zsh code in the first slot, and its own configuration file is its own
+  owned file (ADR 0182).
+- A version manager contributes its directory variable to the environment, and its loader as code
+  for each shell it supports.
+- A toolchain contributes a `PATH` entry to the environment and nothing to the shell.
+
+What has to be settled: what each contribution is *addressed to*. Section 6 covers that.
+
+## 3. The operator's own lines: the "local override"
+
+Assigning the shell module must lose nothing the machine does today. That has two halves.
+
+**What is common is the module's default, not an override.** The startup file is identical on all four
+machines ([01](01-what-the-shell-file-holds-today.md)). A line every machine has is the shell module's
+default, or another module's contribution. It is not a local override that a person would keep in step
+on every machine by hand. Most of today's file therefore moves into the shell module's block and into
+the contributions above. Little of it stays the operator's.
+
+**What is the operator's is everything outside the mesh's block.** The host already works this way:
+
+- the mesh's region is the marked block;
+- text outside it is kept byte for byte, and checked unchanged;
+- the region is given back when the module goes.
+
+| | option | for | against |
+|---|---|---|---|
+| O1 | The mesh's block at the **start** of the file; the operator's lines after it | the operator's lines run last and win, which is what an override means; already supported (`at: start`) | a file the operator later rewrites must keep the markers; the host refuses a broken pair rather than guess |
+| O2 | A named operator region *inside* a file the mesh writes whole (ADR 0174's wording) | the file is entirely the mesh's except one hole | the opposite of what the host implements; a file a person already owns becomes the mesh's |
+| O3 | Only `~/.zshrc.local`, sourced from the block; `~/.zshrc` the mesh's whole | one obvious place | takes over a file the person owns today; ADR 0182 classifies the shell's own file as *written into*, not owned |
+
+**Starting position: O1.** `~/.zshrc.local` keeps working because the operator's own lines source it,
+not because the mesh's block does.
+
+The record this effort becomes corrects ADR 0174's description of the kept region as a **progressive
+insight**: the decision stands (a node varies a module by settings or by the operator's own lines,
+never by an edit), and only its description of which side is marked changes.
+
+**The one-off migration** is a person's act, listed in the module's documentation (ADR 0182):
+
+- remove from today's file every line the block or a contribution now carries;
+- keep the rest below the block.
+
+Until a prompt module and the other contributors exist, the lines they will carry stay among the
+operator's own. Nothing is lost at any step.
+
+## 4. Order
+
+Order matters only for code. The environment is set before any code runs, because zsh reads
+`.zshenv` first. `PATH` entries carry their own position (before or after the system's), which the
+environment module orders, not the shell.
+
+| | option | for | against |
+|---|---|---|---|
+| R1 | Numbers (`10`, `50`, `90`) | familiar | every contributor guesses a number; collisions are silent |
+| R2 | **A few named slots**, `first` / `normal` / `last`, with the module name breaking ties | the prompt says `first` and highlighting says `last` because that is what they mean; the composed result is the same bytes every time | three slots may not be enough |
+
+**Starting position: R2.** Inside the shell module's block, the order is:
+
+1. the line sourcing the environment module's file (in `.zshenv`, so it runs for every zsh; the rest
+   of this list is `.zshrc`);
+2. the `first` slot;
+3. the shell module's own defaults;
+4. the `normal` slot;
+5. the `last` slot.
+
+The operator's lines come after the block, as option O1 says.
+
+## 5. Who renders: the controller or the holder's code
+
+There are two different renderings, and E6 lets them be answered differently.
+
+**The environment** is facts rendered into two fixed formats by the one module whose subject they are.
+
+- The environment module receives the gathered contributions (the `contributes` / `receives` shape:
+  facts in the mesh's own format, rendered by the receiver).
+- Its own code writes the POSIX file and the `environment.d` file whenever what it receives changes.
+  That is ADR 0182's third class, written by the module's own process, owned by the account,
+  atomically.
+- The controller learns no shell and no service manager. The `PATH` rules (prepend or append,
+  de-duplicate, keep the system's entries) are ordinary code with ordinary tests.
+- To settle: what runs that code when the received file changes. The candidates are a host action
+  that restarts on the received file, or a subscription through the runtime (ADR 0198).
+
+**Shell code** is not facts. It is text in the shell's own syntax, assembled in slot order, which is
+what the controller already does for fail2ban jails: sort the pieces and concatenate them into the
+holder's region. The controller assembles; it never interprets the code. This keeps the shell module
+bundle-free for its files, and keeps the composed result visible in the declaration before a machine
+applies it.
+
+## 6. What a contribution is addressed to
+
+Under E6 there are two addressees: the environment and the login shell.
+
+| | option | for | against |
+|---|---|---|---|
+| A1 | **Seats**: environment facts to `node-environment`, shell code to `login-shell`. Each seat's protocol says what its holder does with what is contributed to it | a contributor depends on a role ("the environment", "the login shell"), never on zsh or on one module; works the same for any holder | `login-shell` today is declared by the zsh module itself (ADR 0126). A second shell module may only claim it, never declare it, and the seat exists only while zsh's definition is registered |
+| A2 | Requirements the modules provide (`contributes` keyed by them, as the reverse proxy is) | an existing mechanism | a contributor on a node without the provider fails to resolve, though a toolchain's `PATH` entry with no environment module is merely unwritten |
+
+**Starting position: A1, both seats in the mesh's own seat set** beside the service manager.
+
+- `node-environment` is new, and is the mesh's from the start.
+- `login-shell` moves there from the zsh module's definition. A shell is as universal a role as a
+  service manager, and a protocol that now carries duties (render the shell code contributed to it,
+  source the environment file) should not depend on one module's registration.
+
+Research 023 (a seat's protocol naming what its holder owns) is the general form of this: the
+environment seat would own the two environment files, and the login-shell seat the shell's
+startup-file region. The two efforts should not decide it twice.
+
+## Open questions
+
+- Whether a contribution may be conditional on a capability: the workstation-only environment (a
+  browser, a toolkit theme) is a desktop module's contribution, which arrives only where that module is
+  assigned. Measured, this may need nothing new.
+- What a node without the environment module does with environment contributions: refuse them at
+  resolve, or leave them unwritten and say so. The position here is to say so; a missing `PATH` entry
+  is a visible gap, not a broken machine.
+- Whether the operator's own variables (the script-library paths in [01](01-what-the-shell-file-holds-today.md))
+  are the operator's lines below the shell block, or a kept region of the environment module's file.
+  The first needs nothing new, but reaches only interactive zsh.
+- How the prompt module and a plugin module divide the plugins. Packaging decides it as much as
+  ownership: the plugins come from upstream repositories, not distribution packages, on these machines.
+- Whether the `execute` verb should read the interactive file at all once the environment is in
+  `.zshenv`. The position here is no: a non-interactive login shell plus the environment is what a
+  command needs, and the prompt's code should not run for it.
+- How a contribution reaches a second shell assigned beside the holder, which to-be 38 WP5 names as the
+  first follow-up record. Under A1 a non-holder renders nothing, so the question becomes whether a
+  non-holding shell module may render contributions for interactive use.
@@ -9,6 +9,8 @@ extends: 02-DECISIONS/0011-managed-files-are-generated-never-edited.md

 # 174. A node varies a module through settings and kept regions, never through an edit

+> **The mechanism changed — 2026-10-04, by [ADR 0204](0204-a-module-contributes-shell-code-to-the-login-shell-in-named-slots.md).** Where this record calls a kept region *a marked block in which the operator's own lines are kept*, read the inverse, which is what the host built: the mesh's region is the marked block, and every line outside it is the operator's, kept byte for byte and given back when the module goes. The decision stands: a node varies a module by settings and by the operator's own lines, never by an edit.
+
 ## Context

 [ADR 0011](0011-managed-files-are-generated-never-edited.md) says a managed file is derived and an
@@ -9,6 +9,8 @@ extends: 02-DECISIONS/0132-a-seat-carries-the-tools-its-holder-must-serve.md

 # 176. The login shell is a node seat held by one shell module, and `execute` is its contract

+> **The mechanism changed — 2026-10-04, by [ADR 0204](0204-a-module-contributes-shell-code-to-the-login-shell-in-named-slots.md).** The seat is no longer declared by the shell modules (§1). It is `node-login-shell`, in the mesh's own seat set, which a shell module claims. Its holder also places the shell code other modules contribute, and sources the account's environment ([ADR 0203](0203-the-accounts-environment-is-one-modules-and-every-module-contributes-to-it.md)). What stands: one holder per node, the login shell set by the `user` shape and given back, `execute` as the contract, and any node may call it.
+
 ## Context

