implement

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:

1. Create tasks for each piece of work
2. Exit plan mode
3. Launch implementation subagents in parallel for independent work items (use isolation: worktree for parallel file edits to the same files)
4. Handle sequential work items in order after parallel work completes
5. Mark tasks as completed as each finishes

Phase 5: Verify

After all implementation is done:

1. Run the linter: pixi run pre-commit run -a
2. Run relevant tests: pixi run python -m pytest tests -m "unit or integration" (adjust markers based on what was changed)
3. Fix any issues found
4. Summarize what was done