writing-plans

name	writing-plans
description	Use when you have a spec or requirements for a multi-step task, before touching code. In this repository, multi-subsystem or lane-scoped work must create the package brief first and keep the plan aligned with the bounded package contract.

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: .trellis/plans/YYYY-MM-DD-<feature-name>.md

Repo Override: Package-First Work

If the task touches multiple subsystem groups, uses lanes, or needs a tracked review handoff:

1. create the package brief first
2. align the plan to the brief's lane, topic, goal, and out-of-scope notes
3. use the package-first-sdk-delivery skill for execution and closeout

Use:

qiniu-ai package init --lane <lane> --topic <topic> --goal <goal> --phase <phase> --success "<criterion>"

Then write the promoted plan under .trellis/plans/ using the same topic slug.

Bite-Sized Task Granularity

Each step is one action (2-5 minutes):

• "Write the failing test" - step
• "Run it to make sure it fails" - step
• "Implement the minimal code to make the test pass" - step
• "Run the tests and make sure they pass" - step
• "Commit" - step

Plan Document Header

Every plan MUST start with this header:

# [Feature Name] Implementation Plan

> **For Claude:** REQUIRED SUB-SKILL: Use executing-plans to implement this plan task-by-task.

**Goal:** [One sentence describing what this builds]

**Architecture:** [2-3 sentences about approach]

**Tech Stack:** [Key technologies/libraries]

---

Task Structure

### Task N: [Component Name]

**Files:**
- Create: `exact/path/to/file.py`
- Modify: `exact/path/to/existing.py:123-145`
- Test: `tests/exact/path/to/test.py`

**Step 1: Write the failing test**

```python
def test_specific_behavior():
    result = function(input)
    assert result == expected

Step 2: Run test to verify it fails

Run: pytest tests/path/test.py::test_name -v Expected: FAIL with "function not defined"

Step 3: Write minimal implementation

def function(input):
    return expected

Step 4: Run test to verify it passes

Run: pytest tests/path/test.py::test_name -v Expected: PASS

Step 5: Commit

git add tests/path/test.py src/path/file.py
git commit -m "feat: add specific feature"

## Remember
- Exact file paths always
- Complete code in plan (not "add validation")
- Exact commands with expected output
- Reference relevant skills with @ syntax
- DRY, YAGNI, TDD, frequent commits

## Execution Handoff

After saving the plan:

**"Plan complete and saved to `.trellis/plans/<filename>.md`. Ready to execute?"**

**If yes:**
- For package-first work: use `package-first-sdk-delivery`
- **REQUIRED SUB-SKILL:** Use executing-plans to work through tasks in batches
- Alternative: Use subagent-driven-development for task-by-task execution with self-review
- Follow TDD for each task
- Commit after each task passes