Structured Planning

The user's instructions take precedence over this skill; carry existing authorization forward and do not add approval gates. If the user requested only a plan, deliver the plan without starting implementation.

Size the Plan by Uncertainty

File count is a poor proxy for risk: a one-line authorization change can need more analysis than a mechanical rename across many files.

Establish the Actual Starting Point

Inspect repository status and relevant diffs, and locate the real verification commands in scripts, hooks, or CI. Record the facts that constrain execution:

• The observable user or system outcome.
• The baseline revision or environment inspected.
• The ship state (pre-launch, single consumer, or production with users), which decides how much migration machinery the plan may carry.
• Affected interfaces, ownership, and compatibility obligations.
• Uncertainty that could invalidate the work.
• Explicit constraints, non-goals, and user corrections, with requirements ("must") kept distinct from preferences stated casually.
• Constraints the user treats as obvious and left unsaid: a convention, a taste, an integration they assume. Where two readings produce materially different work, ask once with the pick stated; otherwise record the reading taken.

Treat an inherited plan as a hypothesis: recheck consequential claims against the current tree before executing them. When a premise fails, update the plan itself, because a detached comment leaves the executor on stale instructions.

Choose a Useful Slice

Prefer a vertical slice that carries a real input through the uncertain boundary to the consumer that needs it. Simplification must preserve the requested result: do not replace a difficult product goal with a convenient demonstration of plumbing. Sequence migrations by compatibility and deployment; source-file order does not determine safe rollout order.

Keep implementation and its behavioral verification in the same accountable task. A title containing "and" is not evidence that the task should split; split at independently reviewable outcomes, distinct owners, or real dependency boundaries.

Give Each Task an Executable Contract

Use only the fields the task needs:

### Task: Reject expired sessions at the request boundary

Outcome: An expired session receives the established unauthorized response.
Scope: The session validator and its request-level tests.
Depends on: The existing clock injection interface, confirmed in the repo.
Verify: [repository's exact focused test command].
Cases: Expired, valid, and boundary-time sessions preserve expected behavior.
Completion: Tests exercise the request path and report executed cases.

A copyable command still needs an assertion: "renders" does not prove that the generated policy matches the intended resources.

Map Dependencies and Ownership

File separation does not prove independence: two modules can share a schema, generated file, test database, port, or output directory. Name those shared resources and their owners. Designate an integration owner who verifies combined behavior after branches or patches meet.

Make the Plan Resumable

Select one authoritative plan and link it from the project's tracker rather than duplicating it across chat, repository files, and memory. Do not create or commit planning documents merely because work spans sessions. A plan is read by a human and a future session, not by the model that wrote it: keep it to the decisions, contracts, and open calls, and when the host renders rich artifacts, put each open question beside the diagram or snippet it concerns.

A checkpoint records the current revision, completed outcomes and evidence, active ownership, pending decisions, and the exact next step. On resumption, re-read the checkpoint and inspect live state; notes describe a past state.

Replan Without Losing the Goal

When implementation exposes a new constraint, carry the correction through tables and acceptance criteria, not just the edited paragraph. A case the plan did not cover gets its call recorded beside the task it affects, with the alternative rejected; a call that lives only in the code is lost at the next checkpoint. At integration boundaries, compare the accumulated diff with the intended outcome; tests can pass while scope drifts.

Report an unavailable external gate separately from completed local checks, with its blocker and next action.

Evidence

Reviewed 2026-09-04 and 2026-10-27; sources and their limits are in references/evidence.md.

Anti-Patterns

What This Skill is NOT

• A requirement for trivial work or a fixed file-count threshold.
• Permission to execute a plan-only request.
• A promise that an initial architecture, schedule, or task list cannot change.