What a module must be able to say, measured against 127 that exist

Every manifest in the system being replaced was read and every key
counted, then set against what the new one can express. Three findings
worth more than the table.

**The most-used key was already covered and I expected a gap.**
Depending on another module — 65 manifests, the commonest thing any of
them says — is a requirement naming a module, which already means that
module rather than anything providing the name.

**The largest real gap is tool servers: 56 modules, over half.** A
module can already run one; what is missing is anything saying it offers
tools. That is plausibly a provision rather than new vocabulary, which
would need nothing added — not yet decided, and recorded as undecided.

**The gap most worth closing is health, at seven modules.** The mesh
knows a container is running, which is not whether it answers, and this
project has paid for that distinction twice. An action with a verify is
exactly the right shape and may not arrive over the link, so a module
cannot declare one.

Two things are missing deliberately and say so: stage hooks, because the
link may not carry an action and a module needing setup ships a program;
and flavours, retired in favour of claims.

Config merging is missing and should stay missing. A mechanism that
understands TOML gets asked for YAML, then INI, which is how the thing
being replaced became unholdable.

Also records what the survey found that is not about coverage: manifests
that had stopped matching what was actually brokered, one fact derived
in two places giving two answers, and a live listing returning
credentials in plaintext.

03-DESIGN/01-to-be/README.md

@@ -25,6 +25,7 @@ document is written and this one's status becomes `implemented`.
 | [`13-credentials-and-their-rotation.md`](13-credentials-and-their-rotation.md) | Credentials, and moving them without a consumer holding one the provider does not know about | [ADR 0001](../../02-DECISIONS/0001-mesh-brokers-nodes-host-agents-think.md), [ADR 0009](../../02-DECISIONS/0009-modules-and-the-graph.md) |
 | [`14-model-access.md`](14-model-access.md) | Model access as a provision, and what a licence is bound to | [ADR 0024](../../02-DECISIONS/0024-model-access-is-a-provision.md), [ADR 0009](../../02-DECISIONS/0009-modules-and-the-graph.md) |
 | [`15-the-agent-session.md`](15-the-agent-session.md) | One mechanism started twice — a node's session and the mesh's | [ADR 0004](../../02-DECISIONS/0004-a-node-and-how-it-joins.md), [ADR 0026](../../02-DECISIONS/0026-the-mesh-has-a-session-of-its-own.md) |
+| [`16-module-coverage.md`](16-module-coverage.md) | What a module must be able to say, measured against 127 that exist | [ADR 0009](../../02-DECISIONS/0009-modules-and-the-graph.md), [ADR 0005](../../02-DECISIONS/0005-the-node-host.md) |
 
 ## Not yet written