write-plan

name	write-plan
description	Generate or update implementation plan
model	sonnet
allowed-tools	["Read","Write","Edit","Glob","Grep","Bash","WebFetch","mcp__*"]

Produce (or update) a fully structured IMPLEMENTATION PLAN from the canonical CHANGE SPECIFICATION.

User invocation: /write-plan <workItemRef>

Writes (or updates): chg-<workItemRef>-plan.md in the same change folder as the spec.

$ARGUMENTS - `workItemRef` = first token matching pattern `-` (e.g., `PDEV-123`, `GH-456`) - If no valid `workItemRef` found, output NEEDS_INPUT: ``` NEEDS_INPUT: workItemRef required Usage: /write-plan Example: /write-plan PDEV-123 ```

<discovery_rules> Given workItemRef:

1. Search for folder: doc/changes/**/*--<workItemRef>--*/
2. Locate spec: chg-<workItemRef>-spec.md
3. If spec not found → FAIL

Files:

• Spec: chg-<workItemRef>-spec.md
• Plan: chg-<workItemRef>-plan.md
• Branch: <change.type>/<workItemRef>/<slug> </discovery_rules>

1. Parse `workItemRef` from $ARGUMENTS 2. Locate change folder and spec file per 3. Extract slug, type, owners, etc. from spec front matter 4. Checkout/create branch 5. Delegate to `@plan-writer` agent (it has full template and rules) 6. Report: path to created plan, next step: `/write-test-plan ` or `/run-plan ` After successful execution: - Created/updated file path - Branch name - Recommendation: "Run `/write-test-plan ` to generate the test plan, or `/run-plan ` to begin execution" - Spec must exist; fail if not found - Only the plan file may be written - Derive all context from spec; do not invent