 [ADR 0040](0040-what-a-module-is.md) names the shell as its example of a *shared* seat: bash, zsh
@@ -0,0 +1,106 @@
+---
+topic: what runs on it
+status: accepted
+date: 2026-10-04
+deciders: jochen
+reconstructed: false
+extends: 02-DECISIONS/0198-a-modules-long-running-code-is-launched-by-the-node-runtime-and-reaches-the-bus-through-it.md
+---
+
+# 201. A module keeps its current state in key-value buckets it declares, and reaches them through the runtime
+
+## Context
+
+A module's code reaches the bus through the node's runtime: it publishes events, subscribes to them
+and asks tools ([ADR 0198](0198-a-modules-long-running-code-is-launched-by-the-node-runtime-and-reaches-the-bus-through-it.md)).
+Events are kept for a week and replayed to a consumer that was away; requests are kept nowhere. What
+neither gives is **the current value of something**, seen by every machine, including one that joins
+after it was written. The first module to need it — the operator's agent on a machine — registers MCP
+servers for every machine as events, and a machine assigned later never hears of them; and it would
+replay a week of licence rotations where it needs only the binding that holds now. Research
+[024](../01-RESEARCH/024-state-a-module-keeps-on-the-bus/00-overview.md) measured the alternatives and
+the grants against a real server.
+
+[Design 32](../03-DESIGN/01-to-be/32-what-a-module-declares.md) §4 already names *state* as one of the
+mesh's relationships — 1:1, last per subject — and reserves it to the mesh's own declarations.
+[Design 25](../03-DESIGN/01-to-be/25-the-bus-on-nats.md) §1 expects key-value buckets on the bus.
+
+## Considered Options
+
+1. **Key-value buckets a module declares, created by the controller, reached through the runtime.**
+   Chosen.
+2. **State as events on EVENTS, read last-per-subject.** Rejected: retention is per stream and EVENTS
+   keeps seven days, so a value unchanged for a week disappears; a second stream over the same subjects
+   is refused by the server (design 32 §3). And events give no get, list or delete.
+3. **A last-per-subject stream per module, written by hand.** Rejected: it is what a key-value bucket
+   is on the server, without the client's get, list, delete and watch — the mesh writing NATS's
+   key-value layer again.
+4. **State in a module's own files or database, shared by asking a tool.** Rejected for state every
+   machine must see: a machine joining later has to know whom to ask and poll, and an owner that is
+   down answers nothing — the property the bus exists to remove.
+
+## Decision
+
+**1. A module declares its state by name.** `state` names the buckets it owns, by local name; every
+instance of the module may write and read them. `reads` names another module's bucket as
+`<module>.<name>`, read-only. A bucket's options are its owner's: how many past values a key keeps,
+and how long a value lives. A manifest names no bucket, stream or subject (design 32 §1).
+
+**2. One bucket per module per name, mesh-wide.** A key may name a machine by the module's own
+convention; the mesh does not scope buckets per machine.
+
+**3. The controller creates the buckets, from the catalogue, on every raise** — from registration,
+like a seat's stream, so a reader can watch a bucket whose owner is not yet assigned anywhere. A module
+never creates one. The runtime's grant on each bucket is the union of what its carried modules may do:
+an owner's instances write and read, a reader's read.
+
+**4. Each assignment is issued its buckets in its membership** ([ADR 0160](0160-the-mesh-issues-an-assignments-subjects-and-a-runtime-serves-what-it-is-issued.md)),
+by the name the module uses for each and whether it may write. The runtime serves `mesh/state.get`,
+`put`, `delete`, `keys` and `watch` on the bundle's channel from that list, and refuses — with the
+reason — a bucket the module was not issued and a write to one it only reads. A watch delivers the
+current values first, without deletions, then an end-of-current marker, then every change, each as a
+`mesh/state` request the bundle answers.
+
+**5. No secret is stored in a bucket, sealed or not.** A bucket is a stream, and design 32 §10 keeps
+every secret off streams. A value that needs a secret names it; the secret travels on request/reply.
+
+**6. The mesh caps size; a bucket outlives its module.** One value per key and no expiry unless the
+owner says otherwise; at most 256 KiB a value and 64 MiB a bucket. Unassigning a module leaves its
+buckets and what is in them ([ADR 0030](0030-data-outlives-the-mesh-that-declared-it.md)); a bucket
+whose declaration is gone from the catalogue is reported, never removed by the mesh.
+
+## Consequences
+
+- A machine that joins reads the current state at once, and every machine sees a change as it
+  happens, with no consumer created per reader and nothing replayed.
+- The runtime's channel has a sixth verb family, and the SDKs a small state surface over it — a
+  contract, which ADR 0039 admits: it changes when the verbs do, rarely, and every module should be
+  rebuilt when it does.
+- What got harder: the runtime must keep each module to its own buckets, because one principal per
+  machine carries all of them and the server enforces only the union. A write the server refuses
+  surfaces to a client as a timeout, not a refusal, so the runtime's own refusal is what a module sees.
+- The secrets rule is only partly mechanical. Sealed values cannot be recognised; the runtime refuses
+  a value with a field whose name says it is a credential, which catches the ordinary mistake and not a
+  determined one. For the operator's agent this means an MCP server's authorisation header stays out of
+  its bucket.
+- Buckets accumulate as modules come and go; that they are reported rather than removed is the price
+  of not deleting data.
+
+## How it is checked
+
+| Rule | Checked by |
+|---|---|
+| A manifest's state names are local, and a read names a bucket its owner declares | the catalogue's registration check, per manifest; a catalogue test that every `reads` whose owner is present names a bucket that owner declares |
+| Buckets exist for every declared state | the controller's raise asserts them idempotently; its test over a real bus |
+| Owners write, readers only read | the composer's test of the grants, per principal kind; the runtime's refusal test over a real bus |
+| A watch hands current values first, without deletions, then changes | the runtime's test over a real bus |
+| No credential-named field in a value | the runtime's refusal test |
+| Live | one module puts on one machine and another machine's watch sees it; a machine assigned afterwards reads it at start |
+
+## References
+
+- Research [024](../01-RESEARCH/024-state-a-module-keeps-on-the-bus/00-overview.md)
+- [Design 32](../03-DESIGN/01-to-be/32-what-a-module-declares.md) §4 and §10, [design 25](../03-DESIGN/01-to-be/25-the-bus-on-nats.md) §1 and §3
+- [ADR 0030](0030-data-outlives-the-mesh-that-declared-it.md), [ADR 0039](0039-what-the-sdk-holds-and-refuses.md),
+  [ADR 0160](0160-the-mesh-issues-an-assignments-subjects-and-a-runtime-serves-what-it-is-issued.md),
+  [ADR 0198](0198-a-modules-long-running-code-is-launched-by-the-node-runtime-and-reaches-the-bus-through-it.md)
@@ -7,11 +7,14 @@ reconstructed: false
 extends: 02-DECISIONS/0048-a-provider-creates-the-credential-the-mesh-minted.md
 ---

-# 201. A provider declares what it derives for each consumer, and the mesh tells both ends
+# 202. A provider declares what it derives for each consumer, and the mesh tells both ends

-> Written as 0188 on 2026-10-02 and renumbered to 0201 on 2026-10-04: the record of the bundles
-> refactor took 0188 on main while this one waited in a pull request, and the mesh's own code now
-> cites that one. Only the number moved; the decision is the one taken on the 2nd.
+> **Written as 0188 on 2026-10-02, renumbered to 0201, and to 0202 on 2026-10-04.** Twice, for the
+> same reason twice: the bundles refactor took 0188 while this waited in a pull request, and the
+> key-value-buckets record took 0201 while this waited again. Both times the number was free when
+> it was chosen and taken by the time this merged. Only the number moved; the decision is the one
+> taken on the 2nd. The check that refuses two records sharing a number is what caught it, both
+> times — a number is how a record is cited, and three repositories cite this one.

