cos: Skill for Claude Code

Body MCP setup (thin fetch-wrapper bridge :8012)

Why this exists / architecture

body is the foundational built-in add-on — the single owner of body identity (sex / date of birth / height / training status / whether you lift), the weight + body-composition series, and the free-text objective (the goal). Nutrition & Chef and Fitness both read it cross-add-on (current weight, target, training status, the goal). Like nutrition and fitness, it has no external repo and no sidecar: the server lives in this Cos checkout at mcp/body-server/server.mjs, the same thin fetch wrapper archetype over the board's /api/body/* HTTP routes on CRM_BASE_URL. It makes no LLM calls — the board serves deterministic physiology facts via /api/body/status (BMR / TDEE / BMI / trend / fat-free mass), but it never computes a recommendation; the daily targets are authored by the agent (the nutrition-chef skill → save_nutrition_targets).

Every write is add-on-gated — attributed to the agent via the x-actor header and blocked only when the add-on is disabled. It is a single Node stdio process and registers into Cos the same two ways the core servers do:

• Claude Code reaches it over HTTP via a supergateway + launchd BRIDGE on :8012 ($BODY_BRIDGE_PORT, label com.chiefofstaff.mcp-body, IN .mcp.json).
• Claude Cowork Desktop spawns it as a direct stdio command entry in claude_desktop_config.json.

Claude Code   ──HTTP──> localhost:8012/mcp ──supergateway(launchd)──> node body-server (stdio)
                                                                          │ fetch (x-actor:agent)
                                                                          └──HTTP──> board /api/body/* (:3000)
Cowork Desktop ──spawns stdio directly──────────────────────────────────> node body-server   (§5)

This add-on HARD AUTO-ENABLES — it is usually already on. Unlike nutrition/fitness (which ship disabled and need a manual toggle), body auto-enables in the same write whenever Nutrition or Fitness is enabled (a hard dependsOn cascade in /api/addons/[id]), because both consumers read body identity and are meaningless without it. So once you've enabled a consumer, body is on. It can also be enabled directly. Conversely, body refuses to be disabled (HTTP 409) while a hard consumer (Nutrition/Fitness) is still enabled — disable the consumer first. Its writes are GATED and its reads are open exactly like the other add-ons; a disabled body 404s every write (Not found.) and hides/404s the /body page.