PR Description Writer Skill

When to Use This Skill

Use this Skill when:

• Creating or updating a PR description for a feature branch.
• The PR has multiple related changes that need clear organization.
• You want a description that helps reviewers understand the "why" and "what" quickly while having access to detailed context.
• You're preparing a PR for review and want it to be self-documenting.

This Skill is designed to work with any repository but is especially tuned for Django/Python backends, React frontends, and infrastructure changes.

Example Prompts

• "Use pr-description-writer to create a PR description for my current branch."
• "Generate a comprehensive PR description for PR #1234 using the pr-description-writer Skill."
• "Update the PR description for my feature branch to match our standard format."

---

Workflow (High Level)

1. Gather PR and branch context (see references/gh-cli.md for exact commands).
2. Identify the base branch and enumerate all changes (committed + uncommitted).
3. Write a layered, reviewer-centric PR description using the structure below.
4. If the user wants, update/create the PR using gh (see references/gh-cli.md).

---

Core Principles

1. Scannable First, Detailed Second

Reviewers should understand the PR in 30 seconds from the summary, then dive deeper as needed. Structure content in layers:

1. Summary table – Quick overview of key features (30 seconds)
2. Visual diagrams – Understand flows without reading code (1-2 minutes)
3. Detailed sections – Full context for each feature (as needed)
4. Collapsible file lists – Reference without clutter

2. Visual Over Verbal

Use diagrams, tables, and structured formatting instead of prose where possible:

• Decision trees for conditional logic
• Flow diagrams for pipelines and processes
• Tables for feature summaries and comparisons
• Code blocks for commands and examples

3. Reviewer-Centric

Every section should answer a reviewer's question:

• "What does this PR do?" → Summary
• "Why was it done this way?" → Detailed sections with rationale
• "What files should I focus on?" → Collapsible file lists
• "How do I test this?" → Test commands + manual steps
• "Are there breaking changes?" → Explicit callouts

4. Complete Picture

Never describe only the latest commit. The PR description must reflect:

• All commits in the branch (from base to HEAD)
• Any uncommitted changes the user plans to include
• The cumulative effect of all changes together

---

PR Description Structure

Section 1: Summary

Start with a 1-2 sentence high-level summary, then provide a Key Features table if the PR has 3+ distinct features:

## Summary

This PR adds [brief description of the main change].

### Key Features

| Feature | Description |
|---------|-------------|
| **Feature A** | Short description of what it does |
| **Feature B** | Short description of what it does |
| **Feature C** | Short description of what it does |

For smaller PRs (1-2 features), a bullet list is acceptable.

Section 2: Visual Diagrams

For any non-trivial flow, include a visual diagram. Choose the appropriate format based on complexity:

ASCII Art (Simple Flows)

Use for decision trees and linear flows:

## Feature Flow

```
First condition?
     │
    YES ──► Has prior state? ──► YES: Action A
     │                       └──► NO:  Action B
     │
    NO ───► Action C
```

Mermaid (Complex Flows)

Use for multi-step pipelines, state machines, or architectures:

## Architecture

```mermaid
flowchart LR
    A[Step 1] --> B[Step 2]
    B --> C{Decision}
    C -->|Yes| D[Path A]
    C -->|No| E[Path B]
```

Box Diagrams (Pipelines)

Use for showing data flow or process stages:

## Data Pipeline

```
┌─────────────────┐     ┌─────────────────┐     ┌─────────────────┐
│   Input Stage   │────►│  Process Stage  │────►│  Output Stage   │
│  (description)  │     │  (description)  │     │  (description)  │
└─────────────────┘     └─────────────────┘     └─────────────────┘
```

Section 3: Detailed Feature Sections

For each major feature, provide a dedicated section with:

• What it does – Behavior description
• Why this approach – Rationale for key decisions
• Key implementation details – Important patterns or constraints

Use horizontal rules (---) to separate major features.

---

## Feature A: Title

Description of what this feature does and why.

Key implementation details:
- Point 1
- Point 2

---

## Feature B: Title

...