 ## Context

@@ -0,0 +1,131 @@
+---
+topic: what runs on it
+status: accepted
+date: 2026-10-04
+deciders: jochen
+reconstructed: false
+extends: 02-DECISIONS/0177-a-unit-may-be-user-scoped-and-the-service-manager-is-a-node-seat.md
+---
+
+# 203. The account's environment is one module's, and every module contributes to it
+
+## Context
+
+A variable or a `PATH` entry is a fact about the operator's account. A toolchain needs its directory
+on `PATH`, a version manager needs a variable naming its directory, an agent needs a variable that
+turns one of its behaviours off, and the shell sets an editor. Today every one of these is a line of
+one shell's syntax in one hand-written startup file. [Research 025](../01-RESEARCH/025-how-a-module-plugs-into-the-shell/00-overview.md)
+measured on four machines:
+
+- about a quarter of the 65 lines a workstation runs at shell start are environment;
+- written into `.zshrc`, that environment reaches only interactive zsh. It misses the login shell's
+  `execute` verb ([ADR 0176](0176-the-login-shell-is-a-node-seat-and-execute-is-its-contract.md)),
+  every script, and every program a graphical session starts;
+- the service manager's place for the account's environment, `~/.config/environment.d/`, holds
+  nothing on any machine.
+
+The shell module as first written carried some of these lines in its own block and dropped the rest.
+
+## Considered Options
+
+1. **Each module writes its own lines into the shell's startup file.** Rejected: one shell's syntax,
+   read by one kind of start, and the same lines rewritten by every shell module.
+2. **Contribute the facts to the login shell, whose holder renders them.** Rejected: the environment
+   then depends on which module holds the shell, every shell module renders the same facts again, and
+   the graphical session sees nothing.
+3. **Option 2, and the service manager's holder renders the same facts a second time** into
+   `environment.d`. Rejected: one fact set with two owners, whose renderings can disagree, and a
+   duty for the service manager unrelated to managing services.
+4. **One file in `environment.d` syntax, sourced by shells.** Rejected: that syntax is close to
+   POSIX assignment but not equal, and a value one reader accepts breaks the other.
+5. **Shells read the service manager's environment generator.** Rejected: every shell start then
+   runs a process and depends on the service manager, and the output is unquoted.
+6. **A module of its own holds the environment.** One mesh seat, held by one module per node,
+   whose files are the account's environment. Every module contributes facts to it, and those facts
+   are written in each reader's format. Chosen. It was the operator's proposal.
+
+Within option 6, two ways to write the files:
+
+- **a. The holder's own code renders what it receives.** This was research 025's starting position.
+  Rejected: the code needs something to run it whenever a contribution changes, and the result exists
+  only after a machine has applied and run it.
+- **b. The controller renders the facts into the holder's files,** in two named formats, at
+  composition. Chosen. The result is in the declaration before any machine applies it, nothing has to
+  trigger anything, and the two formats are standards: POSIX shell assignment and the service
+  manager's `environment.d`. The controller learns no shell. It writes an assignment in a standard
+  syntax, as it already writes a fail2ban stanza a module supplied.
+
+## Decision
+
+**1. The environment is a node seat, `node-environment`, in the mesh's own set.** One module per node
+holds it, and it is the only writer of the account's environment. The first holder is a module of its
+own (working name `node-env`), with no package and no process.
+
+**2. Any module contributes to it with `environment`:**
+
+- **`variables`:** names and values. A name is a POSIX variable name and never `PATH`. A value is
+  literal; it may use `${machine:…}`, resolved first, and may not contain `$`, a quote, a backslash or
+  a line break. The only expansion is the mesh's own, so the two formats cannot read one value
+  differently.
+- **`path`:** entries, each placed at the `start` or the `end` of the account's `PATH`.
+
+**3. The holder places the rendered environment with two placeholders** in its own files:
+
+- **`${environment:posix}`** renders lines a POSIX shell sources:
+  - every variable exported;
+  - every `PATH` entry added only if missing, so sourcing twice changes nothing.
+- **`${environment:systemd}`** renders the same facts as the service manager's user environment, with
+  the account's existing `PATH` kept between the start and the end entries.
+
+Each rendered line names the module that contributed it, so the file answers *where did this come
+from*. Contributions are ordered by module name, and then in the order a module declared them.
+
+**4. The seat's protocol fixes where the POSIX file is:** `~/.config/mesh/environment.sh` under the
+account's home. A shell sources that path without knowing which module wrote it. The service
+manager's file is `~/.config/environment.d/50-mesh.conf`.
+
+**5. Refused at composition:**
+
+- two modules on one node setting the same variable, both named;
+- an environment placeholder in a module that does not claim `node-environment`.
+
+A node with contributions and no holder writes them nowhere. The holder's absence is visible in the
+node's assignments, and no contributor is refused for it, because a missing `PATH` entry is a gap, not
+a broken machine.
+
+## Consequences
+
+- A shell's part in the environment is one line in its always-read startup file, sourcing the
+  POSIX file. A second shell module writes the same line in its own syntax, and no contributor
+  changes when the login shell does.
+- The graphical session sees the same `PATH` as the terminal, from the same facts.
+- The controller gains one gathered field and two renderers. Both are tested byte for byte, like
+  the jails a node composes ([to-be 31](../03-DESIGN/01-to-be/31-a-module-declares-its-fail2ban-jail.md)).
+- What a person sets for themselves stays theirs: variables of their own sit in their own lines of
+  their shell's file, read after the mesh's.
+- **What got harder:** a value that needs another variable expanded (`$HOME`, `$XDG_CONFIG_HOME`)
+  must be written with the mesh's own `${machine:…}` facts, or it is refused. Expansion at shell start
+  is exactly what made one value mean two things in two readers.
+- Once [issue 168](../04-ISSUES/168-a-setting-reaches-every-file-and-contribution/00-report.md)
+  closes, a value a person varies becomes a setting of the module that contributes it
+  ([ADR 0174](0174-a-node-varies-a-module-through-settings-and-kept-regions-never-an-edit.md)).
+
+## How it is checked
+
+| Rule | Checked by |
+|---|---|
+| Both renderings, byte for byte, from a fixed set of contributions | the controller's environment tests |
+| Sourcing the POSIX rendering twice leaves `PATH` unchanged | the same tests, running `sh` over the rendering |
+| A variable set by two modules is refused, naming both | the controller's resolve test |
+| An environment placeholder outside the holder is refused | the catalogue check, which registration runs |
+| A value with `$`, a quote, a backslash or a line break is refused | the manifest's parse test |
+| The zsh holder sources the path the seat fixes | the catalogue's zsh test |
+
+## References
+
+- [Research 025](../01-RESEARCH/025-how-a-module-plugs-into-the-shell/00-overview.md)
+- [ADR 0174](0174-a-node-varies-a-module-through-settings-and-kept-regions-never-an-edit.md),
+  [ADR 0176](0176-the-login-shell-is-a-node-seat-and-execute-is-its-contract.md),
+  [ADR 0177](0177-a-unit-may-be-user-scoped-and-the-service-manager-is-a-node-seat.md),
+  [ADR 0182](0182-inside-a-home-the-mesh-owns-what-it-places-and-holds-the-rest-as-found.md)
+- [To-be 41](../03-DESIGN/01-to-be/41-the-shell-and-the-accounts-environment.md)
@@ -0,0 +1,131 @@
+---
+topic: what runs on it
+status: accepted
+date: 2026-10-04
+deciders: jochen
+reconstructed: false
+extends: 02-DECISIONS/0176-the-login-shell-is-a-node-seat-and-execute-is-its-contract.md
+---
+
+# 204. A module contributes shell code to the login shell in named slots, and the login shell is the mesh's seat
+
+## Context
+
+Some of what a shell runs at start is code in that shell's own syntax, and it belongs to other
+modules:
+
+- a prompt theme loads itself and its configuration;
+- plugins load themselves;
+- a version manager sources its loader.
+
+Order matters: a prompt's instant-prompt cache must run first, and syntax highlighting last. The
+predecessor kept all of this in one file per machine, and installed the theme and plugins by cloning
+them in a hook.
+[Research 025](../01-RESEARCH/025-how-a-module-plugs-into-the-shell/00-overview.md) measured that file
+as byte-identical on four machines. It carries:
+
+- the shell's defaults;
+- code belonging to four other pieces of software;
+- a handful of the operator's own lines.
+
+Nothing gave the other pieces a way in.
+
+Two further facts bear on the seat itself:
+
+- **The seat is declared by the zsh module** ([ADR 0176](0176-the-login-shell-is-a-node-seat-and-execute-is-its-contract.md)
+  §1, under [ADR 0126](0126-a-module-declares-its-own-seats.md)). The controller refuses a second
+  module declaring a seat name, so fish or bash could only ever claim it, and the seat exists only
+  while zsh's definition is registered.
+- **The kept region is the other way round.** [ADR 0174](0174-a-node-varies-a-module-through-settings-and-kept-regions-never-an-edit.md)
+  describes a kept region as a marked block holding the operator's lines. The host built the inverse:
+  the mesh's region is the marked block, and every byte outside it is kept, verified unchanged, and
+  given back when the module goes.
+
+## Considered Options
+
+1. **A drop-in directory** that each module places a file in, and the shell sources. Rejected: every
+   contributor names a path inside the shell module's territory
+   ([ADR 0112](0112-a-module-definition-names-no-node-mesh-or-path.md)); order becomes a naming
+   convention nothing checks; and nothing ties the file to the shell actually being the one it is
+   written for.
+2. **Facts the holder renders**, through `contributes` / `receives`. Rejected: code is not a fact,
+   and the holder would only paste it.
+3. **Code contributed for a named shell in a named slot, assembled by the controller into the
+   holder's file.** This is what the controller already does for fail2ban jails: each module supplies
+   text in the tool's own format, and the controller sorts and concatenates it into the holder's file
+   without interpreting it. Chosen.
+
+For order, numbers (`10`, `50`, `90`) were rejected: every contributor guesses one, and collisions are
+silent. **Three named slots** were chosen: `first`, `normal`, `last`.
+
+## Decision
+
+**1. `node-login-shell` is a node seat in the mesh's own set,** with the verb `execute`. It replaces
+the module-declared `login-shell`. Everything else ADR 0176 decided stands: the holder sets the
+account's login shell through the `user` shape, `execute` is the contract, and any node may call it.
+A shell module claims the seat; none declares it.
+
+**2. Any module contributes shell code with `shell`:** entries naming the shell they are for (`zsh`,
+`bash`, `fish`), the slot, and the code. The controller does not read the code.
+
+**3. The holder places the code with placeholders** in its own files: `${shell:<shell>:<slot>}`. Each
+is filled with that shell's code for that slot, from every module on the node:
+
+- ordered by module name;
+- each piece preceded by a line naming its module;
+- empty when nothing is contributed.
+
+A shell-code placeholder in a module that does not claim `node-login-shell` is refused.
+
+**4. The holder's duties, which are the seat's protocol:**
+
+- Source the account's environment ([ADR 0203](0203-the-accounts-environment-is-one-modules-and-every-module-contributes-to-it.md))
+  from the startup file every start of that shell reads. For zsh that is `.zshenv`, which a script, a
+  login and `execute` all read.
+- Write its interactive block at the **start** of the interactive startup file, so the operator's own
+  lines run after the mesh's and win.
+- Run `execute` as a non-interactive login shell in the account's home:
+  - bounded below the runtime's call limit;
+  - its output bounded;
+  - its whole process group ended on timeout.
+
+**5. The marked block is the mesh's; everything outside it is the operator's.** This is how ADR 0174's
+"kept region" is built. That record keeps its decision and gains a note saying where the mechanism
+lives.
+
+## Consequences
+
+- A prompt, a plugin and a version manager are each a module with its own package or archive, its own
+  configuration file, and a contribution. Assigning one adds its line to the shell, and unassigning it
+  takes the line away at the next composition.
+- Assigning the shell module loses nothing the machine does today:
+  - what is common to every machine becomes the shell module's default or another module's
+    contribution;
+  - what is the operator's stays below the block.
+- **The one-off migration is a person's act**, listed in the shell module's documentation
+  ([ADR 0182](0182-inside-a-home-the-mesh-owns-what-it-places-and-holds-the-rest-as-found.md)):
+  delete the lines the block now carries from the found file.
+- `login-shell.execute` becomes `node-login-shell.execute`. Nothing has called it yet; the shell
+  module was never assigned.
+- **What got harder:** a module wanting a line in the shell must say which shell and which slot, and a
+  module supporting three shells writes its code three times. That is the honest cost of code in
+  three syntaxes.
+
+## How it is checked
+
+| Rule | Checked by |
+|---|---|
+| Code lands in its slot, in module order, only for its shell | the controller's shell-contribution tests |
+| A shell-code placeholder outside the holder is refused | the catalogue check |
+| `node-login-shell` is the mesh's, and no module may declare it | the seat table's tests |
+| The zsh block sits at the start, sources the environment from `.zshenv`, and holds the three slots | the catalogue's zsh test |
+| `execute` is bounded in time and output and kills its process group | the zsh module's tool tests over real child processes |
+
+## References
+
+- [Research 025](../01-RESEARCH/025-how-a-module-plugs-into-the-shell/00-overview.md)
+- [ADR 0174](0174-a-node-varies-a-module-through-settings-and-kept-regions-never-an-edit.md),
+  [ADR 0176](0176-the-login-shell-is-a-node-seat-and-execute-is-its-contract.md),
+  [ADR 0203](0203-the-accounts-environment-is-one-modules-and-every-module-contributes-to-it.md),
+  [to-be 31](../03-DESIGN/01-to-be/31-a-module-declares-its-fail2ban-jail.md)
+- [To-be 41](../03-DESIGN/01-to-be/41-the-shell-and-the-accounts-environment.md)
@@ -0,0 +1,69 @@
+---
+topic: what runs on it
+status: accepted
+date: 2026-10-04
+deciders: jochen
+reconstructed: false
+---
+
+# 205. Software the distribution does not package ships as a pinned archive of the module's own
+
+## Context
+
+The prompt theme the operator uses is not in the distribution's repositories. Its two plugins and an
+autocomplete plugin are. The predecessor installed all four by running `git clone` against their
+upstream repositories from an install hook. That way:
+
+- the version on a machine was whatever upstream's default branch held the day the hook ran;
+- two machines set up a week apart could differ;
+- a machine with no route to upstream failed its install.
+
+The mesh already has a pinned, delivered form for a module's own files: an **archive artifact** built
+from a directory of the module's source, delivered by the artifact store, unpacked by the host's
+`archive` resource, and pinned by digest. One showcase module uses it.
+
+## Considered Options
+
+1. **Clone from upstream on the machine,** as the predecessor did. Rejected: unpinned, unreproducible,
+   and it needs upstream reachable from every machine.
+2. **Build from the distribution's user repository.** Rejected: the host installs packages from the
+   distribution's own repositories. A user-repository build is a toolchain on every machine for one
+   theme.
+3. **Vendor a pinned upstream release into the module's directory and ship it as the module's archive
+   artifact.** Chosen. The release and its version are named in the module, its licence travels with
+   it, and every machine gets the same bytes from the mesh's own store.
+
+## Decision
+
+**A module whose software the distribution does not package carries a pinned upstream release in its
+own source directory and ships it as an archive artifact.**
+
+- The module's documentation names the upstream, the version and the licence.
+- The host unpacks it with the `archive` resource into a directory the module owns.
+- An upgrade is a change to the module, reviewed like any other.
+
+Software the distribution *does* package is installed as a package; a vendored copy of it is
+refused in review.
+
+## Consequences
+
+- The catalogue grows by the size of what it vendors: 1.4 MB for the prompt theme at the pinned
+  release.
+- Upstream's security fixes reach a machine only when somebody updates the module. That is the same
+  trade every pinned dependency makes, and it is visible: the version is in the module.
+- **What got harder:** a vendored program that downloads more at run time, as the prompt theme does
+  for its git status helper, still fetches that part from upstream on first use. This record pins
+  what the mesh ships, not what the software fetches for itself. The module's documentation says so.
+
+## How it is checked
+
+| Rule | Checked by |
+|---|---|
+| The archive is pinned by digest | the host's declaration validation, which refuses an archive without one |
+| The upstream, version and licence are named | review of the module's documentation; the module's test asserts the licence file is in the archive |
+| Packaged software is not vendored | review |
+
+## References
+
+- [ADR 0204](0204-a-module-contributes-shell-code-to-the-login-shell-in-named-slots.md)
+- [To-be 41](../03-DESIGN/01-to-be/41-the-shell-and-the-accounts-environment.md)
@@ -190,7 +190,7 @@ python3 00-META/checks/index.py            fail if stale
 - **0187** — [A dead tracker is not the machine's failure](0187-a-dead-tracker-is-not-the-machines-failure.md)
 - **0189** — [The store keeps what the records name, and a maintenance step holds its writers still](0189-the-store-keeps-what-the-records-name.md)
 - **0190** — [A seat's work is shared by its holders, and building is the first such role](0190-a-seats-work-is-shared-by-its-holders-and-building-is-the-first-such-role.md)
- **0201** — [A provider declares what it derives for each consumer, and the mesh tells both ends](0201-a-provider-declares-what-it-derives-for-each-consumer.md)
+- **0202** — [A provider declares what it derives for each consumer, and the mesh tells both ends](0202-a-provider-declares-what-it-derives-for-each-consumer.md)

 ### Its tiers, from the bottom up

@@ -300,6 +300,10 @@ python3 00-META/checks/index.py            fail if stale
 - **0195** — [The mesh's tools are found by address, not announced whole](0195-the-meshs-tools-are-found-by-address-not-announced-whole.md)
 - **0197** — [Every tool announces itself on the bus, in the NATS services protocol](0197-every-tool-announces-itself-on-the-bus-in-the-nats-services-protocol.md)
 - **0198** — [A module's long-running code is launched by the node's runtime, and reaches the bus through it](0198-a-modules-long-running-code-is-launched-by-the-node-runtime-and-reaches-the-bus-through-it.md)
+- **0201** — [A module keeps its current state in key-value buckets it declares, and reaches them through the runtime](0201-a-module-keeps-its-current-state-in-key-value-buckets-it-declares-and-reaches-through-the-runtime.md)
+- **0203** — [The account's environment is one module's, and every module contributes to it](0203-the-accounts-environment-is-one-modules-and-every-module-contributes-to-it.md)
+- **0204** — [A module contributes shell code to the login shell in named slots, and the login shell is the mesh's seat](0204-a-module-contributes-shell-code-to-the-login-shell-in-named-slots.md)
+- **0205** — [Software the distribution does not package ships as a pinned archive of the module's own](0205-software-the-distribution-does-not-package-ships-as-a-pinned-archive-of-the-module.md)

