/map-build-layer

/map-build-layer — generate one zone's drill-down layer (E3/E4)

/map-build produces the top-level map. This command produces the generated layer for a single zone (PRD-076 FR-4): a scoped SCAN→EXTRACT→ VERIFY→EMIT→VALIDATE pass restricted to that zone's subtree, emitting the zone's own sub-map (its own zones/nodes/edges/flows/description_ru) — so descending into the zone in forgeplan-web shows an emitter-generated architecture map, not just the client-derived un-hiding of raw children.

Append-only and EMITTER-safe: same denylist + map-emitter-gate.sh + guardian single-write controls as /map-build — it writes only the layer output, never mutates a forgeplan artifact.

What to do

1. Parse the target. $ARGUMENTS is "<zone-id>" [repo-root]. The zone id may be nested ("z.core/z.entities") for deeper recursion — the last segment is the zone to build, the earlier segments are the ancestor layer path. Resolve the repo root as /map-build does (arg or cwd).

2. Preconditions. Confirm <repoRoot>/.forgeplan/map/map.json exists (the top map must be built first — if not, tell the user to run /map-build first) and that the named zone id is present in it (or in the named ancestor layer). If the zone doesn't exist, stop and name the valid zone ids.

3. Dispatch the orchestrator in SCOPED mode — one Task call:

   Task(subagent_type="forgeplan-map-pack:map-orchestrator",
        prompt="SCOPED LAYER build for zone '<zone-id>' of the repo at <repoRoot>. "
             + "Read the existing .forgeplan/map/map.json, take the target zone's member "
             + "nodes as the seed set, and run a SCOPED SCAN (restricted to those members' "
             + "real paths/subtree) -> EXTRACT -> VERIFY -> EMIT -> VALIDATE producing a "
             + "sub-map for THIS zone only: its own zones (the sub-regions inside it), nodes, "
             + "edges, flows, and description_ru, at the same E1/E2 quality bar as the top map. "
             + "ROLE DECOMPOSITION IS MANDATORY (see the orchestrator's Scoped-pass rules, findings B+C): "
             + "zone-extractor writes the scoped .extract.json (repo_head + project at TOP level) AND "
             + "persists the scoped .composition.json; edge-verifier writes the scoped .edges.json "
             + "({typedLink,codeDep} with id+namespace); map-emitter decides ONLY the flows and runs "
             + "map-emit.mjs --layer. map-emitter MUST NOT self-author the scoped extract/edges/composition. "
             + "Write it as the zone's layer (see the layer contract below), NOT into the top "
             + "map.json's node set. Enforce gates G1-G4 on the scoped scratch. Deeper recursion: "
             + "if the target was '<ancestor>/<zone>', seed from the ancestor layer, not the top map.")
   

4. Layer output contract (coordinate with forgeplan-web). The layer is written as a sibling file: .forgeplan/map/layers/<zone-id>.json, itself a valid forgeplan.map/v1 document (same schema, same guardian checks). forgeplan-web's deriveSubDocument seam (RFC-031) fetches this generated layer on descend when it exists, and falls back to its client-derived un-hide when it doesn't — so the layer degrades gracefully and needs no web change to be safe, only a small seam change to be rendered. (This is the one cross-repo contract decision PRD-076 FR-3 flags — inline layers[] vs sibling file; this command ships the sibling- file shape.) Nested layers write to .forgeplan/map/layers/<ancestor>/<zone>.json.

5. Report: which zone, how many sub-zones/nodes/flows the layer has, whether the guardian confirmed it, and the layer file path. If the zone is thin (few members), say so — a shallow zone may not warrant a rich layer.

Notes

• Local, headless-only (same as /map-build). Headless: claude -p '/map-build-layer "z.core"' --add-dir <repo> --allowedTools Read Glob Grep Write Task.
• The UI can surface this command. On a zone with no generated layer yet, forgeplan-web can show a copy-command hint (like the empty-state that suggests /map-build); running this command + a poller refresh makes the layer appear.
• Deterministic + append-only. Content-hash ids, no x/y, recursively. Re-running on an unchanged zone is idempotent.