write-executable-plan

Write Executable Plan

Bite-sized plans for parallel agents. No placeholders. No vague steps.

When to use

• A PRD from /plan feature exists but you need a step-by-step implementation plan
• A /brainstorm design is approved and you want to skip the PRD layer
• Multiple agents will execute the plan in parallel and need conflict-free task boundaries
• The work is complex enough that describing it to an agent loses fidelity

When NOT to use

• Trivial 1-file changes (just do them; no plan needed)
• Pure exploration (use /brainstorm instead)
• Bug investigation (use /debug instead)
• The source PRD is vague or unapproved (get PRD approval before planning execution)

Phase 0: Bootstrap Gate

Read skills/_shared/bootstrap-gate.md and execute the gate check. If the gate is CLOSED, invoke skills/bootstrap/SKILL.md and wait for completion before proceeding. If the gate is OPEN, continue to Phase 1.

<HARD-GATE> Do NOT proceed past Phase 0 if GATE_CLOSED. There is no bypass. Refer to skills/_shared/bootstrap-gate.md for the full HARD-GATE constraints. </HARD-GATE>

Phase 1: Source Selection

Accept ONE of the following inputs (in order of preference):

1. PRD path — docs/prd/YYYY-MM-DD-<feature>.md produced by /plan feature
2. Design spec path — docs/specs/YYYY-MM-DD-<slug>-design.md produced by /brainstorm
3. Inline description — user provides a free-text description; prompt for elaboration via AUQ before proceeding

If no source is provided and $ARGUMENTS is empty, ask via AUQ:

AskUserQuestion({
  questions: [{
    question: "Which source should this plan be based on?",
    header: "Plan Source",
    options: [
      { label: "Existing PRD (Recommended)", description: "Point me to docs/prd/YYYY-MM-DD-<feature>.md — most precise decomposition." },
      { label: "Design spec from /brainstorm", description: "Point me to docs/specs/YYYY-MM-DD-<slug>-design.md — skips formal PRD." },
      { label: "Describe inline", description: "Paste or describe the feature — I will ask follow-up questions before planning." }
    ],
    multiSelect: false
  }]
})

Read the source file and extract:

• Feature title (for filename slug and plan header)
• Acceptance criteria or equivalent (drives Task decomposition)
• Explicit out-of-scope items (excludes from plan)
• File inventory if present (seeds the whole-plan Files block)

Phase 2: Decomposition

Break the source into Tasks. Each Task MUST satisfy all of these constraints:

• Single owner — one agent role (e.g., code-implementer, test-writer), not "the team"
• Bounded file set — lists every file it creates, modifies, or tests; no file appears in two Tasks
• Independently testable — after Step 4 the task stands on its own; no cross-task dependencies in the test command
• 2-5 minute wall-clock estimate — if the estimate exceeds 5 minutes, split the Task; if two Tasks share a file, merge or re-scope

Before writing Tasks, output a brief decomposition plan in plain text:

## Decomposition (draft)
- Task 1: <title> — <owner> — ~<N> min — Files: <list>
- Task 2: <title> — <owner> — ~<N> min — Files: <list>
...

If any task's file set overlaps another, surface the conflict and resolve it before writing Steps.

Phase 3: Step Authoring (per Task)

Each Task gets exactly 5 steps in this order. All 5 steps are mandatory.

Step 1: Write the failing test

EARS seam: If the source PRD/spec carries an ## Acceptance Criteria (EARS) (or ## 3.A) section, apply the EARS→vitest 1:1 mapping below to emit per-clause test stubs. If no EARS section is present, fall back to manual derivation from prose.

EARS → vitest mapping (1:1)

| EARS pattern | vitest construct | example skeleton | |---|---|---| | Ubiquitous ("The S shall R.") | invariant it() — no setup branching | it('S shall R', () => { / assert invariant / }) | | State-driven ("While P, the S shall R.") | describe() for state context, nested it() for assertion | describe('while P', () => { it('S shall R', () => { / enter P; expect R / }) }) | | Event-driven ("When T, the S shall R.") | arrange/trigger/expect inside it() | it('when T, S shall R', () => { / arrange; trigger T; expect R / }) | | Optional feature ("Where F, the S shall R.") | it.skipIf(!F) (vitest conditional) | it.skipIf(!F)('where F, S shall R', () => { / expect R / }) | | Unwanted behaviour ("If C, then the S shall R.") | error-path it() with negative assertion or toThrow() | it('if C, then S shall R', () => { / induce C; expect R / }) |

Reference test exemplifying this pattern: tests/lib/wave-executor/persona-gate-hook.test.mjs (shipped at #481).

Follow .claude/rules/testing.md § "Test Quality — False-Positive Prevention": one meaningful assertion per it, behaviour not implementation, no branching, hardcoded expected values.

Provide:

• Exact file path (absolute from project root)
• Complete, runnable test code — no // ..., no placeholders, no // implement later
• One sentence explaining why this test verifies the intended behavior

The test MUST fail before Step 3 is applied. If the behavior already exists and cannot fail, pick a harder assertion or a new edge case.

Step 2: Run the test to confirm it fails

Provide:

• Exact command (e.g., npm test -- tests/unit/my-module.test.mjs)
• Expected terminal output — the specific assertion failure line that proves the test exercises missing code (not a generic "FAIL" — copy the actual error shape)

Step 3: Implement the minimal code

Provide:

• Exact file paths labeled Create: or Modify:
• Complete code — every function, every import, every export. No // add appropriate logic, no // similar to above, no ...
• DRY constraint: reuse existing utilities; do not duplicate logic that already exists in the codebase
• YAGNI constraint: implement exactly what makes Step 2's test pass; no speculative features

Step 4: Run the test to verify it passes

Provide:

• Same command as Step 2 (copy verbatim)
• Expected terminal output showing the test suite PASS line with the test name visible

Step 5: Commit

Provide:

• Exact commit message in Conventional Commits format: type(scope): subject
• Scope: the primary module or directory affected by this Task
• Subject: imperative mood, max 72 characters, no period
• Files staged: only this Task's files (list them)

Phase 4: Placeholder Linter

Before writing the plan to disk, scan every Step in every Task for forbidden strings. Any match is a rejection — fix before writing.

Forbidden strings (case-insensitive):

| Pattern | Why forbidden | |---------|---------------| | TBD, TODO, FIXME, XXX | Deferred decisions defeat the plan's purpose | | add appropriate error handling | Vague — specify the exact error type and handling code | | add error handling | Same — write the catch block | | similar to Task N, same as above, like Task N | Forces the executor to cross-reference; defeats file-disjoint execution | | etc. | Incomplete enumeration — list every item | | [fill in], <placeholder>, <YOUR_VALUE> | Template leftovers — fill them in | | ... inside a code block | Ellipsis in implementation code means incomplete code |

Prose ellipsis (e.g., "Phase 1... Phase 2...") is acceptable. Only code-block ellipsis is forbidden.

Any hit → surface to user via AUQ:

AskUserQuestion({
  questions: [{
    question: "The placeholder linter found forbidden strings in the draft plan:\n\n[list each hit with Task number, Step number, and matched text]\n\nHow do you want to proceed?",
    header: "Placeholder Linter",
    options: [
      { label: "Fix automatically (Recommended)", description: "I will resolve each hit by filling in the missing specifics before writing the plan." },
      { label: "Show me each hit interactively", description: "Walk me through each one so I can provide the missing detail." }