writing-plans

Writing Plans

Overview

Write comprehensive implementation plans assuming the engineer has zero context for our codebase and questionable taste. Document everything they need to know: which files to touch for each task, code, testing, docs they might need to check, how to test it. Give them the whole plan as bite-sized tasks. DRY. YAGNI. TDD. Frequent commits.

Assume they are a skilled developer, but know almost nothing about our toolset or problem domain. Assume they don't know good test design very well.

Announce at start: "I'm using the Writing Plans skill to create the implementation plan."

Context: This should be run in a dedicated worktree (created by brainstorming skill).

Save plans to: docs/plans/YYYY-MM-DD-<feature-name>.md

Quick Reference

Plan header template: See Plan Structure & Templates

Task template: See Plan Structure & Templates

Granularity guide: Each step = 2-5 minutes. See Best Practices

Core Principles

• Exact file paths always - Not "in the user module" but "src/models/user.py"
• Complete code in plan - Not "add validation" but show the validation code
• Exact commands with expected output - "pytest tests/file.py -v" with what you'll see
• Reference relevant skills - Use @ syntax: @skills/category/skill-name
• DRY, YAGNI, TDD, frequent commits - Every task follows this pattern

For detailed guidance: Best Practices & Guidelines

Execution Handoff

After saving the plan, offer execution choice:

"Plan complete and saved to docs/plans/<filename>.md. Two execution options:

1. Subagent-Driven (this session) - I dispatch fresh subagent per task, review between tasks, fast iteration

2. Parallel Session (separate) - Open new session with executing-plans, batch execution with checkpoints

Which approach?"

If Subagent-Driven chosen:

• Use @skills/collaboration/subagent-driven-development
• Stay in this session
• Fresh subagent per task + code review

If Parallel Session chosen:

• Guide them to open new session in worktree
• New session uses @skills/collaboration/executing-plans

Remember

• Write for zero-context engineers (specify everything)
• Complete code blocks, not instructions
• Exact commands with expected output
• Test first, then implement, then commit
• Reference existing patterns in codebase
• Keep tasks bite-sized (2-5 minutes each)

Need examples? See Plan Structure & Templates for complete task examples.

Need patterns? See Best Practices for error handling, logging, test design, and more.