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---
name: writing-plans
description: The spec-to-plan bridge. Routed to by /feature once the brainstormed spec is approved, and by /sprint before execution. Decomposes the spec into 2–5 minute tasks, each carrying its exact file path(s) and a concrete verification step that maps to a tdd obligation. Writes the plan to .codearbiter/plans/<slug>.md, ordered with dependencies flagged and an MVP slice identifiable. Nothing executes until every task has a path and a verification and the task set covers every acceptance criterion.
---
# writing-plans
Turn an approved spec into an executable plan. Routed to by `/feature` (after spec approval) and `/sprint`.
## Pre-flight
Read these, or STOP and surface the gap — never plan against an unapproved or missing spec:
- `<project-root>/.codearbiter/specs/<slug>.md` — the approved brainstorming spec. The single source of acceptance criteria. Absent or unapproved → STOP and route back to `/feature`.
- `<project-root>/.codearbiter/CONTEXT.md` — the `stage:` frontmatter (the maturity value) and project context.
- `<project-root>/.codearbiter/tech-stack.md` — file layout, build/test/lint invocations. A verification step cites a real command from here, never a guess.
- `<project-root>/.codearbiter/coding-standards.md` — structure and naming, so a task names the right path.
**If `--farm` was requested:** check that `FARM_API_KEY` is set in the environment (or `.env` at `${CLAUDE_PLUGIN_ROOT}/tools/.env`). If absent, BLOCK immediately — cite `${CLAUDE_PLUGIN_ROOT}/includes/farm.md` for setup instructions. Do not proceed; the farm dispatcher cannot run without an API key. Model selection happens later (at dispatch time in `subagent-driven-development`), so no model research is needed here.
## Phase 1 — Criterion extraction · gate: BLOCK
Lift every acceptance criterion from the spec verbatim and assign each a stable ID (`AC-01`,
`AC-02`, …). This list is the coverage ledger for the whole plan — Phase 4 checks the task set
against it.
A criterion the spec leaves ambiguous is a `[CONFIRM-NN]` against
`<project-root>/.codearbiter/open-questions.md` — surface it, do not invent the intent.
Gate: every acceptance criterion in the spec captured as a numbered `AC-NN`. A partial ledger does
not pass.
## Phase 2 — Task decomposition · gate: BLOCK
Break the work into the smallest honest units. Each **task** is ~2–5 minutes of work and carries:
- **id** — `T-01`, `T-02`, … stable.
- **path(s)** — the exact file(s) the task touches, resolved against `coding-standards.md`. "Some files" is not a path.
- **verification** — one concrete command or observable that proves the task done (e.g., `<test cmd> -k test_token_expiry passes`, `endpoint returns 401 on missing header`). It cites a real `tech-stack.md` invocation or a directly observable behavior — never "looks right".
- **maps-to** — the `tdd` obligation this verification corresponds to. The verification *maps to* a tdd obligation; it does NOT replace tdd's own gates. `tdd` Phase 1 still derives and Phase 4 still verifies obligations against passing tests.
- **covers** — the `AC-NN`(s) this task advances.
Split anything that won't fit ~5 minutes or touches unrelated paths. Reject the trap of one
monolithic "implement the feature" task — that defeats the plan.
Gate: every task has at least one path AND a verification AND a `maps-to`. A task missing any of the
three blocks the plan.
## Phase 3 — Order & MVP slice · gate: BLOCK
Order tasks so each runs only after what it depends on. Flag every dependency explicitly
(`T-07 depends on T-03`). A cycle is a decomposition error — return to Phase 2 and split.
Group the ordered tasks so the **MVP slice** is identifiable: the minimal contiguous task set that
satisfies the spec's core acceptance criteria and is shippable on its own. Everything past the slice
is incremental.
Gate: a complete dependency order with no cycle, and an explicitly marked MVP slice.
## Phase 4 — Coverage proof & write · gate: BLOCK
Cross the ledger against the task set, both directions:
- Every `AC-NN` is covered by at least one task's `covers`. An uncovered criterion blocks — author the missing task.
- Every task advances at least one `AC-NN`. A task that covers nothing is scope creep — cut it or surface it.
Then write the plan to `<project-root>/.codearbiter/plans/<slug>.md` — `<slug>` matching the
spec — with the `AC-NN` ledger, the ordered task table (id · path(s) · verification · maps-to ·
covers · depends-on · **status**, initialized `PENDING`), the marked MVP slice, and any out-of-scope
item tagged inline `[NEEDS-TRIAGE]`.
The status column is the pipeline's resume ledger: `subagent-driven-development` flips a task to
`ACCEPTED` the moment it accepts it, so an interrupted run (crash, compaction, closed session) is
re-entered by `/feature` at the first non-`ACCEPTED` task instead of restarted from brainstorming.
Gate: bijective coverage proven — no criterion without a task, no task without a criterion — and the
plan written to disk. This clears the path to execution: `executing-plans` (checkpointed, via
`/feature`) or `subagent-driven-development` (autonomous, via `/sprint`) — each routes every task
through `tdd`. The plan never hands off to `tdd` directly.
### Phase 4-farm extension (only when `--farm` was requested)
When `--farm` was requested, after the bijective coverage gate passes and the `.md` plan is written,
produce the farm artifact (`plan.json`) — **one MVP slice at a time** — per
`${CLAUDE_PLUGIN_ROOT}/routines/writing-plans/references/farm-plan.md`. Load that leaf and follow it;
it owns the per-task failing-test + schema-valid `plan.json` procedure.
Gate: all failing tests written and confirmed failing; `plan.json` written and schema-valid. Both
artifacts exist before handing off to `subagent-driven-development`.
## Hard rules
- MUST NOT plan against an absent or unapproved spec — STOP and route back to `/feature`.
- MUST NOT emit a task without an exact path AND a concrete verification step.
- MUST NOT let a task's verification stand in for a `tdd` gate — it maps to a tdd obligation, it does not replace one.
- MUST NOT write the plan while any acceptance criterion is uncovered or any task covers nothing.
- MUST NOT guess a verification command — cite `tech-stack.md` or STOP.
- MUST NOT resolve an ambiguous criterion by guessing — raise a `[CONFIRM-NN]`.
- MUST NOT emit `plan.json` in `--farm` mode without writing and confirming each failing test first.
- MUST NOT set `meta.model` or `meta.apiBaseUrl` in `plan.json` — these belong to the dispatch step.
- MUST NOT proceed with `--farm` if `FARM_API_KEY` is absent — cite `${CLAUDE_PLUGIN_ROOT}/includes/farm.md` and BLOCK.
- MUST, at exit, run the follow-up harvest (`${CLAUDE_PLUGIN_ROOT}/includes/harvest.md`) over any `[NEEDS-TRIAGE]` out-of-scope items — batch-confirm promoting them to `open-tasks.md` (work) or `open-questions.md` (decisions) so they don't die in the plan file.