 ### How it is built

@@ -7,8 +7,10 @@ code:
  - mesh-tools src/broker-amqp.ts (to be replaced)
  - mesh-catalog modules/nats (to be written)
  - mesh-sdk src (the protocol's NATS binding, step 3)
-updated: 2026-10-02
+  - mesh-tools node-tools/internal/bus (a module's state, ADR 0201)
+updated: 2026-10-04
 decisions:
+  - 02-DECISIONS/0201-a-module-keeps-its-current-state-in-key-value-buckets-it-declares-and-reaches-through-the-runtime.md
  - 02-DECISIONS/0167-a-membership-carries-what-its-module-receives-and-who-the-mesh-is.md
  - 02-DECISIONS/0160-the-mesh-issues-an-assignments-subjects-and-a-runtime-serves-what-it-is-issued.md
  - 02-DECISIONS/0157-a-build-says-what-it-does-on-the-bus-as-it-happens.md
@@ -48,6 +50,7 @@ mesh's own state lives, and where what a module may say is decided by what it de
 | **events** — a module says something happened | 1:many | delivered to every consumer that declared it; dead-lettered when it cannot be |
 | **tools** — a module or a person asks another's tool | request/reply | one answer, from one server, or a timeout |
 | **work to a role** — a module submits to a capability without knowing who provides it | job | exactly one holder does it; it queues while nobody does |
+| **state** — a module's current value of something, every machine reading it | key-value | the newest per key, kept until replaced or deleted; read whole by a machine that joins later |

 The last two rows are the ones worth dwelling on, because they are not messaging in the sense of
 carrying bytes from A to B. **A role is addressable**, so a caller names the capability and never
@@ -56,7 +59,8 @@ changing ([ADR 0126](../../02-DECISIONS/0126-a-module-declares-its-own-seats.md)
 property of the mesh's architecture that happens to be expressed in subjects.