Section 4: Files Changed

Group files by category using collapsible sections:

## Files Changed

<details>
<summary>Core modules (click to expand)</summary>

- `path/to/file1.py` - Brief description
- `path/to/file2.py` - Brief description

</details>

<details>
<summary>Tests (click to expand)</summary>

- `tests/test_file1.py` - What it tests
- `tests/test_file2.py` - What it tests

</details>

Categories to consider:

• Core modules / Services
• API / Views / Routes
• Models / Migrations
• Tests
• Configuration / Settings
• Documentation

Section 5: How to Test

Provide both automated and manual testing instructions:

## How to Test

```bash
# Run all related tests
.bin/pytest path/to/tests/ -v
```

### Manual Testing

1. **Test scenario A**: Step-by-step instructions
2. **Test scenario B**: Step-by-step instructions

Section 6: Breaking Changes / Notes

Always include a section for special considerations:

## Notes

- **No Migrations**: This PR has no schema changes.

Or for PRs with important notes:

## Breaking Changes

- **API Change**: The `/api/endpoint` now returns X instead of Y.
- **Config Required**: Set `NEW_ENV_VAR` before deploying.

## Deploy Steps

1. Add environment variable `NEW_VAR=value`
2. Run migrations
3. Deploy code

---

When to Use Each Element

Scenario	Use
3+ distinct features	Summary table
Conditional logic	ASCII decision tree
Multi-step process	Box diagram or Mermaid
5+ files in a category	Collapsible details
Test commands exist	Code block with commands
Manual testing needed	Numbered step list
Schema changes	Explicit migration section
Breaking changes	Dedicated callout section

---

Common Patterns

Feature Flag Pattern

## Feature Flag

Controlled by `FEATURE_FLAG_NAME` (default: `False`).

When enabled:
- Behavior A
- Behavior B

When disabled:
- Falls back to original behavior

Migration Pattern

## Migrations

| Migration | Description | Reversible |
|-----------|-------------|------------|
| `0001_add_field.py` | Adds `new_field` to Model | Yes |
| `0002_backfill.py` | Backfills existing rows | Yes (data loss) |

### Rollback Plan

1. Revert code deployment
2. Run `./manage.py migrate app_name 0000_previous`

API Change Pattern

## API Changes

### New Endpoints

| Method | Path | Description |
|--------|------|-------------|
| `GET` | `/api/v2/resource` | Fetches resource with new format |

### Modified Endpoints

| Endpoint | Change |
|----------|--------|
| `GET /api/v1/old` | Now returns `new_field` in response |

### Deprecated

- `GET /api/v1/legacy` - Use `/api/v2/resource` instead

---

Anti-Patterns to Avoid

1. Wall of text – Use formatting (tables, lists, diagrams) instead of paragraphs.

2. Vague descriptions – "Various bug fixes" tells reviewers nothing. Be specific.

3. Missing test instructions – Always include how to verify the changes.

4. Buried breaking changes – Put them in a dedicated, visible section.

5. Listing every file – Use collapsible sections and group by purpose.

6. No visual aids for flows – If you need more than 2 sentences to explain a flow, use a diagram.

7. Describing only the latest commit – The PR description should cover ALL commits and changes in the branch.

---

References

• GitHub context-gathering commands (gh + git): references/gh-cli.md

Output

When this Skill generates a PR description, it should:

1. Gather all context first using the commands above.
2. Analyze ALL changes – not just the latest commit.
3. Output the full markdown for the PR description.
4. Offer to update the PR directly using gh pr edit if a PR exists, or create one using gh pr create if not.
5. Be ready to iterate based on user feedback.

The description should be copy-paste ready for GitHub.

Compatibility Notes

This Skill is designed to work with both Claude Code and OpenAI Codex.

• Claude Code: install the corresponding plugin and use its slash commands (see plugins/pr-description-writer/commands/).
• Codex: install the Skill directory and invoke name: pr-description-writer.

For installation, see this repo's README.md.