Coherent agent-facing text: one inventory, a CI lint, and protocol friction as a release metric #487

Agents learn the kernel's protocol only from the text it shows them: the brief, each verb's help, refusals, wake messages and kernel notes. That text is written in many places and has drifted (see #484: one verb named end while every help line says "end your turn", and one refusal message used for two opposite situations, with kernel-internal words like "leg").

The cost is measurable. In a recent study (single-agent runs on one benchmark, six author models), the share of runs that hit a protocol refusal and the refusals per run were:

Friction is highest exactly where the agent has the fewest turns to recover, so incoherent text costs research, not just tokens.

Proposal

1. One reviewable inventory. Every agent-facing string (brief sections, verb help and descriptions, refusals, wake and kernel messages) is generated from, or registered in, one module that can be printed and reviewed as a whole.
2. A CI lint over that inventory:
   • one term per concept (verbs, turn vs run, sleep/wake), checked against a small glossary;
   • no kernel-internal vocabulary;
   • every refusal names the next step.
3. Friction as a release metric. The pre-release canary runs report refusals per run by author model; a release that raises it does not ship without an explanation in the release PR.

Related: #484 (end → stop), which is the first concrete fix this inventory would have caught. Planned for 0.4; sequenced with the attempt.py split so the inventory module is designed once.