plan-feature

name	plan-feature
description	Plan a new feature before writing code. Explores the codebase, creates a structured plan with verification criteria, and only implements after approval.
disable-model-invocation	true
argument-hint	["feature description"]

Plan Feature

Create a structured implementation plan before writing any code. Based on the principle that planning before coding prevents wasted work and produces better results.

Usage

/plan-feature <description of the feature>

Procedure

Step 1: Understand the Request

Parse $ARGUMENTS to understand what feature the user wants. If the description is ambiguous, ask clarifying questions:

• What is the expected behavior?
• Are there any constraints (performance, compatibility, etc.)?
• Should this follow an existing pattern in the codebase?

Step 2: Explore the Codebase

Before planning, understand the existing architecture. Use the Explore agent or read files directly:

1. Find related code: Search for files related to the feature (e.g., if adding auth, search for existing auth/user code)
2. Understand patterns: How does the codebase structure similar features? (routing, services, models, tests)
3. Identify dependencies: What existing modules will this feature interact with?
4. Check for conventions: Read CLAUDE.md for project-specific conventions

Step 3: Create the Plan

Write a structured plan with these sections:

# Feature Plan: [Feature Name]

## Scope
What this feature does and does NOT do. Explicit boundaries.

## Affected Files
- `path/to/file1.ts` — What changes and why
- `path/to/file2.ts` — What changes and why
- `path/to/new-file.ts` — NEW: What this file does

## Approach
Step-by-step implementation order:
1. First, ... (because this establishes the foundation)
2. Then, ... (because this depends on step 1)
3. Finally, ... (integration and wiring)

## Risks & Edge Cases
- Risk: [description] → Mitigation: [approach]
- Edge case: [description] → Handling: [approach]

## Verification Criteria
How to confirm the feature works:
- [ ] Unit tests pass: `[specific test command]`
- [ ] Integration test: [describe manual or automated check]
- [ ] Edge case covered: [specific scenario]
- [ ] No regressions: `[full test suite command]`

Step 4: Save the Plan

Save the plan to a local file:

• Path: .claude/plans/<feature-slug>.md
• Create the .claude/plans/ directory if it doesn't exist

Step 5: Present for Approval

Show the plan to the user and ask for approval:

"Here's the implementation plan. Should I proceed, or would you like to adjust anything?"

Do NOT write any implementation code until the user approves the plan.

Step 6: Execute (After Approval)

Once approved:

1. Follow the plan step-by-step
2. After each step, verify it works before moving to the next
3. Run the verification criteria at the end
4. Report completion with a summary of what was done

If you discover the plan needs adjustment during implementation, stop and consult the user before deviating.