| name | implement |
| description | Plan-then-implement workflow — sketches a hypothesis, explores targeted areas, creates a concrete plan, gets user approval, then implements in parallel subagents. Use for non-trivial features or changes. |
| allowed-tools | Agent Bash Read Grep Glob Edit Write TaskCreate TaskUpdate TaskList TaskGet |
Plan-Then-Implement Workflow
You are executing a structured implementation workflow for: $ARGUMENTS
Follow these phases strictly in order.
Phase 1: Sketch
Before exploring the codebase, form a rough hypothesis based on what you already know (skills, CLAUDE.md, conversation context, the request itself):
- What areas of the codebase likely need to change?
- What is the rough approach?
- What specific questions need answering before you can make a concrete plan?
Write this sketch down briefly. It does NOT need to be correct — its purpose is to give exploration direction, not to commit to an approach.
Phase 2: Explore
Use the Explore subagent (or multiple in parallel) to validate and refine the sketch. Focus exploration on:
- Answering the specific questions from the sketch
- Verifying that the files and patterns you hypothesized actually exist
- Discovering anything the sketch missed — dependencies, constraints, edge cases
- Checking existing patterns and conventions to follow
- Identifying test patterns used for similar features
Do NOT start writing code yet.
Phase 3: Plan
Enter plan mode. Based on what exploration confirmed or revised, create a concrete implementation plan:
- List every file that needs to be created or modified
- Describe the specific changes for each file
- Identify which changes are independent (can be parallelized) vs sequential
- Note any risks or decisions that need user input
- Include a test plan
Present the plan to the user and wait for approval before proceeding. Do not continue until the user confirms.
Phase 4: Implement
After user approval:
- Create tasks for each piece of work
- Exit plan mode
- Launch implementation subagents in parallel for independent work items (use
isolation: worktree for parallel file edits to the same files)
- Handle sequential work items in order after parallel work completes
- Mark tasks as completed as each finishes
Phase 5: Verify
After all implementation is done:
- Run the linter:
pixi run pre-commit run -a
- Run relevant tests:
pixi run python -m pytest tests -m "unit or integration" (adjust markers based on what was changed)
- Fix any issues found
- Summarize what was done
