Plan Feature

Turn a design into a short execution plan before editing code. For a new change, brainstorm-feature writes design.md and calls this skill before any approval; the user then approves design.md and tasks.md together, once. "The design" means that written design.md. Save tasks.md beside it in the change folder (using-devkit's ## Change lifecycle). A legacy design with no change folder is covered by ../using-devkit/references/legacy.md; read it when you meet one. Create the folder only when writing the plan.

Entry points

• Route handoff from brainstorm-feature: write the plan and present it for the joint approval (step 9).
• Route handoff from estimate-feature: when the user asked for an estimate and only a written design.md exists, write the plan, call estimate-feature before the approval gate, and present the plan and estimate together.
• Route handoff from implement-task: a material decision found during implementation. Revise the open tasks.md, record the decision in its ## Decision Log, reset the gate to pending, present the revision for approval, and resume implement-task after re-approval.
• Repair handoff (e.g. estimate-feature asking for missing task detail in an existing plan): fix the plan, run the self-review, and return to the caller with the gate preserved or reset and the reason. Do not call estimate-feature or ask for approval, and never start implementation.

Process

1. Read the design, AGENTS.md, and related wiki pages. If application source exists, call the available Skill entry whose local name is read-codebase-context to inspect affected source, callers, and tests; otherwise map planned files and interfaces from the design and state that callers and tests do not exist yet. Revise an open change's tasks.md in place; new architectural work after a change is archived gets a new design and folder. Keep completed tasks and results historical; add new work as a new task only while the change is open. Extract only exact constraints from the design that bind more than one task; infer none from convention.
2. Map which files will be created or modified and what each is responsible for. Follow existing patterns; do not unilaterally restructure. Before accepting a proposed unit, apply implement-task's ## Implementation ladder, planning new code only at its last step. Every new file, abstraction, dependency, or configuration value must map to an approved requirement, and minimal design must not remove explicit behavior, trust-boundary validation, security, accessibility, or error handling that prevents data loss.
3. Split the work into small, ordered tasks with the fields in references/tasks-template.md (read it now). Put contract and data changes before their callers and tests beside the behavior they verify. Map every approved edge case to a task and a specific check. If planning exposes an unresolved case that would change observable behavior, scope, an interface, a schema, or a protected boundary, stop and call brainstorm-feature; leave only behavior-equivalent details for implement-task rulings. Add no tasks for speculative abstractions, and do not add review-and-verify or commit steps; implement-task owns the final review. Plans describe intended behavior and interfaces, not code: include no function bodies or full test code. Include exact snippets only when the precise string, regex, config value, or contract shape is itself a requirement.
4. Give each task a meaningful Verify check using the existing test runner and a failing test when it protects changed behavior. With no tests, use a repeatable check available in the project; do not add a test runner solely for the plan. Record the expected result, and mark a behavior cannot verify when no check can establish it. For a source-less project, the first task bootstraps the runtime and first entry point the design specifies, with its verification; if the design does not establish them, call brainstorm-feature.
5. Add ## Approval Gate and ## Decision Log as the template shows. A new tasks.md is Status: pending; revisions follow the template's revision rule.
6. Save the complete plan with ## Design, ## Global Constraints, and ## Impact map (seven fields from read-codebase-context's ## Trace and record the impact). The folder is indexed only on approval (step 9).
7. Run the self-review below and fix issues inline.
8. Do not estimate effort here. When the user explicitly requests an estimate, call estimate-feature before presenting the approval gate; otherwise present none. An estimate never authorizes implementation.
9. Before requesting approval or delivering a planning-only result, give a short summary in the user's language with links to the written files: Goal; Scope and impact; Tasks (count and ordered titles); Verification (checks, naming any limit); Documentation (pages to update, or wiki not applicable); Risks and decisions. Summarize the actual design and tasks, not a second plan. State whether approval authorizes implementation or the request stops at planning. Unresolved material decisions return to brainstorm-feature; never present the plan as ready to implement. Apply the template's revision rule first: an existing plan that stays approved is summarized without a new approval request. Otherwise present design.md, tasks.md, any delta.md, and the requested estimate together and ask for one approval, then stop without editing application code. Revise the files in place until the user explicitly approves; then set Status: approved, index the folder per using-devkit's ## Change lifecycle, and continue: call setup-codebase first when the target has no AGENTS.md or application source, then implement-task. That approval is the gate, so do not ask again. If the user limited the request to design or planning, record the approval and stop. End with the Next: block from using-devkit; for a pending gate it names the exact approval the user must give.

No placeholders

Every step must contain the actual content an engineer needs. Never write: "TBD", "TODO", "implement later"; "add appropriate error handling" without saying what; tests described as code rather than named cases with input → expected result; "similar to Task N" (repeat the details); steps that omit the specific behavior, interface, or check; references to types or functions defined in no task.

Self-review

Fix only issues that could change approved behavior, scope, plan correctness, or execution; skip wording preferences. Check: spec coverage (a task per design requirement); placeholders (none, per the section above); type consistency across tasks; links (design and index resolve; the design links only wiki pages read as context); gate (new tasks are Progress: todo with Result: none, existing tasks keep theirs, a new tasks.md has only Status: pending); minimal design (anything removable via the ladder); decision consistency (persisted decisions agree with tasks and approval; material changes leave the gate pending); global constraints (each copied from the design and consistent with every task, or None.); edge cases (each mapped to a task and check, with unresolved behavior routed to brainstorm-feature).

Prefer the fewest tasks that make the sequence and verification unambiguous.

Red flags