# Skill: Maintenance Due

Use this skill when a human talks about maintenance, service intervals, odometer/hours, "is it due?", or logging completed work. Stay in chat. This site is not a CMMS UI.

Do not invent OEM intervals. Do not rewrite history. Do not call JSON "legacy."

## 1. Load the contract

1. `GET /health` — confirm the origin is this Worker.
2. `GET /skill.md` (or `GET /muse/skill.md`) — you are here.
3. `GET /openapi.json` (or `GET /api/openapi.json`) — live routes. Do not invent paths.

## 2. Tenant = personal bearer token

1. If you have **no** token: `POST /api/v1/bootstrap` with **no** `Authorization` header.
2. Optional body `{ "seed": true }` loads Truck A (oil change: 5000 miles OR 200 engine hours, whichever first).
3. Store `token`. Plaintext is shown once. The token **is** the tenant.
4. Every later `/api/v1/*` call: `Authorization: Bearer <token>`. **Never send userId.**
5. Wrong bearer → `401`. That does **not** mint a second account. Do not retry bootstrap just because a call failed auth.
6. Bootstrap is rate-limited. On `429`, honor `Retry-After`. Errors are `{ code, message, retryable, hint? }`. Retry only if `retryable` is true.

## 3. Due-engine loop (do in order)

1. **What's due?** `GET /api/v1/agent/due` — Markdown, `Content-Type: text/plain`. Prefer this over JSON.
2. **Need structure after a write?** `GET /api/v1/due` or `GET /api/v1/due.md`. Same tree, not a second API.
3. **New thing:** `POST /api/v1/things` `{ "name", "type?", "notes?" }`.
4. **New service + explicit rule:** `POST /api/v1/things/:id/services` with `name` and optional `rule` / `expression`. If they did not state an interval, **do not write a rule**.
5. **Meter observation:** `POST /api/v1/things/:id/readings` `{ "meter", "value", "observed_at?" }`. Append only.
6. **Job done:** `POST /api/v1/services/:id/events` `{ "completed_at?", "parts?", "notes?" }`. This resets last-done. History grows.
7. **History:** `GET /api/v1/agent/things/:id` (text/plain) or `GET /api/v1/things/:id/history.md`.
8. Re-check due. Completions clear due. The engine never invents the next interval.

## 4. Expression grammar (write only what they stated)

- Calendar: `{ "op": "calendar", "every_days": N }` — days since last completion, else service `created_at`.
- Meter: `{ "op": "meter", "meter": "miles", "every": N }` — latest minus reading at last completion (else created, else 0). No reading → not due.
- OR: left-to-right; **first hit wins**. Classic demo: 5000 miles OR 200 engine hours.
- AND: all children required. Nesting is allowed.

## 5. Hard stops

- Never PATCH/DELETE readings or events. Those routes return `405 append_only`.
- Never delete a thing/service that already has a log (`409`).
- `GET/POST /mcp` is reserved Streamable HTTP (stateless; no sticky `Mcp-Session-Id`). Day-1 stub only — do not POST JSON-RPC yet.
- Do not touch fluidrecall.com, TimesOwl, Heidi, or any Fluid Recall Worker/D1/secrets.

## 6. Catalog

Writes are JSON `/api/v1`. Agent reads are `GET /api/v1/agent/*` as `text/plain`. Full list: `GET /api/v1/agent` or `GET /llms.txt`.