Dev pr description

PR Description Generator

Purpose

A good PR description answers three questions every reviewer has before they read a single line of code: What changed? Why does it exist? How do I verify it? This skill reads the diff and the story together to answer all three — so the reviewer spends their time reviewing, not detective-work.

---

Tool detection

1. Check for active mcp__azure-devops__* tools → $PM_TOOL = ado
2. Check for active mcp__jira__* tools → $PM_TOOL = jira
3. If neither → $PM_TOOL = manual

---

Step 1 — Read the git context

Run the following to understand what changed:

# Changed files and a summary of what moved
git diff --stat HEAD~1..HEAD 2>/dev/null || git diff --stat origin/main..HEAD

# Commit messages on this branch
git log --oneline origin/main..HEAD 2>/dev/null || git log --oneline -10

# Full diff (for understanding the nature of changes)
git diff origin/main..HEAD 2>/dev/null || git diff HEAD~1..HEAD

If git is not available or the branch has no commits yet, ask the developer to describe the changes.

---

Step 2 — Identify the linked story

Look for the work item ID in this order:

1. Branch name — extract a pattern like feature/#1234-, feat/PROJ-456-, dev/1234/, etc.
2. Commit messages — look for #1234, PROJ-456, Refs:, Closes:, or Fixes: references
3. Ask — "Which story does this PR implement? Provide the ID or paste the content."

Then fetch the story:

• ADO: use wit_get_work_item — read title, description, and acceptance criteria
• Jira: use the get-issue tool — read summary, description, and acceptance criteria
• Manual: accept pasted content

Store as $STORY.

---

Step 3 — Map changes to acceptance criteria

Before writing the description, build an internal map:

For each acceptance criterion in $STORY:

• Which files in the diff satisfy it?
• Is it fully satisfied, partially satisfied, or not covered?

Flag any AC that is not covered by the diff — this is either a missing implementation or the AC belongs to a different PR. Surface it: "AC [N] — '[text]' — does not appear to be covered by these changes. Is that intentional?"

---

Step 4 — Generate the PR description

Use this structure:

## What this does
[One sentence in user-facing language — what the user can now do that they could not before.
Not a technical summary. Not "refactored the service layer."]

## Work item
Closes #[ID]
[or: Refs: PROJ-456]

## Acceptance criteria covered
- [x] [AC text — copy verbatim from the story]
- [x] [AC text]
- [ ] [AC text — if intentionally deferred, explain why in a Note below]

## Changed files
| File | What changed and why |
|---|---|
| `path/to/file.ext` | [One line — what this file does differently and which AC it serves] |
| `path/to/test-file.ext` | [Tests for AC N and AC M] |

## How to test
1. [Step a reviewer can execute — environment, test data, or command]
2. [Expected result]
3. [Edge case or error state to verify]

## Notes
[Breaking changes, migrations needed, dependent PRs, feature flags, known gaps, or anything
the reviewer needs before they start. Leave blank if none.]

---

Step 5 — Review and finalise

Present the draft and ask: "Does this capture the PR accurately? Anything to add or adjust before I finalise it?"

Apply corrections. Once confirmed, output the final description in a clean code block ready to paste into GitHub, ADO, or Jira.

---

Guardrails

• Never describe changes in technical terms only — always include the user-facing outcome in the "What this does" section.
• Never mark an AC as covered if the diff does not contain changes that satisfy it.
• Never include secrets, tokens, connection strings, or personal data in the description — scan the diff for these before generating.
• If the diff is very large (more than 20 files), suggest splitting the PR: "This PR touches [N] files across [M] concerns. Consider splitting into smaller PRs — one per AC or one per layer — so reviewers can focus."
• Keep "How to test" steps executable by someone who did not write the code.