Exec plan

ExecPlan — Lifecycle Management

Announce at start: "Using the exec-plan skill."

What is an ExecPlan

A self-contained, living document that a fresh agent session can follow to deliver observable, working behavior. Lives in docs/exec-plans/. The format follows the specification in docs/PLANS.md.

An ExecPlan is NOT a todo list. It is a narrative that tells the story of a change: why it matters, what the codebase looks like now, what it should look like after, and how to prove it worked.

When to use this skill

• Required for multi-step or multi-file work, new features, refactors, or tasks expected to take more than about an hour.
• Optional for trivial fixes, but if you skip it for a substantial task, state the reason.
• Always when resuming work from a previous session.

The Three Modes

Mode 1: CREATE a new plan

When starting new multi-step work:

1. Read docs/PLANS.md for the template and requirements.
2. Create the plan at docs/exec-plans/active/{descriptive-kebab-name}.md.
3. Fill ALL sections from the template. Non-negotiable sections:
   • Purpose / Big Picture — what the user can see/do after the change
   • Progress — empty checkboxes for each milestone
   • Surprises & Discoveries — start with (none yet)
   • Decision Log — start with (none yet)
   • Outcomes & Retrospective — start with (fill when complete)
   • Context and Orientation — full file paths, term definitions, current state
   • Plan of Work — narrative milestones with goal → work → result → proof
   • Concrete Steps — exact commands with expected outputs
   • Validation and Acceptance — observable proof of success
   • Idempotence and Recovery — how to retry or roll back
4. Every file path must be absolute from repo root.
5. Every term must be defined inline — assume the reader knows nothing.
6. Commit the plan before starting implementation.

Mode 2: CONTINUE an existing plan

When resuming work or executing the next milestone:

1. Read the plan file in docs/exec-plans/active/.
2. Find the first unchecked item in Progress.
3. Before starting work, check: are there any Surprises from previous sessions that affect this task?
4. Execute the milestone following the Plan of Work.
5. After each completed milestone, IMMEDIATELY update the plan:
   • Check the Progress item with a timestamp: - [x] (YYYY-MM-DD HH:MMZ) Description
   • Add any Surprises & Discoveries encountered
   • Add any Decision Log entries for choices made
6. Commit the plan update alongside the code changes.
7. Run the Validation commands to confirm success.

CRITICAL: Never claim a milestone is done without updating the plan file. The plan IS the persistence mechanism. If you don't update it, the next session will redo the work.

Mode 3: COMPLETE a plan

When all milestones are done:

1. Fill the Outcomes & Retrospective section:
   • What was achieved vs what was planned
   • Any remaining gaps
   • Lessons learned
   • Unexpected benefits or costs
2. Move the file: git mv docs/exec-plans/active/{name}.md docs/exec-plans/completed/{name}.md
3. Commit with message: docs: complete exec-plan {name}

Quality Checks

Before committing any plan (new or updated), verify:

• Purpose describes user-visible behavior, not just code changes
• Progress has timestamps on completed items
• Context names files by full path from repo root
• All terms are defined inline (no "see external doc" for critical terms)
• Validation has exact commands AND expected outputs
• Recovery section explains rollback for each risky step
• Surprises section is up to date (even if empty)
• Decision Log captures any choices made during implementation

Anti-patterns

• Checklist without narrative: "- [ ] Edit file X" tells the next session nothing. WHY edit it? WHAT changes? HOW to verify?
• External references for critical context: "See ARCHITECTURE.md for details" — the plan must be self-contained. Copy the relevant context in.
• Forgetting to update Progress: The most common failure. If you finish a milestone and don't check the box with a timestamp, the next session will redo it.
• Leaving completed plans in active/: After all milestones are done, MOVE to completed/. Active plans should only be unfinished work.
• Skipping Validation: "Tests pass" is not acceptance. "The isValid computed property no longer exists in the file, verified by grep -n isValid file.swift returning no results" IS acceptance.

Integration with other skills

• Before implementing plan milestones that involve TCA code: invoke /pfw-composable-architecture
• Before implementing plan milestones that involve debugging: invoke the debug skill
• Before implementing plan milestones that involve refactoring: invoke the refactor skill
• Before implementing plan milestones that involve API design: invoke the rest-api-design skill
• After completing all plan milestones: invoke refactor skill for a final cleanup pass