D1182 — The managed instructions block is brief by default

Amended by D1246: the routed kb clause of the routing sentence is shortened, so the sentence is no longer kept verbatim; the routed 9-KB block is capped at 8192 bytes.

Decision. Each KB's region of the managed block carries its routing sentence, its archives and the names of its valid skills (sorted, at most 40, then +<n> more (kb_guide)). The operational bullets are written once per block by the client, after the last region, with one rule (procedures, runbooks and incidents are read whole with concept_read) and one line saying kb_guide returns the full guide, each KB's own directives and its skills on demand. A KB keeps its instructions.md in the block only by declaring <!-- cartographer: block: full --> on the leading lines of the file; preamble: none still means "no generated operational text" and the brief region of such a KB starts with the single comment <!-- cartographer: preamble: none --> so the client can tell. status and sync warn when a block is over 16 KiB (bytes/4 tokens, approximate); the warning informs and changes no state or exit code.

Why. The block is paid on every model call of every session and grew linearly with the bound KBs: nine KBs measured at 40.7k tokens per call, one at 3.0k, against 0.23k for the routing sentence and four lines pointing to kb_guide. A brief block without the skill names and without the "read whole" rule loses the procedures (6/12 on procedure tasks against 12/12 with both), which is why the names and the rule stay.

Alternatives rejected. A global "full" mode or a .cartographer.yaml key or server flag: a second place to set it, and the client does not hold the curated text (the server builds the artifact). The per-KB directive travels with the KB and needs no key. Dropping the skill catalog: loses the procedures. No cap on the catalog: one skill-rich KB would defeat the budget. A configurable warning threshold: one constant is enough and cannot be mis-set.

Consequences. The ContentHash of every instructions artifact changed once, so every client re-syncs and rewrites its block a single time on upgrade. The shared section is client-owned text with no artifact hash: it is folded into the hash the lockfile records for the client-written tail (PathsSectionHash), which rewrites the block once after a release that edits it and then converges. Mixed versions degrade and never break (a new client skips its shared section when a region already carries Operational instructions:; an old client writes the brief regions without bullets until upgraded). Known mixed-version limitation: a new client against an old server where every KB opted out with preamble: none writes the shared section, because the old server sends no marker comment and no Operational instructions: line; the next server upgrade removes it. Directive collisions (D183) are scoped to what is in the artifact: two brief KBs may declare different values for one key, each being read through kb_guide one KB at a time; block: full KBs still collide. A KB whose directives must be in every session adds the block: full line (release note). The routing sentence naming every KB of a connection is kept verbatim (it is what the 12/12 measurement used).

Measured budgets, pinned by TestBlock_Budget (measured size plus at most 10 %, with a hard cap): 5 archives and 12 skills per KB, none block: full, the written block is 3377 bytes for one KB and 6801 bytes for nine (about 0.85k and 1.7k tokens; the local-paths paragraph is about 0.9 KiB of it); the shared section alone is 2146 bytes and one brief region 357 bytes. The end-to-end fixed-cost budget (block plus tools/list) is #1206's, which may tighten these but not loosen them.