Cosmix Self-Aware Layer — Spec Distribution and Capability Discovery

Split out of SPEC 07 §5 (2026-06-05). A distinct subsystem from the observability contract: how an agent fetches the specs themselves over ABP (spec.get, the world.specs.* retained topics, the SPEC universal command, the agent bootstrap sequence) so it can join a mesh with no out-of-band docs. Implemented + live (spec.get, world.specs.*). Section numbers are preserved as §5.x so existing "SPEC 07 §5.x" cross-references resolve here.

5. Spec Distribution and Capability Discovery

This section is the canonical Tier 1 spec-distribution contract. The live broker implementation is $COSMIX/src/crates/cosmix-noded/src/spec.rs plus the retained world.specs.* publisher in noded.rs. It is the bootstrap path for any agent joining the mesh.

5.1 spec.get broker command

The broker (cosmix-noded) MUST implement spec.get:

---
amp: 1
type: request
to: noded
command: spec.get
args: {"chapter": 1}
---

Response: the spec chapter as a full ABP message — its frontmatter as headers, its body as the body. The same parser that handles wire messages handles spec delivery; specs and ABP messages share a format by construction (Ch 01 §6).

args accepts either {"chapter": <int>} or {"name": "<filename>"}. If neither matches a chapter under _spec/, response is rc: 10 with an error body listing the available chapters.

5.2 world.specs.<n> retained topics

The broker MUST publish each spec chapter as a retained topic named world.specs.<n> (e.g., world.specs.01, world.specs.07). New subscribers receive the current spec immediately. Spec edits trigger republish.

5.3 SPEC universal command

A daemon MAY implement the SPEC universal command (extending Ch 02 §3):

---
to: maild
command: SPEC
---

Response body: the spec section relevant to the daemon's protocol surface (typically a subset of the relevant chapter). Daemons whose entire surface is covered by a single chapter return that chapter via spec.get rather than duplicating content; SPEC is for daemons whose contract spans multiple chapters or carries daemon-specific extensions.

5.4 Agent bootstrap sequence

A fresh agent joining the mesh:

1. noded.ping — confirm liveness, read extensions map (Ch 03 §2.6).
2. spec.get chapter=1 — wire protocol.
3. spec.get chapter=2 — command vocabulary.
4. spec.get chapter=7 — this chapter, the introspection contract.
5. noded.list — enumerate registered services.
6. For each service: <svc>.HELP, <svc>.INFO, <svc>.props.list, <svc>.props.describe path=<each> — build the local model.
7. Subscribe to world.* — receive live state.

No SDK, no schema repository, no out-of-band documentation. The protocol is self-describing over itself. This is the realisation of the mandate's "legible to agents" criterion at the wire level.

---