Files
hq/02-DECISIONS/README.md
T
jschoubben e4327a3a5e Phase 1.3 done: ordering was already there, the network was not
Ordering needed no change for the third time running — resources apply
in the order declared and nothing sorts them — and is now asserted,
because sorting them for any sensible reason would have passed every
other test.

Separates ordering from readiness, which the task had run together: a
container started is not a container ready. Nothing waits, and what
needs something usable retries. That is deliberate and more robust than
start ordering, since a dependency can restart long after apply.

The network was the first thing in Phase 1 that genuinely needed
building, and the first that needed a decision: 0029 records why a shape
rather than an action, and the vocabulary is nine.
2026-08-31 18:55:22 +02:00

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# 02-DECISIONS
Architecture decision records — the "why" trail behind the rules in
[`00-META`](../00-META/) and the specifications in [`03-DESIGN`](../03-DESIGN/).
**Numbered `02` because a decision precedes the design it authorises.** Research concludes,
the decision is recorded here, and only then is the design written. Following the folder
numbers walks the process in the order it happens.
One file per decision, numbered, never deleted. A superseded record has its `status:` changed
and gains a pointer to what replaced it — **its text is never edited**. The reasoning that was
rejected is the expensive half to rediscover.
The records run in the order the decisions were taken, oldest first.
**Every decision is a record.** There is no ledger and no index file — if a decision is worth
recording it is worth a record, and if it is not worth a record it is not recorded
([ADR 0019](0019-how-this-repository-works.md)). A "decision" small enough to be one line is
almost always a **rule**, and a rule belongs in
[`00-META/how-we-build.md`](../00-META/how-we-build.md), where it is enforced and keeps the
incident that earned it.
## Frontmatter
```yaml
---
status: proposed | accepted | superseded
date: YYYY-MM-DD # when the decision was taken, not when it was written down
deciders: name
reconstructed: true|false # true when the record was written after the fact from evidence
superseded-by: # 02-DECISIONS/NNNN-....md, when status is superseded
extends: # 02-DECISIONS/NNNN-....md, when this record widens an earlier one
---
```
## Body
```
# N. Title in plain language
## Context what was true, with evidence
## Considered Options numbered, each with why it was rejected
## Decision what was decided
## Consequences what follows, including what got harder
## References commits, pull requests, knowledge-base entries, prior art
```
State evidence, not assertion. *"Zero of 124 modules declare `brain` as a dependency"*
outranks *"the dependency rule is not followed"*.
## Reconstructed records
Records 0001–0014 were written on 2026-08-23, after the decisions they describe. Records 0015 onward were taken as records. Those
decisions were taken in implementation rather than in a document; the records state what was
decided and the evidence it was decided from, and each carries `reconstructed: true` and says
so in its first lines.
A reconstructed record is not a transcript. Where the deliberation is not recoverable, the
options section states what the alternatives were and why the chosen one won on the evidence
available — not a discussion that did not happen. Where a date is not establishable it says so
rather than guessing.
## Index
**A number identifies a record and never changes.** Records are referenced from outside this
repository — code comments, commit messages — so a number that moves invalidates them silently.
Renumbering once cost 96 references across two code repositories, and that is why the numbers
are now fixed.
So the folder is in creation order, and **the reading order lives here.** It is generated from
each record's `topic:` and written, because a reader looking at the folder on a forge sees the
folder rather than a command. The objection to a written index is that it drifts — which is
answered by checking it rather than by refusing to write one:
```
python3 00-META/checks/index.py --write regenerate
python3 00-META/checks/index.py fail if stale
```
<!-- index:start -->
### What the mesh is
- **0001** — [The mesh brokers capabilities; nodes host; agents think](0001-mesh-brokers-nodes-host-agents-think.md)
- **0002** — [Nodes communicate over a message broker, not over HTTP](0002-nodes-communicate-over-a-broker.md)
- **0003** — [An agent is a persistent employee, not an instance of a pool](0003-agents-are-persistent-employees.md)
### Its tiers, from the bottom up
- **0004** — [A node, and how it joins](0004-a-node-and-how-it-joins.md)
- **0005** — [The node host](0005-the-node-host.md)
- **0006** — [The substrate and the control plane](0006-the-substrate-and-the-control-plane.md)
- **0007** — [Connectivity](0007-connectivity.md)
- **0008** — [A context owns its store, exclusively](0008-a-context-owns-its-store.md)
- **0028** — [The substrate supplies the control plane and nothing else](0028-the-substrate-supplies-the-control-plane-and-nothing-else.md)
- **0029** — [A network is a shape, because an action cannot be undone](0029-a-network-is-a-shape-because-an-action-cannot-be-undone.md)
### What runs on them, and how it gets there
- **0009** — [Modules and the graph](0009-modules-and-the-graph.md)
- **0010** — [Delivery](0010-delivery.md)
- **0024** — [Model access is a provision, and a licence is a thing with a name](0024-model-access-is-a-provision.md)
- **0026** — [The mesh has a session of its own, and it is the node session's mechanism](0026-the-mesh-has-a-session-of-its-own.md)
- **0027** — [A provision names what the consumer is coupled to, not the role it plays](0027-a-provision-names-what-the-consumer-is-coupled-to.md)
### How it is built
- **0011** — [Managed files are generated onto nodes and never edited there](0011-managed-files-are-generated-never-edited.md)
- **0012** — [The mesh creates no symlinks — a derived file is a copy](0012-the-mesh-creates-no-symlinks.md)
- **0013** — [Schema and state changes are numbered migrations, in the same language as the code](0013-schema-changes-are-numbered-migrations.md)
- **0014** — [No workspace — each module is a standalone package consuming published dependencies](0014-no-npm-workspace.md)
- **0015** — [Applications live in their own repository; the monorepo is for the mesh](0015-applications-live-in-their-own-repository.md)
- **0016** — [The lab](0016-the-lab.md)
### How it is checked
- **0017** — [A test defends a decision](0017-a-test-defends-a-decision.md)
- **0018** — [A picture of a system is read from the system, never from what asked for it](0018-a-picture-is-read-from-what-runs.md)
### How we work
- **0019** — [How this repository works](0019-how-this-repository-works.md)
- **0020** — [The mesh is governed by a constitution, injected where work is decided](0020-the-mesh-is-governed-by-a-constitution.md)
- **0021** — [HQ is the source of the mesh constitution](0021-hq-is-the-source-of-the-constitution.md)
- **0022** — [The constitution absorbs what is already enforced](0022-the-constitution-absorbs-what-is-enforced.md)
- **0023** — [The approval is the checkpoint, not the second pair of hands](0023-approval-is-the-checkpoint.md)
- **0025** — [The design record is read where it is written, never copied to be found](0025-the-design-record-is-read-not-copied.md)
<!-- index:end -->