novox/hq

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T

jschoubben 702efca6bb Base layer: the mesh as it is, under the mesh as it should be

HQ held only the to-be. Every reader had to already know the system the
decisions were about, and an as-is claim had nowhere to live except inside
an intention.

Adds 02-DESIGN/00-as-is — eleven documents written from the implementation
and the operational record, not from intent, including the parts nobody
would choose again. The two existing designs move under 01-to-be. Layers
are declared in frontmatter and never mix: a design that ships does not
move, its as-is counterpart is written, and both stand.

Back-fills adr/0001-0014 for decisions taken in implementation and never
recorded — the broker, the module abstraction, the mesh database, managed
files, provisioning, migrations, the workspace removal, failing loudly,
the constitution, application placement, linking, the employee model, the
artifact, the three silos. Each marked reconstructed, dated from the
history, and citing the evidence it was recovered from. The two existing
records renumber to 0015 and 0016 so the ledger runs oldest first;
0017 extends 0015 to modules outside the core, principle only — the
domain list is deliberately not invented here.

how-we-build.md becomes the source of the mesh constitution, with a sync
playbook, so the enforced copy stops being the only one that is true.

Process becomes explicit: five playbooks, eight thin skills that defer to
them, a repository map, and AGENTS.md with CLAUDE.md as its include.

The five Observations become 04-ISSUES 001-005 where they can be owned and
closed. 006 is new and uncomfortable: HQ is not indexed into the knowledge
base. That claim is what decision 27 rests on, it was never checked, and
the README now says so instead of repeating it.

Also corrects the ADR index into something generated, the "02-DESIGN is
empty" claim, the VISION.md pointer that did not survive the repo split,
and a note asserting the symlink rule was contradicted — it was a
misreading; the rule forbids hand-made links, the installer links by design.

2026-08-23 03:08:26 +02:00

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status, date, deciders, reconstructed

status	date	deciders	reconstructed
accepted	2026-02-25	jochen	true

1. Nodes communicate over a message broker, not over HTTP

Reconstructed after the fact from the evidence cited below. The decision was taken in implementation, not in a record; this document states what was decided and why, not a deliberation that happened.

Context

The mesh is a set of machines that must call each other's capabilities. On the day the repository was founded there was no inter-node transport at all — each node was configured independently and shared nothing at runtime.

Three properties were required and are visible in everything built since:

A node behind a household NAT must participate fully. It can dial out; nothing can dial in.
A node that is asleep, rebooting or upgrading must not cause a caller to fail — the request should wait, not error.
Adding a node must not require editing anything on the nodes that already exist.

Considered options

HTTP APIs between nodes. Rejected. Every node becomes a server that every other node must be able to reach, which the NAT case makes impossible without inbound tunnels to each participant. It also makes node liveness a caller's problem: a request to a sleeping node is an error rather than a wait.
Polling a shared database. Rejected. Latency is the poll interval, load is constant and independent of demand, and request/reply has to be built on top of it by hand.
A central message broker with per-node exchanges. Chosen.

Decision

All inter-node communication goes through a message broker. Every node owns a topic exchange named for itself and a request queue; a shared mesh exchange carries commands and events that are not addressed to one node.

Three message shapes, and only three:

RPC — request/reply, for calling a capability that lives on another node.
Commands — instructions to do a stage of work, addressed by what is to be done.
Events — statements that something happened, addressed to nobody.

Every node dials the broker outbound. Nothing dials a node.

Consequences

NAT stops being an architectural concern. A node's reachability is a property of the broker connection, not of its network position.
A call to a node that is down waits in that node's queue instead of failing. This is usually right and occasionally the wrong thing entirely — a queued command for a node that never returns is a stall with no error, which is the failure shape this mesh keeps rediscovering.
The broker is a single point of failure and a single point of trust. Its credential is mesh-wide, so rotating it is a mesh-wide operation.
Tools never leave the host: a remote call proxies over the broker and the credentials stay where the capability is.

References

The broker was stood up on 2026-02-25, the second day of the repository.
Knowledge base: mesh (transport, exchanges, queue naming), troubleshooting/amqp-credential-rotation.
The stall shape is recorded in troubleshooting/empty-pipeline-blocks-the-queue and troubleshooting/daemon-and-tool-server-share-a-request-queue.

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