 And more of the mesh lands here as it is built: conditions and observed state in key-value
-buckets that anything may watch, the server's own advisories becoming observations like any other
+buckets that anything may watch — the first of them a module's own declared state, *2026-10-04*
+([ADR 0201](../../02-DECISIONS/0201-a-module-keeps-its-current-state-in-key-value-buckets-it-declares-and-reaches-through-the-runtime.md)) — the server's own advisories becoming observations like any other
 ([research 017](../../01-RESEARCH/017-a-mesh-that-heals-itself/00-overview.md)), and a person's
 client speaking the bus directly rather than through a surface built over it (§7). None of that
 is a message being moved; all of it is the bus being the mesh's centre.
@@ -84,8 +88,16 @@ mesh.seat.<seat>.event.<verb>     a role's own event           (JetStream: EVENT
 mesh.seat.<seat>.tool.<verb>      a role's tool                (core request/reply)
 mesh.ask.<node>.<command>         the controller's command api (core request/reply)
 mesh.assignment.<node>.<module>   an assignment's membership   (JetStream: ASSIGNMENTS, last-per-subject)
+$KV.<module>_<name>.<key>          a module's state             (JetStream: a key-value bucket per declared name)
 ```

+**Added 2026-10-04** ([ADR 0201](../../02-DECISIONS/0201-a-module-keeps-its-current-state-in-key-value-buckets-it-declares-and-reaches-through-the-runtime.md)):
+the last row is outside `mesh.` on purpose. A key-value bucket is NATS's own construct and lives
+under NATS's own prefix, which is what lets the server's key-value layer — direct reads, rollups,
+delete markers, watches — do the work instead of the mesh writing it again. The bucket is named for
+the module and the local name joined by an underscore, which neither may contain, so two modules can
+never derive one bucket.
+
 **Revised 2026-10-01** ([ADR 0160](../../02-DECISIONS/0160-the-mesh-issues-an-assignments-subjects-and-a-runtime-serves-what-it-is-issued.md)): the rows above
 for a module's and a seat's tools are the shapes the controller *issues*, not rules a runtime carries.
 Every assignment is published a membership — what it serves and where, in which queue, its seat verbs,
@@ -155,6 +167,7 @@ Core NATS is at-most-once. Everything the mesh must not lose lives in a JetStrea
 | CONTROL | `mesh.control.>` except `alive` (a build's outcome moved to its seat, ADR 0121) | work queue, one consumer (the controller), explicit ack | the store-window guarantee ([ADR 0083](../../02-DECISIONS/0083-one-push-leaves-the-mesh-consistent.md)): the controller `nak`s with a delay while its store is away and the message is redelivered; nothing is dropped |
 | NODES | `mesh.node.>` | last per subject | one declaration per node, always the newest |
 | EVENTS | `mesh.mod.*.event.>` and `mesh.seat.*.event.>` | limits (age, size), durable consumer per subscribing module | a subscriber that was down catches up; after `max-deliver` attempts the advisory feeds `mesh.events.dead` (its own small stream). *2026-10-01:* a build's whole log is here too, as the build-machine seat's `log.<build id>` events ([ADR 0157](../../02-DECISIONS/0157-a-build-says-what-it-does-on-the-bus-as-it-happens.md)) — one subject per build, a week of retention, read back by `builds --log <id>` with a consumer that is gone when the reading is done |
+| `KV_<module>_<name>` | `$KV.<module>_<name>.>` | the newest value per key — as many past values as the owner declared — no age unless the owner declared one; a value at most 256 KiB, a bucket at most 64 MiB | a module's state (ADR 0201): one per name in a manifest's `state`, created from the catalogue on every raise, so it exists before its owner runs anywhere; kept when the module is unassigned, because what it holds is data |

 Tool calls and heartbeats stay on core NATS: a lost heartbeat is the next heartbeat; a lost tool
 call is a timeout the caller already handles.
@@ -234,6 +247,14 @@ expresses this exactly, per subject, and better than a vhost could:
  permissions for each consumed event's subject, its tool subjects, and that same inbox prefix.
  Nothing else. A module that tries to publish outside its emits is refused by the server, not by
  convention.
+- **A module's state** (ADR 0201), for whichever principal carries the module — today the machine's
+  runtime, whose grant is the union of its modules': binding to the bucket, reading a key directly,
+  and an ordered consumer for listing and watching, created and deleted on the bucket's own stream
+  and nothing else's; and, for the owner's instances only, publishing under the bucket's own
+  `$KV.<bucket>.>`. *Measured 2026-10-04 against a running server:* without the consumer-delete
+  grant a watch cannot be stopped cleanly, and a write the server refuses reaches the writer as a
+  timeout rather than a refusal — so the runtime refuses first, from the membership, and the grant
+  is the second line.
 - **The controller's user** owns `mesh.control.>`, `mesh.node.>` and the streams, and may submit work
  to the seats the mesh's own flows use — a build, for one (ADR 0121).
  **A host's user** may publish its own `mesh.control.<node>.>` and subscribe its own
@@ -14,7 +14,7 @@ decisions:
  - 02-DECISIONS/0084-which-provider-serves-a-consumer.md
  - 02-DECISIONS/0046-a-module-configuration-is-its-assignments-not-its-manifest.md
  - 02-DECISIONS/0038-the-mesh-assigns-the-port.md
-  - 02-DECISIONS/0201-a-provider-declares-what-it-derives-for-each-consumer.md
+  - 02-DECISIONS/0202-a-provider-declares-what-it-derives-for-each-consumer.md
 ---

 # 27 — A module requires, the mesh resolves
@@ -208,7 +208,7 @@ the placeholder allows: the definition says which values reach which requirement
 does. *How it is checked:* the unit tests named in issue 173, and the plan comparison that closed it.

 *A provider says once what it derives for each consumer (2026-10-02,
-[ADR 0201](../../02-DECISIONS/0201-a-provider-declares-what-it-derives-for-each-consumer.md),
+[ADR 0202](../../02-DECISIONS/0202-a-provider-declares-what-it-derives-for-each-consumer.md),
 [issue 124](../../04-ISSUES/124-a-consumer-cannot-be-told-what-its-provider-derived/00-report.md)):*
 where a provider **names the resource** it gives each consumer — a bucket, a database, a vhost — the
 name is derived per consumer, and a literal `serves` block could not carry it. A served value may
@@ -221,7 +221,7 @@ its binding's served facts and as `${bound:<provision>:<key>}` in any file it wr
 as `derived` on that consumer's entry in its contributions file, so its provisioner is told the name
 rather than recomputing it. A consumer that writes the derived value into its own definition instead
 of asking for it is refused, naming the placeholder to use. *How it is checked:* the unit tests in
-ADR 0201's "how this is checked", each run against the unchanged controller first.
+ADR 0202's "how this is checked", each run against the unchanged controller first.

 ## How a definition reads what was resolved

@@ -11,8 +11,10 @@ code:
  - mesh-host internal/apply/apply.go
  - mesh-tools src/main.ts
  - mesh-catalog modules/mesh-catalog
-updated: 2026-10-02
+  - mesh-tools node-tools/internal/runtime (a module's state, ADR 0201)
+updated: 2026-10-04
 decisions:
+  - 02-DECISIONS/0201-a-module-keeps-its-current-state-in-key-value-buckets-it-declares-and-reaches-through-the-runtime.md
  - 02-DECISIONS/0160-the-mesh-issues-an-assignments-subjects-and-a-runtime-serves-what-it-is-issued.md
  - 02-DECISIONS/0126-a-module-declares-its-own-seats.md
  - 02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md
@@ -67,6 +69,8 @@ the catalogue, and the mesh would have hundreds of copies of a decision it made
 | `tools: status` | queue-group subscription on `mesh.mod.<module>.tool.status` |
 | seat `telegram-sender`, `accepts: send` | work-queue consumer on `mesh.seat.telegram-sender.accept.send` |
 | `uses: telegram-sender` | publish on that seat's `accept` subjects, and nothing else |
+| `state: servers` | a key-value bucket for the module, created by the controller; its instances write and read it |
+| `reads: billing.orders` | read and watch billing's `orders` bucket, and nothing else of it |

 **Wildcards, and they are the mesh's rather than a bus's.** *Added 2026-09-27, from
 [issue 127](../../04-ISSUES/127-a-module-event-derives-a-subject-nothing-publishes/00-report.md).* A
@@ -221,7 +225,7 @@ service" versus "one worker per machine".
 | credential | sealed, per consumer | none | none | none | none |
 | reply | — | none | none, or an event later | a report | awaited |
 | retention | — | age and size | work queue, explicit ack | **last per subject** | none |
-| declared | `provides`/`requires` | `emits`/`consumes` | seat `accepts` / `uses` | the mesh's own | `serves` |
+| declared | `provides`/`requires` | `emits`/`consumes` | seat `accepts` / `uses` | the mesh's own; a module's `state` / `reads` | `serves` |

 **Job** is the one [ADR 0041](../../02-DECISIONS/0041-events-are-a-relationship.md) had no room
 for. Its table has events at 1:many and provisions at 1:1; a module submitting work to a service
@@ -236,6 +240,31 @@ last-per-subject retention, and a node that has seen sequence *n* refuses *n−1
 That is the wire-level answer to
 [issue 107](../../04-ISSUES/107-a-declaration-carries-no-order/00-report.md).

+**A module declares state too.** *Added 2026-10-04,
+[ADR 0201](../../02-DECISIONS/0201-a-module-keeps-its-current-state-in-key-value-buckets-it-declares-and-reaches-through-the-runtime.md).*
+State was the mesh's alone, and modules had the same need with nowhere to put it: an MCP server
+registered for every machine, sent as an event, never reached a machine assigned afterwards — its
+consumer did not exist yet when the event passed — and a licence binding sent as events replays a
+week of rotations where only the latest matters. So a module names the state it **owns** with
+`state`, and another module's it **reads** with `reads: <module>.<name>`. Each is a key-value bucket
+the controller creates from the catalogue, mesh-wide, existing from registration so a reader can
+watch before the owner runs anywhere ([design 25](25-the-bus-on-nats.md) §3). Every instance of the
+owner writes; a reader reads and watches. A key may name a machine by the module's own convention;
+the mesh keeps one bucket per name, not one per machine, because "every server, for every machine"
+is then one list rather than a walk.
+
+What a module sees is what it named. Its assignment's membership lists its buckets by those names,
+with whether it may write, and the runtime answers `get`, `put`, `delete`, `keys` and `watch` for
+them on the bundle's channel — refusing, with the reason, a name it was not issued or a write to a
+bucket it only reads. A watch hands the current values first, then every change: a bundle that starts
+late, or starts again, has the whole of the state before it has any of the news.
+
+The owner says how many past values a key keeps and how long a value lives, as a seat says how long
+its backlog survives (§3); the mesh caps a value's size and a bucket's. **A bucket outlives its
+module's assignment** — what a module stored is data
+([ADR 0030](../../02-DECISIONS/0030-data-outlives-the-mesh-that-declared-it.md)) — and one whose
+declaration is gone is reported, never removed by the mesh.
+
 ## 5. Seats

 A module declares a seat with its protocol, and the mesh enforces one holder at its scope
@@ -454,6 +483,14 @@ sealing key leaks, that stream is an archive rather than a moment. So:
  existing discipline — *fetched from it, not carried* — applied to the one payload where carrying
  it is worst.

+**A key-value bucket is a stream, so the same holds for it.** *Added 2026-10-04,
+[ADR 0201](../../02-DECISIONS/0201-a-module-keeps-its-current-state-in-key-value-buckets-it-declares-and-reaches-through-the-runtime.md).*
+No secret is put in a module's state, sealed or not: state is exactly what a machine joining a year
+later reads in full. A value that needs a secret names it, and the secret travels on request/reply.
+Sealed values are plain text to anything inspecting them, so this is checked only partly — the
+runtime refuses a value carrying a field whose name says it is a credential, which catches the
+ordinary mistake and not a determined one.
+
 **The bootstrap, which is circular and has a precedent.** The vault makes every secret
 ([ADR 0113](../../02-DECISIONS/0113-the-vault-makes-every-secret.md)), including the bus's own
 passwords. The vault is a module, and a module needs a bus account, whose password the vault
@@ -523,3 +560,9 @@ billing existing under that name.
  on, and exactly those two are rebuilt.
 - **A stale declaration is refused.** A bed: replay sequence *n−1* after *n*, and the node refuses
  it rather than applying it.
+- **A module reaches only the state it declared.** The composer's test: an owner's runtime may write
+  its buckets, a reader's may only read, and nothing else is granted; the runtime's test over a real
+  bus: a name not issued and a reader's write are refused with the reason.
+- **State is current at once.** The runtime's test over a real bus: a watch hands the current values
+  without deletions, then an end-of-current marker, then changes. Live: a machine assigned after a put
+  reads it at start.
@@ -2,7 +2,7 @@
 layer: to-be
 status: in-progress
 code: [mesh-host, mesh-controller, mesh-tools, mesh-catalog]
-updated: 2026-10-02
+updated: 2026-10-04
 decisions:
  - 02-DECISIONS/0173-the-operators-machine-is-the-meshs-and-a-module-is-what-it-declares.md
  - 02-DECISIONS/0174-a-node-varies-a-module-through-settings-and-kept-regions-never-an-edit.md
@@ -33,12 +33,16 @@ This is the design [to-be 29](29-a-node-has-operator-accounts.md) §2 called *a
 Worked on the first one, a shell. The `zsh` module declares:

 - a **package**, `zsh`;
- **files under the home**, owned by the account: the shell's rc file with the module's default
-  configuration, carrying a kept region for the operator's own lines, and `${setting:…}`
-  placeholders for the few values a node varies; the account and its home are machine facts the
-  controller resolves ([ADR 0112](../../02-DECISIONS/0112-a-module-definition-names-no-node-mesh-or-path.md),
-  to-be 29 §2);
- a **seat declaration**, `login-shell`, node-scoped, with its one verb; and a **claim** on it;
+- **files under the home**, owned by the account: the mesh's block at the start of the shell's rc
+  file with the module's default configuration and the slots other modules' code lands in, the
+  operator's own lines kept after it, and `${setting:…}` placeholders for the few values a node
+  varies; the account and its home are machine facts the controller resolves
+  ([ADR 0112](../../02-DECISIONS/0112-a-module-definition-names-no-node-mesh-or-path.md),
+  to-be 29 §2). Its environment is a contribution to the environment module, not lines of its own
