Files
hq/02-DECISIONS
jschoubben 4866007c04 ADR 0038 accepted; ADR 0039 (proposed) — the link is the security boundary
0038 accepted: no two modes. One behaviour, two sources of declaration.

0039 fills the gap 0038 named. Proposed rather than measured — it designs a
boundary that does not exist — but what it replaces IS measured, and that is the
argument.

Today adopt.sh asks the operator to paste in the postgres password and the
object store password, the same ones on every node, and they are not discarded
after adoption: wireguard and traefik open a pg connection on every reconcile.
So every node permanently holds a credential to the control plane's database,
and 00-as-is/06 records that nothing rotates it. Compromise of any node is
compromise of the mesh's store, with no way back.

Four properties make the link a boundary rather than a pipe: it is outbound and
node-initiated, so a node has no listening control surface — which the topology
already requires, since most nodes have no forwarded port. A node holds its own
identity and nothing else, so compromise of a node is compromise of that node.
Authority is mutual, because a host that applies whatever the link delivers must
know the mesh from something impersonating it. And what may be pushed is bounded
by FORM — declarations of known shape, never a command to run.

That last property is stated with its limit rather than oversold: it bounds
form, not impact. A compromised control plane can declare harmful state and the
host will apply it faithfully. What it buys is a describable blast radius.

Joining uses a one-time short-lived enrolment token, useless once used and
useless after a while, in place of hand-carried shared secrets.

Named rather than hidden: the first node's identity is self-issued and becomes
the root of trust, which is the one place 0038's "no special first node" does
not fully hold. Rotation becomes possible and is still not designed. And what
may expire is constrained by 0036 — an identity needing refresh would make a
laptop fail for being a laptop.
2026-08-25 22:27:31 +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 A superseded record has its status: changed and gains a pointer to what replaced it — its text is never edited.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 0026). 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

The index is generated, not maintained — run the hq-status skill, which reads the frontmatter of every record. A hand-written index drifts from the folder it describes, and this one had already done so after a single addition.