pr-reviewer

name	pr-reviewer
description	Review a pull request and process review comments left by others
license	MIT
compatibility	opencode
metadata	{"audience":"developers"}

Skill: Pull Request Review and Comment Processing

Use this skill when asked to:

• Review a PR — read the diff, assess quality, post a structured review.
• Process review comments — fetch comments left by others, triage them, and act on them.

Required Input

Input	Required	Description
PR number	yes	The GitHub pull request number (e.g. 80)
Product improvement notes	no	Feature/improvement brief that motivated this PR
Implementation plan	no	Ordered task list describing what the PR is supposed to do

If the product improvement or implementation plan are not supplied, infer intent from the PR title, body, and diff — but note the gap when reporting findings.

---

Phase 1 — Gather Context

Run all reads in parallel where possible to minimise latency.

1a. Identify the repository

gh repo view --json nameWithOwner
# → { "nameWithOwner": "dynatrace-oss/dynatrace-snowflake-observability-agent" }

Store OWNER and REPO for all subsequent calls.

1b. Fetch PR metadata and diff

gh pr view <PR#> --json number,title,body,baseRefName,headRefName,state,author,labels,milestone

gh pr diff <PR#>

The diff is the primary artefact for a review. Read it fully before drawing any conclusions.

1c. Fetch all review threads (open and resolved)

Use the GitHub GraphQL API to get rich thread data including file paths, line numbers, diff hunks, and resolution status. Request enough nodes to cover all threads — increase the first: value if the PR is large.

gh api graphql -f query='
{
  repository(owner: "<OWNER>", name: "<REPO>") {
    pullRequest(number: <PR#>) {
      title
      body
      reviewThreads(first: 50) {
        nodes {
          id
          isResolved
          isOutdated
          path
          line
          originalLine
          diffHunk
          comments(first: 10) {
            nodes {
              databaseId
              author { login }
              body
              createdAt
              updatedAt
              minimizedReason
            }
          }
        }
      }
      reviews(first: 20) {
        nodes {
          author { login }
          state
          body
          submittedAt
        }
      }
    }
  }
}'

Pipe through python3 -m json.tool for readable output. Store the result — it is the source of truth for all comment-processing decisions.

1d. Read relevant source files for context

For every file mentioned in review threads or the diff, read the surrounding context using the Read tool (not cat). For large files, use offset + limit or the Grep tool to jump to the relevant region.

# Example: read lines 220-260 of a file referenced in a thread
# Use the Read tool with offset=220, limit=40

Do not guess at context. Read the actual file before forming an opinion.

---

Phase 2 — Analyse

2a. Classify each review thread

For every thread from the GraphQL result, assign:

Field	Values
Status	open / resolved / outdated
Severity	critical / important / minor / nit
Category	correctness / style / docs / tests / perf / security / architecture
Action	fix / address-in-comment / defer / disagree / already-done

Severity guide:

• critical — bug, data loss, security issue, broken contract, test that does not catch what it claims to catch.
• important — meaningful quality regression, misleading naming, incomplete coverage.
• minor — improvement that is clearly better but not blocking.
• nit — style, spelling, personal preference with no functional impact.

2b. Cross-reference against the implementation plan

If an implementation plan was provided, verify:

1. Every task in the plan has a corresponding change in the diff.
2. No task introduces unintended side effects visible in the diff.
3. Out-of-scope changes are flagged (scope creep).

2c. Run your own independent assessment

Beyond the existing comments, check for:

• Lint compliance (make lint, pylint 10.00/10, black, flake8, sqlfluff).
• Missing or incorrect tests (see docs/PLUGIN_DEVELOPMENT.md for the plugin test pattern).
• Missing docstrings (Google style, all public symbols).
• Missing BOM or instruments-def.yml updates for new plugins or metrics.
• Backward compatibility concerns (procedure signature changes need upgrade scripts, see copilot-instructions §Anti-Patterns).
• Copyright headers in new files.
• CHANGELOG.md / devlog file updates where required.