+  ([ADR 0203](../../02-DECISIONS/0203-the-accounts-environment-is-one-modules-and-every-module-contributes-to-it.md),
+  [ADR 0204](../../02-DECISIONS/0204-a-module-contributes-shell-code-to-the-login-shell-in-named-slots.md),
+  [to-be 41](41-the-shell-and-the-accounts-environment.md));
+- a **claim** on the mesh's node-scoped seat `node-login-shell`, with its one verb;
 - a **`user` shape** naming the shell, applied only where the module holds the seat;
 - a **tools bundle**, the artifact kind for interpreted code, with `execute` and the module's own
  `show-config`.
@@ -80,7 +84,8 @@ root escalates itself.

 ## 4. The seats of the environment

-Decided now: **`login-shell`** (module-declared; zsh, fish, bash; verb `execute`) and
+Decided now: **`node-login-shell`** (the mesh's own, ADR 0204; zsh, fish, bash; verb `execute`),
+**`node-environment`** (the mesh's own, ADR 0203; the environment module; no verbs) and
 **`node-service-manager`** (the mesh's own; systemd; verbs over units in both scopes). The rest
 are candidates from [research 018](../../01-RESEARCH/018-the-operators-machine-as-modules/04-the-seats-of-the-environment.md),
 one record each when its first holder is written: display server, display session, terminal
@@ -15,6 +15,7 @@ decisions:
  - 02-DECISIONS/0192-a-tools-bundle-declares-what-it-is-given-and-the-runtime-hands-it-to-that-bundle-alone.md
  - 02-DECISIONS/0193-every-bundle-the-runtime-serves-is-launched-and-the-runtime-knows-no-language.md
  - 02-DECISIONS/0198-a-modules-long-running-code-is-launched-by-the-node-runtime-and-reaches-the-bus-through-it.md
+  - 02-DECISIONS/0204-a-module-contributes-shell-code-to-the-login-shell-in-named-slots.md
 ---

 # 38. Building the operator's machine
@@ -330,6 +331,13 @@ tool of each.

 ## WP5 — The shell, on a server first

+*Replaced on 2026-10-04 by [to-be 41](41-the-shell-and-the-accounts-environment.md).* A review before
+assigning found that the shell module would duplicate every machine's existing startup file, drop
+lines from it, leave the prompt uninstalled, and could not be unassigned
+([issue 228](../../04-ISSUES/228-a-login-the-mesh-set-is-never-given-back/00-report.md)). The shell,
+its environment, the modules that plug into it, and the host's fix are built and proven there. What
+follows is the original plan, kept for the record.
+
 *mesh-catalog #224, already written. Half a day to assign and prove.*

 **Order.** Assign `zsh` to one server; push; `login-shell.execute@<server> command="uptime"`
@@ -0,0 +1,238 @@
+---
+layer: to-be
+status: in-progress
+code: [mesh-host, mesh-controller, mesh-catalog]
+updated: 2026-10-04
+decisions:
+  - 02-DECISIONS/0203-the-accounts-environment-is-one-modules-and-every-module-contributes-to-it.md
+  - 02-DECISIONS/0204-a-module-contributes-shell-code-to-the-login-shell-in-named-slots.md
+  - 02-DECISIONS/0205-software-the-distribution-does-not-package-ships-as-a-pinned-archive-of-the-module.md
+  - 02-DECISIONS/0176-the-login-shell-is-a-node-seat-and-execute-is-its-contract.md
+  - 02-DECISIONS/0177-a-unit-may-be-user-scoped-and-the-service-manager-is-a-node-seat.md
+  - 02-DECISIONS/0182-inside-a-home-the-mesh-owns-what-it-places-and-holds-the-rest-as-found.md
+---
+
+# 41. The shell and the account's environment
+
+What it takes for the operator's shell to be modules, without a machine losing anything it does
+today. This design replaces the shell half of
+[to-be 38](38-building-the-operators-machine.md) WP5, and finishes the service-manager module of WP6
+short of its user-scoped units. The decisions are [ADR 0203](../../02-DECISIONS/0203-the-accounts-environment-is-one-modules-and-every-module-contributes-to-it.md)
+(the environment), [ADR 0204](../../02-DECISIONS/0204-a-module-contributes-shell-code-to-the-login-shell-in-named-slots.md)
+(shell code and the seat) and [ADR 0205](../../02-DECISIONS/0205-software-the-distribution-does-not-package-ships-as-a-pinned-archive-of-the-module.md)
+(vendored software). The evidence is [research 025](../../01-RESEARCH/025-how-a-module-plugs-into-the-shell/00-overview.md).
+
+## What a node with a shell looks like
+
+```
+ toolchain, agent, …             prompt, plugins, version manager
+        │ environment                     │ shell (zsh, slot)
+        ▼                                 ▼
+ node-environment  ── holds ──  node-env           node-login-shell ── holds ── zsh
+        │                                                 │
+        ├─▶ ~/.config/mesh/environment.sh  ◀─ sourced from zsh's block in ~/.zshenv
+        └─▶ ~/.config/environment.d/50-mesh.conf  ◀─ read by the account's service manager
+                                                          │
+                                       ~/.zshrc: the mesh's block FIRST — defaults and the
+                                       three slots — then the operator's own lines, kept
+```
+
+**The environment module** (`node-env`) holds `node-environment`. It has no package and no process.
+Its two files are written by the host from placeholders the controller fills.
+
+**The shell module** (`zsh`) holds `node-login-shell`. It:
+
+- installs the package;
+- sets the login shell through the `user` shape;
+- writes two blocks:
+  - one in `.zshenv`, sourcing the environment;
+  - one at the start of `.zshrc`, holding the defaults every machine shares today: the title, the
+    keybindings, the aliases and the two small functions, with the three slots in place;
+- contributes its own environment: the editor, the configuration home, and `~/.local/bin` plus the
+  two script directories on `PATH`;
+- serves `execute` and its own `zsh_config`.
+
+**The prompt module** (`powerlevel10k`) ships the theme as a pinned vendored archive, and the prompt's
+configuration as its own file in a directory it owns. It contributes the zsh code that loads both.
+
+**Two plugin modules** (`zsh-autosuggestions`, `zsh-syntax-highlighting`) each install their
+distribution package and contribute one line. Syntax highlighting goes in the `last` slot, which is
+what its upstream asks for.
+
+**What stays the operator's** is everything below the block in `.zshrc`, and `~/.zshrc.local`, which
+the operator's lines source as they do today. On every machine today that means:
+
+- the version manager's lines and the toolchain's `PATH` entry, until those modules exist;
+- the two variables naming the operator's own script library;
+- the agent's title variable;
+- the port aliases;
+- the workstation's desktop variables, which live in `~/.zshrc.local` already.
+
+Nothing is lost at any step, because a line moves out of the operator's part only when a module
+carries it.
+
+**The migration is a person's act**, listed in the zsh module's documentation (ADR 0182): after the
+first push, delete from `.zshrc` the lines the block now carries. Until then they run twice, which is
+harmless and visible.
+
+## Work packages
+
+```
+WP1  the host gives a login back                 (mesh-host)            issue 228
+WP2  the controller composes environment and shell code (mesh-controller)
+WP3  the modules                                 (mesh-catalog)         needs WP2 to resolve
+WP4  the service manager's module, finished      (mesh-catalog)         independent
+WP5  assign and prove                            (operator-gated)       needs WP1–WP3 merged and rolled
+```
+
+WP1, WP2 and WP4 are independent, and are built in parallel on one feature branch per repository
+([playbook 07](../../00-META/process/07-feature-branches.md)). WP3 is written in parallel and proven
+against WP2's controller before anything is published.
+
+## WP1 — The host gives a login back
+
+*mesh-host. Half a day. [Issue 228](../../04-ISSUES/228-a-login-the-mesh-set-is-never-given-back/00-report.md).*
+
+**What changes.**
+
+- The `user` shape records, in its applied record, the login shell it found whenever it changes it.
+- Removing a `user` never deletes the account, whether or not the mesh created it. If the account's
+  shell is still the one the mesh set, and the recorded shell is still executable, the recorded shell
+  is set back. Otherwise the shell is left as it is, and the outcome says why.
+- Before a shell is set, it is refused unless it is executable and listed among the machine's shells.
+  The exception is a shell that refuses logins (`nologin`, `false`): the distribution does not list
+  those, and the controller's own account uses one, so it need only be executable. The refusal fails
+  that resource and leaves the account untouched.
+- A directory the host creates on the way to a file, a block or an archive inside an account's home
+  belongs to that account, the home itself included when the host makes it. A directory that was
+  already there keeps its owner and mode (ADR 0182). Until this, a fresh account's `~/.config` or
+  `~/.local/share` would have been created as root's.
+- Giving the shell back is reported, never fatal. A failed `usermod` on removal is named in the
+  outcome and the record is dropped, because a fatal removal is exactly the wedge issue 228 is about.
+
+**Proof.** The host's tests:
+
+- an undeclared `user` no longer stops the apply;
+- the found shell comes back;
+- a shell changed by a person since is left alone;
+- a missing shell is refused before `usermod` runs;
+- a created account survives its removal.
+
+## WP2 — The controller composes environment and shell code
+
+*mesh-controller. One to two days.*
+
+**What changes.**
+
+- **The seat table.** It gains `node-environment` (node scope, no verbs) and `node-login-shell`
+  (node scope, the verb `execute`). A module may no longer declare a seat named `login-shell` or
+  `node-login-shell`. Both new seats are seeded into a live store by the existing additive seeding.
+- **The manifest.** It gains two contribution fields, each refused at parse when malformed:
+  - `environment`, with `variables` and `path`: a variable name must be a POSIX name and not `PATH`;
+    a value may not contain `$`, a quote, a backslash or a line break; a path entry's place is
+    `start` or `end`;
+  - `shell`: each entry names a known shell, a known slot, and non-empty code.
+- **Composition.** It fills `${environment:posix}`, `${environment:systemd}` and
+  `${shell:<shell>:<slot>}` in the claiming holder's file contents, from every module assigned to
+  the node. The rendering is ADR 0203's and ADR 0204's: module order, a naming line per contribution,
+  `PATH` entries added only when missing. `${machine:…}` in a contributed value is resolved first.
+- **Refusals.** A variable set by two modules on one node is refused, naming both. A placeholder in a
+  module that does not claim the matching seat is refused, both at the catalogue check and at
+  composition.
+
+**Proof.** The controller's tests:
+
+- both environment renderings, byte for byte, from a fixed set of contributions;
+- the POSIX rendering sourced twice by `sh` leaves `PATH` unchanged;
+- slot order and per-shell filtering;
+- each refusal, by name;
+- the seat table carries both seats and refuses a module declaring either.
+
+The catalogue check over the whole catalogue passes.
+
+## WP3 — The modules
+
+*mesh-catalog. One day.*
+
+**What changes.**
+
+- **`node-env`, new.** It claims `node-environment` and declares two owned files: the POSIX file at
+  the path the seat fixes, and the service manager's file, each holding its placeholder. It declares
+  no tools.
+- **`zsh`, rewritten.**
+  - It drops its seat declaration and claims `node-login-shell`.
+  - Its environment moves to a contribution.
+  - It writes a `.zshenv` block that sources the environment file.
+  - Its `.zshrc` block goes at the start and carries today's shared defaults, with the three slots.
+  - It keeps the `user` shape.
+  - `execute` runs `zsh -lc` in the account's home, with the runtime's session words for the user
+    manager. Its timeout is bounded below the runtime's thirty-second call limit; its output is cut at
+    a bound and marked as cut; on timeout it kills the process group.
+  - Tests cover the tool over real child processes and the manifest's shape.
+  - Its documentation lists the one-off migration.
+- **`powerlevel10k`, new.**
+  - The theme is vendored at a pinned upstream release, with its licence, as an archive artifact
+    unpacked into the module's directory under the account's home.
+  - The prompt configuration is today's file, as its own owned file in the same directory.
+  - It contributes the zsh code that loads the theme and the configuration.
+  - Today's file has the instant-prompt cache commented out, so the module does not turn it on.
+- **`zsh-autosuggestions` and `zsh-syntax-highlighting`, new.** Each declares its package and
+  contributes its loader from the distribution's path, in the `normal` and `last` slots.
+
+**Proof.** The controller's catalogue check over the whole catalogue passes. The modules' tests pass.
+A rehearsal composition for a node holding all five shows:
+
+- the `.zshrc` block with the prompt in `normal` and highlighting in `last`;
+- the environment file with the shell's `PATH` entries;
+- the service manager's file.
+
+## WP4 — The service manager's module, finished
+
+*mesh-catalog. Half a day. From the review of 2026-10-04.*
+
+**What changes.**
+
+- System-scope `start`, `stop`, `restart`, `enable` and `disable` escalate with `sudo -n` when the
+  runtime is not root, as the packet filter and intrusion modules do. They name a refusal by how it
+  failed.
+- User scope reaches the account's manager by its runtime directory, which the runtime's environment
+  lacks.
+- A failed `systemctl` is an error, not an empty list.
+- The package resource goes: the service manager is always present, and it collided with the network
+  module's identical declaration on a machine running both.
+- `status` says whether the mesh declares the unit. The restore note is attached only to such a unit.
+- Tests cover a fake runner.
+
+The user-scoped units of mesh-host #72 stay to-be 38's WP6.
+
+**Proof.** The module's tests. Live, after WP5:
+
+- `node-service-manager.units` answers in both scopes on a workstation and on a server;
+- `restart` of a harmless unit answers `ok`.
+
+## WP5 — Assign and prove
+
+*Operator-gated. Nothing here runs without the operator's go-ahead.*
+
+**Order.**
+
+1. Merge WP1 and roll the host.
+2. Merge WP2, and push the controller.
+3. Merge WP3 and WP4, and build the new modules by hand: a new catalogue module's first build is asked
+   for, not automatic.
+4. On one server, assign `node-env`, `zsh`, `zsh-autosuggestions` and `zsh-syntax-highlighting`, and
+   push. Then check:
+   - `node-login-shell.execute@<server> command="echo $PATH"` shows the shell's entries;
+   - `.zshrc` begins with the block;
+   - the operator's lines follow untouched;
+   - the environment file and the service manager's file exist.
