Files
hq/02-DECISIONS
jschoubben c2a37ab7f8 38 — the mesh assigns the port, and a module does not care
Jochen's call, and the right one: a module cannot choose a port well,
because it is written once and assigned anywhere. Any number it picks is
a guess about a machine it has never seen, and two modules guessing the
same number is not a mistake either of them made.

Writing it up turned up something the issue had missed. The same number
appears three times in every module — the rule set, what a consumer is
told, and what the runtime publishes — and nothing checks that they
agree. They agree today because one person wrote all three. A module
whose `serves` said one thing and whose container published another
would resolve, compose, apply, and hand every consumer a port that
answers nothing.

So the decision is one source with the other two derived, and an
assignment made once and kept, as a credential is.

The part that needed thought is ports that cannot move — mail on 25,
submission on 587. Those become claims, which is what the mesh already
has for what is singular on a machine. Two modules wanting 25 is the
same shape as two wanting the seat, and gets refused by name at
assignment rather than by a container runtime at apply. That makes this
mostly a matter of pointing an existing mechanism at ports.

Left open: whether a module should publish to the machine at all.
Assignment makes publishing safe without making it necessary.
2026-09-01 17:42:27 +02:00
..

02-DECISIONS

Architecture decision records — the "why" trail behind the rules in 00-META and the specifications in 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 A superseded record has its status: changed and gains a pointer to what replaced it — its text is never edited.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). A "decision" small enough to be one line is almost always a rule, and a rule belongs in 00-META/how-we-build.md, where it is enforced and keeps the incident that earned it.

Frontmatter

---
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

What the mesh is

Its tiers, from the bottom up

What runs on them, and how it gets there

How it is built

How it is checked

How we work