+5. The operator deletes the duplicated lines, per the zsh module's documentation.
+6. The other server, then the two workstations, the workstations also with `powerlevel10k`.
+7. Assign `systemd` everywhere, and prove WP4.
+8. Unassign one plugin module on one machine. Its line leaves the block at the next push, and nothing
+   else changes.
+
+The follow-up records to-be 38 names are still owed:
+
+- what a shell module assigned beside the holder does;
+- how a person's own environment variable is a setting rather than a line, once issue 168 closes.
@@ -43,6 +43,7 @@ document is written and this one's status becomes `implemented`.
 | [`32-what-a-module-declares.md`](32-what-a-module-declares.md) | **Proposed.** What a module declares and what the bus derives from it: three namespaces, subjects from local names, queues never declared, the five relationships, and the build-publish-deploy lifecycle on one bus | [ADR 0126](../../02-DECISIONS/0126-a-module-declares-its-own-seats.md), [ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md), superseded by [ADR 0131](../../02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md) (superseding [ADR 0125](../../02-DECISIONS/0125-the-bus-is-the-only-broker.md)), [ADR 0041](../../02-DECISIONS/0041-events-are-a-relationship.md) |
 | [`37-the-operators-machine.md`](37-the-operators-machine.md) | **In progress.** Every configurable thing on a node is a module, the home included; one default per module varied by settings or kept regions; roles a machine has once as seats with tool contracts; one tool runtime per node on the host side | [ADR 0173](../../02-DECISIONS/0173-the-operators-machine-is-the-meshs-and-a-module-is-what-it-declares.md), [0174](../../02-DECISIONS/0174-a-node-varies-a-module-through-settings-and-kept-regions-never-an-edit.md), [0175](../../02-DECISIONS/0175-one-tool-runtime-per-node-serves-every-modules-tools-on-the-host-side.md), [0176](../../02-DECISIONS/0176-the-login-shell-is-a-node-seat-and-execute-is-its-contract.md), [0177](../../02-DECISIONS/0177-a-unit-may-be-user-scoped-and-the-service-manager-is-a-node-seat.md) |
 | [`38-building-the-operators-machine.md`](38-building-the-operators-machine.md) | **In progress.** The work of design 37 as packages: the runtime serves many modules, the controller composes one per node, the console becomes its serving mode, the packet filter moves first, then the shell and the service manager — tested on the live mesh by the operator's decision | [ADR 0175](../../02-DECISIONS/0175-one-tool-runtime-per-node-serves-every-modules-tools-on-the-host-side.md), [0160](../../02-DECISIONS/0160-the-mesh-issues-an-assignments-subjects-and-a-runtime-serves-what-it-is-issued.md), [0149](../../02-DECISIONS/0149-the-live-mesh-is-the-test-bed.md) |
+| [`41-the-shell-and-the-accounts-environment.md`](41-the-shell-and-the-accounts-environment.md) | **In progress.** The shell and the account's environment as modules: an environment module every module contributes variables and `PATH` entries to, shell code contributed to the login shell in named slots, the prompt and plugins as modules, the host giving a login back, and the service manager's module finished | [ADR 0203](../../02-DECISIONS/0203-the-accounts-environment-is-one-modules-and-every-module-contributes-to-it.md), [ADR 0204](../../02-DECISIONS/0204-a-module-contributes-shell-code-to-the-login-shell-in-named-slots.md), [ADR 0205](../../02-DECISIONS/0205-software-the-distribution-does-not-package-ships-as-a-pinned-archive-of-the-module.md) |

 ## Not yet written

@@ -2,7 +2,7 @@
 status: resolved
 opened: 2026-09-26
 located-in: [mesh-controller internal/catalogue, mesh-sdk src/provisioner, mesh-catalog modules/minio]
-fixed-by: 02-DECISIONS/0201-a-provider-declares-what-it-derives-for-each-consumer.md
+fixed-by: 02-DECISIONS/0202-a-provider-declares-what-it-derives-for-each-consumer.md
 amended-design: 03-DESIGN/01-to-be/27-a-module-requires-the-mesh-resolves.md
 ---

@@ -64,7 +64,7 @@ compares it to what the provider will actually create. The one wrong instance wa
  bucket in its own configuration against the one the provider would create is a check that could
  exist today, for any interface, without the mechanism above.

-## Answered, 2026-10-02 — [ADR 0201](../../02-DECISIONS/0201-a-provider-declares-what-it-derives-for-each-consumer.md)
+## Answered, 2026-10-02 — [ADR 0202](../../02-DECISIONS/0202-a-provider-declares-what-it-derives-for-each-consumer.md)

 The channel is the provider's own `serves` block, which may now name the consumer the mesh is
 serving: `${consumer:as}` and `${consumer:as:dns}`. The mesh fills it once, where it knows who the
@@ -0,0 +1,75 @@
+---
+status: open
+opened: 2026-10-04
+located-in: [mesh-host internal/apply, mesh-controller internal/catalogue]
+fixed-by:
+amended-design:
+---
+
+# 225 — A provisioner cannot read the grant secrets since its code left the container, and every consumer of it is unserved
+
+## What was observed
+
+On the control machine, 2026-10-04, found while looking at why one app was restarting:
+
+```
+[mongodb] [provisioner:mongodb-database] mesh_novox_photos: secret not readable yet
+  (/var/lib/mongodb/grants/novox.photos.secret):
+  Error: EACCES: permission denied, open '/var/lib/mongodb/grants/novox.photos.secret'
+```
+
+**4330 times, every five seconds, since 01:30:20.** The consequence is not a log line: the
+provisioner never reads the password, so it never creates the user, so the consumer never
+connects —
+
+```
+UserNotFound: Could not find user "mesh_novox_photos" for db "admin"
+```
+
+— and the app crash-loops. Two consumers on this machine are in that state.
+
+## Why
+
+The grant secrets are what the mesh seals for each consumer and the host unseals beside the
+provider's contributions file. They are written `-rw------- root root`, which was right while a
+module's own code ran in a container as root.
+
+[ADR 0198](../../02-DECISIONS/0198-a-modules-long-running-code-is-launched-by-the-node-runtime-and-reaches-the-bus-through-it.md)
+moved a module's long-running code out of its container and under the node's runtime, which runs
+as the operator's account. The provisioner is now that account; the secret is still root's. The
+timestamps say it exactly: the files are dated 2026-09-26, the first refusal is 01:30:20 on the
+day the runtime rolled.
+
+**Nothing reports it.** The machine applies cleanly and reads as current; the provisioner says
+`secret not readable yet`, whose wording is for a real and ordinary race on the first pass — the
+host has not written the file yet — and which is indistinguishable, in the log, from a permanent
+refusal. Four thousand occurrences of a message that means "wait a moment" is the shape to
+recognise.
+
+## Why it matters beyond this instance
+
+This is every provider that provisions. The grant secret is the one file the sdk's harness reads
+for every consumer, so a provider that cannot read it serves nobody — and says so only in a line
+that reads like patience.
+
+It is also the general question the runtime move leaves: **what the mesh seals for a module is
+owned for the shape that module's code used to have.** Each module whose code moved is a module
+whose files may now be unreadable to it, and ownership is the mesh's to state, not the module's
+to work around.
+
+## What this is not
+
+Not caused by [ADR 0202](../../02-DECISIONS/0202-a-provider-declares-what-it-derives-for-each-consumer.md)
+or [ADR 0189](../../02-DECISIONS/0189-the-store-keeps-what-the-records-name.md), which landed two
+to three hours after the first refusal. Those rebuilt the two affected consumers, which recreated
+their containers and made a silent fault visible as a restarting one. The dates are above.
+
+## Open questions
+
+- Who owns a grant secret now — the module's account, as `secrets-owner` already says for a
+  module's own secrets? Then the host writes it so, and this is a one-line statement in the
+  declaration rather than a convention.
+- Should `secret not readable yet` stop saying "yet" after the first few passes? A message that
+  is right once and wrong four thousand times is a message that hides its own meaning.
+- Which other modules' files did the runtime move leave behind? The sweep is the same question
+  for every path the mesh writes for a module: directories, bundles, received files.
@@ -0,0 +1,58 @@
+---
+status: open
+opened: 2026-10-04
+located-in: [mesh-controller cmd/mesh-controller/collect.go, mesh-controller internal/inventory/collection.go]
+fixed-by:
+amended-design:
+---
+
+# 226 — The store's sweep stops at the first reference recorded with an address, so it collects nothing at all
+
+## What was observed
+
+The first live run of [ADR 0189](../../02-DECISIONS/0189-the-store-keeps-what-the-records-name.md)'s
+sweep, 2026-10-04, printed on every build:
+
+```
+the artifact store kept 127.0.0.1:5100/mesh-tools/build@sha256:0de48cd3…, so nothing more was
+  asked of it: 127.0.0.1:5100/mesh-tools/build@sha256:0de48cd3… is not a reference into the
+  mesh's artifact store
+1681 more to collect; the next build asks again
+```
+
+Nothing is collected, and nothing ever will be. The store holds 1681 artifacts the mesh no longer
+keeps and the feature that exists to remove them is inert.
+
+## Why
+
+Two correct decisions meeting badly.
+
+**A reference recorded before references were kept without an address** is
+`127.0.0.1:5100/<path>@sha256:…` rather than `artifact-store://<path>@sha256:…`
+([04-ISSUES/102](../102-an-address-recorded-at-genesis-or-build-does-not-follow-the-nodes-ports/00-report.md)).
+`LetGo` rightly refuses to compose a delete for a reference whose shape it does not recognise —
+that refusal is what keeps the sweep from reaching something that is not the mesh's.
+
+**The sweep stops at the first refusal**, because "a store that refuses one refuses all of them"
+— deletion disabled, the store down, the network gone — and pushing through would mean a hundred
+identical failures in front of whoever was building something. That reasoning is right for the
+store refusing. It is wrong for *this* record being unreadable.
+
+So one old record, early in the oldest-first order, halts the whole sweep for ever.
+
+## Why it matters beyond this instance
+
+**A guard that cannot tell "I will not ask about this" from "it would not answer" stops the wrong
+amount of work.** The two deserve opposite responses: skip one, abandon the other. Collapsing
+them into "an error" is how a bounded, cautious loop becomes a loop that does nothing — and it
+reports the right number while doing it, which is what made it look healthy.
+
+## What a fix has to settle
+
+- A reference the sweep cannot address is **skipped, and the sweep goes on** — it is a fact about
+  that record, not about the store.
+- `Recorded()` already normalises the old form to the kept one, and is what the rest of the mesh
+  uses for exactly these references. The sweep should normalise before asking rather than refuse.
+- Only a refusal *by the store* ends a sweep.
+- **How it is checked:** a sweep over records holding one address-recorded reference and one kept
+  one collects the second; a sweep against a store that refuses stops at the first.
@@ -0,0 +1,44 @@
+---
+status: open
+opened: 2026-10-04
+located-in: [mesh-catalog modules/photos]
+fixed-by:
+amended-design:
+---
+
+# 227 — The photo app's admin client asks for port 80, which the reverse proxy holds, so it cannot start
+
+## What was observed
+
+Applying the control machine, 2026-10-04:
+
+```
+applying "photos.admin-client": starting container photos-admin-client:
+  failed to bind host port 0.0.0.0:80/tcp: address already in use
+```
+
+Port 80 on that machine belongs to the reverse proxy (`mesh-route-proxy`, confirmed with `ss`),
+which is the whole arrangement: the proxy holds the public ports and every module is reached
+through it. A module that publishes 80 itself can never start beside it.
+
+Everything else on the machine applied; this one resource fails every pass.
+
+## How it surfaced
+
+`photos` had been pinned at a commit from 2026-09-28 and was rebuilt to `main` on 2026-10-04 —
+forced by [ADR 0202](../../02-DECISIONS/0202-a-provider-declares-what-it-derives-for-each-consumer.md)'s
+refusal of its transcribed bucket name. The admin client is one of the changes that came with the
+rest of `main`. The rebuild did not create the conflict; it delivered it.
+
+**A module pinned months behind carries whatever its branch gained, all at once, the first time
+something makes it move.** That is the cost of a pin, and it is paid in full rather than
+gradually.
+
+## What a fix has to settle
+
+- Which port the admin client should ask for, or whether it should be reached through the proxy
+  like everything else and publish nothing.
+- Whether a module declaring a port the machine's proxy already holds should be refused when it
+  is composed, rather than failing on the machine every pass. The mesh assigns ports
+  ([ADR 0038](../../02-DECISIONS/0038-the-mesh-assigns-the-port.md)); a fixed 80 beside a proxy is
+  a statement it could check.
@@ -0,0 +1,52 @@
+---
+status: located
+opened: 2026-10-04
+located-in:
+  - mesh-host
+fixed-by:
+amended-design:
+---
+
+# 228 — A login the mesh set is never given back, and undeclaring one stops the node applying
+
+## What was observed
+
+2026-10-04. Before the shell module of to-be 38 WP5 was assigned anywhere, a review traced what the
+host does with the `user` shape the module declares (the operator account, with the login shell zsh)
+on three events: first assign, a later push, and unassign.
+
+1. **Undeclaring a `user` stops the node applying anything, for good.**
+   - The host's removal has no case for a `user`, so the orphaned record fails with "no way to remove".
+   - Orphans are removed before the declaration's first resource, and that failure aborts the apply.
+   - The record stays in the host's store, so every later apply fails the same way.
+
+   This was reproduced in a throwaway test against the host's code: the apply produced no outcomes,
+   and an unrelated file in the same declaration was not written. Renaming the resource's id has the
+   same effect. A showcase module carries a `user` today and is exposed to it too.
+2. **The shell the account had is never recorded.** [ADR 0176](../../02-DECISIONS/0176-the-login-shell-is-a-node-seat-and-execute-is-its-contract.md)
+   §2 says the host "gives back [the login shell] when the holding moves". The host keeps nothing to
+   give back.
+3. **A login shell is set whether or not it exists.** A failed package install does not stop the
+   resources after it. `usermod --shell` on the distribution only warns about a missing or
+   non-executable shell, and succeeds. The host's read-back compares the user database's string,
+   which matches. So an account can be pointed at a shell that is not there, and console, ssh and
+   display-manager logins then fail. No machine hit this, because zsh was already installed on all
+   four.
+
+## Why it matters beyond this instance
+
+Unassigning any module with a login in it, the case the mesh promises is ordinary, wedges the
+machine's applies until a person edits the host's store. It is the same class of failure as an
+earlier archive that could not be removed: a shape the host can create and cannot take away.
+
+## Located
+
+mesh-host, `internal/apply`: `remove()` has no `user` case, and `applyUser` neither records the shell
+it replaced nor checks the shell it sets. The fix is set out in
+[to-be 41](../../03-DESIGN/01-to-be/41-the-shell-and-the-accounts-environment.md) WP1:
+
+- a removal that never deletes an account;
+- the login shell given back, if it is still the one the mesh set and the recorded one still exists;
+- a shell refused before it is set unless it is executable and listed among the machine's shells
+  (a shell that refuses logins need only be executable, since the distribution does not list it and
+  the controller's own account uses one).
@@ -0,0 +1,61 @@
+---
+status: open
+opened: 2026-10-04
+located-in: []
+fixed-by:
+amended-design:
+---
+
+# 229 — A rollout cannot be followed through the mesh's tools, so an agent goes round them
+
+## What was observed
+
+2026-10-04, rolling out to-be 41. An agent drove the rollout through the mesh's MCP tools: the
+controller seat's `status`, `plans`, `command`, and the forge's merge. Four times it left those tools
+and posted JSON-RPC by hand to the node console's HTTP endpoint with `curl`:
+
+1. **To wait for a plan.** `plans` answers once, with prose. Nothing waits for a plan to reach a tier,
+   finish or fail. An agent's tools cannot be called from a shell loop, so the only way to be told
+   when a plan moved was a background `curl` loop polling the console every twenty seconds and
+   matching the plan's line with `grep`.
+2. **To read `status`.** `status` answers a paragraph of prose (the bus's user list), then a JSON
+   document, both inside one string. Picking out `behind`, `waiting` and `reported` took a script
+   that cut the string at the first brace and parsed the rest.
+3. **To read one module out of `module list`,** whose output was too long to read whole for one line.
+4. **To call a tool that arrived after the agent's session began.** The modules rolled out in that same
+   session added `node-login-shell.execute` and `zsh.zsh_config` to one machine. The agent's MCP
+   connection had been opened before the console moved to discovery ([ADR 0195](../../02-DECISIONS/0195-the-meshs-tools-are-found-by-address-not-announced-whole.md)).
+   It still held the flat catalogue the console announced then, which lacks both the new verbs and the five discovery tools (`mesh_call` among
+   them) the console announces now. Clearing a session does not reconnect its MCP servers, and the
+   console never sends a list-changed notice, so nothing told the client its list was stale. The agent
+   posted `mesh_machine` and `mesh_call` by hand. Reconnecting the server would have given it the
+   discovery tools, which reach any tool by address the moment it exists.
+
+The calls were authorised, because the console is the operator's own surface. But each is a raw call
+the mesh's tools were meant to make unnecessary ([ADR 0154](../../02-DECISIONS/0154-the-meshs-own-verbs-are-the-controller-seats-tools.md)
+puts the controller's verbs behind the seat). Each is also a script that breaks silently when a
+sentence in the prose changes.
+
+## Why it matters beyond this instance
+
+Every rollout an agent drives has the same shape: merge, wait for a plan, push, wait for reports,
+check `status`. When the tools answer only once and only in prose, every agent writes its own poller
+and its own parser. Those are invisible to review, different each time, and wrong the first time the
+wording moves. An agent that cannot wait also tends to act early, which is the opposite of what a
+rollout needs.
+
+## What a fix has to settle
+
+- A way to **wait** on the mesh's own progress. For example, `plans` and `status` could take a plan
+  or node and a bound, and answer when it moves or the bound passes. Or a verb could follow one plan
+  to its end.
+- **Structured answers** from the controller's verbs, with the prose as a field beside the data, not
+  around it.
+- Whether `command`'s generic answer should take a filter, or whether the verbs it is used for most
+  (`module list`, `node show`) deserve verbs of their own.
+- **A client is told when the console's own surface changes.** The console announces `listChanged`
+  and sends the notice when what it lists changes, for example after an upgrade that changes its
+  tools. A long-running session then never keeps a list the console no longer serves. Discovery
+  already makes every module's tools reachable without the list changing.
+
+How each is checked belongs to the record that settles it.
@@ -0,0 +1,87 @@
+---
+status: open
+opened: 2026-10-04
+located-in:
+  - mesh-host
+  - mesh-controller
+fixed-by:
+amended-design:
+---
+
+# 230 — A host that hands over to a newer one loses its report, and a plan waits for it for ever without saying so
+
+## What was observed
+
+2026-10-04, rolling out to-be 41. A new host build and a new controller were merged together. The
+controller's plan built build-agent and sent every machine a fresh declaration, which also delivered
+the new host. Three of the four machines logged, within the same second:
+
+```
+host 4bd7df099757 is delivered; standing aside so the launcher runs it
+applied 546 resource(s)
+applied, and could not tell the mesh: reporting: context canceled
+nox-mesh-host-launch: running /usr/lib/nox-mesh-host/versions/4bd7df099757/nox-mesh-host
+```
+
+The new host came up and waited for its next declaration. The mesh never heard that the old one had
+applied.
+
+The plan then sat at "tier 1 built; waiting for build-agent on [three machines] to be applied", and
+everything the mesh said about it read as healthy:
+
+- `status` showed it as `rolling` with `"late": false`;
+- `plans` printed "for 0s" on every look, so the wait never appeared to grow;
+- the three machines' reports showed `current: false`, which reads like a machine that is merely slow.
+
+Nothing logged, alerted or counted the wait. It was found because a person asked twice for the plan's
+state, and the cause was found by reading a machine's own journal. A push to each of the three machines
+released it: each new host applied and reported, and the plan moved on.
+
+The same day, a second way to lose a report showed up. Assigning modules with tools to a workstation
+changed the bus's user list, which the control machine's declaration carries. Applying it replaced the
+bus's container, which cut every machine off for about fifteen seconds. The control machine itself
+then logged `applied, and could not tell the mesh: reporting: nats: connection closed`. The report was
+lost because the bus restarted under the apply that restarted it.
+
+## Why it matters beyond this instance
+
+**Every genuine host upgrade loses one report.**
+[Issue 163](../163-a-delivered-host-stood-aside-on-every-push-and-reported-nothing/00-report.md) fixed
+the host that stood aside on every push for the version it already ran. It named the mechanism, that
+standing aside cancels the context the report is published with. That fix made standing aside
+happen only for a real new version, but left the mechanism in place. So whenever a host build reaches
+a machine, that apply's report is lost.
+
+**And the mesh cannot tell a stuck wait from a slow one.** A plan that waits on a report that will
+never come waits for ever, and nothing about it changes:
+
+- its age does not grow ("for 0s");
+- `late` stays false;
+- nothing logs, emits an event or alerts.
+
+This is [issue 187](../187-the-mesh-tells-nobody-when-it-stops-working/00-report.md)'s class of fault
+again, *the mesh tells nobody when it stops working*, now in the rollout machinery that every merge
+goes through. The operator's rule from issue 163 applies: if an answer has not come in the time an
+answer takes, something is wrong, and the mesh must say so itself.
+
+## What a fix has to settle
+
+1. **A report survives whatever its own apply restarts.** The host publishes its report and has it
+   acknowledged before it stands aside. It retries a report the bus dropped once the link is back.
+   Failing that, the new host should report the declaration it took over,
+   naming the apply its predecessor finished. A lost report must be impossible, not merely unlikely.
+2. **A plan's wait has an age and a bound.**
+   - "for 0s" must be the real time since the wait began.
+   - A wait past a bound, set by how long an apply takes rather than by a guess, makes the plan
+     `late`.
+3. **Late is said where people and agents look.**
+   - It is said in `status` and in `plans`.
+   - It is logged as a warning by the controller.
+   - It is emitted as an event under the controller seat, so something can alert on it.
+4. **A plan waiting on a machine the mesh has stopped hearing from** says that, by name, instead of
+   waiting. The machine's heartbeat already tells the controller it is alive. A live machine with an
+   unacknowledged declaration is the stuck case itself.
+
+How each is checked belongs to the fix. For the host: a delivered upgrade, applied, is reported. For
+the controller: a plan whose machine never reports turns `late` within its bound, and says so in
+`status`, the log and an event.
Author	SHA1	Message	Date
jochen	0c2eae07c5	Issue 229: the stale tool list is a connection opened before discovery; the fix is list-changed	2026-10-04 11:01:50 +02:00
jochen	f23a71e0d7	Issue 230: a report is also lost when the apply restarts the bus	2026-10-04 11:00:27 +02:00
jochen	9c13c89fa3	Issue 229: new tools never reach an agent's connection, and the console's generic tools are not on it	2026-10-04 11:00:13 +02:00
jochen	2db0ea268d	Issue 230: a host that hands over loses its report, and a plan waits for it for ever without saying so	2026-10-04 10:54:35 +02:00
jochen	8d83d94659	Issue 229: a rollout cannot be followed through the mesh's tools	2026-10-04 10:51:45 +02:00
mesh-admin	a8ffc2b94b	Merge pull request 'Research 025 graduated: ADRs 0203–0205, issue 228, to-be 41 (the shell and the account's environment)' (#351 ) from feat/the-shell-and-its-environment into main	2026-10-04 08:49:36 +00:00
jochen	1dcbdae1c4	Issue 225 → 228: the number was taken on main while this branch was open	2026-10-04 10:30:46 +02:00
jochen	c3ec48f85c	To-be 41 WP1: directories made inside a home belong to its account	2026-10-04 10:30:23 +02:00
jochen	72eda923c7	ADR 0205: the vendored theme's measured size	2026-10-04 10:30:23 +02:00
jochen	c4fedcdbe3	To-be 41 WP1: a shell that refuses logins need not be listed; giving back is never fatal	2026-10-04 10:30:23 +02:00
jochen	0bf70ee8b4	Graduate research 025: the environment and the shell's contributions ADR 0203: the account's environment is one module's (seat node-environment); every module contributes variables and PATH entries, rendered by the controller as a POSIX file and as environment.d. ADR 0204: shell code is contributed to the login shell in named slots, and login-shell becomes the mesh's node-login-shell. ADR 0205: software the distribution does not package ships as a pinned archive of the module. Issue 225: undeclaring a user stops a node applying; the shell is never given back or checked. To-be 41 carries the work packages; to-be 38 WP5 points to it.	2026-10-04 10:30:23 +02:00
jochen	947b85af5e	Research 025: an environment module holds the account's environment The operator's proposal: one module, holding a mesh seat node-environment, is the only writer of the account's environment. It renders contributed variables and PATH entries as a POSIX file shells source and as environment.d for the graphical session. The shell's contribution shrinks to shell code; the shell render-then-service-manager-again positions become options weighed against it.	2026-10-04 10:30:18 +02:00
jochen	ac6c306df3	Research 025: how a module plugs into the operator's shell Opened after the zsh module's rollout (to-be 38 WP5) was stopped: every machine carries the same predecessor-written startup file, the module's block would duplicate it and drop lines, nothing installs the prompt, and execute never reads .zshrc. Weighs how modules contribute environment and shell code, where the operator's own lines go, ordering, and what a contribution is addressed to.	2026-10-04 10:30:18 +02:00
mesh-admin	96df3ccc88	Merge pull request 'ADR 0201 → 0202, and three issues from the night group 8 shipped' (#350 ) from issues/the-night-of-group-8 into main	2026-10-04 02:34:32 +00:00
jschoubben	bc64c5c187	ADR 0201 → 0202, and three issues from the night it shipped The derived-value record is renumbered a second time: the key-value-buckets record took 0201 while this waited to merge, as the bundles record took 0188 before it. Both times free when chosen, taken by the time it landed. cycle.py caught it; three repositories cite this record, so the number matters. 225 — a provisioner has not been able to read its grant secrets since 01:30, when a module's own code left its container and the files stayed root's. Four thousand refusals, each worded as patience, and two consumers unserved. Not from ADR 0202 or 0189, which landed hours later; dates in the report. 226 — the store's sweep stops at the first reference recorded with an address and collects nothing. A guard that cannot tell 'I will not ask about this' from 'it would not answer' stops the wrong amount of work. 227 — the photo app's admin client asks for the port the proxy holds. A module pinned months behind carries everything its branch gained, the first time anything makes it move.	2026-10-04 04:33:45 +02:00
mesh-admin	be4b5777b8	Merge pull request 'Research 024 and ADR 0201: a module keeps its current state in key-value buckets' (#348 ) from feat/module-state-on-the-bus into main	2026-10-04 01:43:34 +00:00
mesh-admin	d882b3568c	Merge pull request 'Group 8: ADR 0201 (a provider declares what it derives, issue 124) and ADR 0189 (the store keeps what the records name, issue 108); issue 202' (#305 ) from feat/the-store-keeps-what-the-records-name into main	2026-10-04 01:30:47 +00:00
jochen	6b4da63261	Research 024: the composed grants, checked against a server once built	2026-10-04 02:50:02 +02:00
jochen	e1b0bbde91	Research 024 and ADR 0201: a module keeps its current state in key-value buckets Events miss a machine that joins after them and replay history where only the latest matters. A module now declares state it owns and reads; the controller creates the buckets, the runtime serves them on the bundle's channel. Designs 32 and 25 amended; grants measured against a running server.	2026-10-04 02:36:59 +02:00