Before concluding that something is broken or missing, consult the actual source files. Do not flag issues based on the diff alone when the answer might be in an unchanged file.

---

Phase 3 — Prepare an Improvement Plan

Produce a structured plan in this format:

## PR #<N> — Improvement Plan

### Summary
<One paragraph: overall assessment, whether the PR is ready to merge, and the
main concerns.>

### Action Items

| # | Thread / Finding | File | Line | Severity | Category | Action | Notes |
|---|---|---|---|---|---|---|---|
| 1 | <thread id or "own"> | `path/to/file.py` | 123 | critical | correctness | fix | <what to do> |
| 2 | ... | | | | | | |

### Out-of-scope changes detected
<List any diff hunks that appear unrelated to the PR goal, or "None".>

### Deferred items
<Items that are valid but should be handled in a separate PR.>

Consult the human before acting on any item that would:

• Change public API or stored procedure signatures.
• Alter plugin behaviour or output schema.
• Modify configuration format or defaults.
• Touch files outside the PR's stated scope.

Present the plan to the human and wait for approval before moving to Phase 4.

---

Phase 4 — Implement Fixes

Work through the approved action items one at a time:

1. Mark the item in_progress in the TodoWrite tool.
2. Read the relevant file(s) with the Read tool.
3. Apply the change with the Edit tool.
4. Run make lint and .venv/bin/pytest after each change — do not batch.
5. Mark the item completed only after tests and lint are green.
6. Move to the next item.

Lint and test commands

make lint                                      # full lint suite
.venv/bin/pytest                               # full test suite
.venv/bin/pytest test/plugins/test_<X>.py -v  # single plugin

If a test fails, diagnose the root cause and fix it. Never "fix" a test by adjusting expected values to match wrong output — fix the code.

---

Phase 5 — Post Review (when acting as reviewer)

After completing all fixes, post a structured review using the GitHub CLI or the GitHub MCP tool.

Option A — CLI (prefer for full reviews)

# Approve
gh pr review <PR#> --approve --body "<review body>"

# Request changes
gh pr review <PR#> --request-changes --body "<review body>"

# Comment only
gh pr review <PR#> --comment --body "<review body>"

Option B — GitHub MCP (for inline comments on specific lines)

Use github_create_pull_request_review with comments array for line-level annotations. Each comment needs path, line, and body.

Review body template

## Review — PR #<N>: <title>

### Overall Assessment
<APPROVE / REQUEST_CHANGES / COMMENT> — <one sentence why>

### Critical Issues
<numbered list, or "None">

### Important Issues
<numbered list, or "None">

### Minor / Nit
<numbered list, or "None">

### Positive Observations
<what is done well — be specific>

---

Phase 6 — Respond to Others' Comments

When processing comments left by other reviewers (human or bot):

1. For every open thread: decide fix, address-in-comment, or defer.
2. For resolved threads: verify the fix is actually present in the diff — do not trust the resolved flag blindly.
3. For bot comments (e.g. copilot-pull-request-reviewer): evaluate on merit, not authority. Bots can be wrong.
4. Always reply to every thread you act on — whether you fixed, deferred, or disagreed. Use the first comment's databaseId from the GraphQL result:

# Reply to a specific review thread (requires the thread's first comment databaseId)
gh api repos/<OWNER>/<REPO>/pulls/<PR#>/comments/<comment-id>/replies \
  -f body="<your reply>"

Reply template:

• Fixed: "Fixed in commit <sha>. <one sentence describing what changed and why.>"
• Deferred: "Acknowledged. Deferred to a follow-up — <brief rationale>."
• Disagreed: "Disagree: <technical reasoning>. Leaving as-is."
• Already done: "This is already handled in <file>:<line> — <brief explanation>."

Run all replies in parallel (one gh api call per thread) — do not wait between replies.

---

Quick Reference — Common GraphQL Snippets

List unresolved threads only

gh api graphql -f query='
{
  repository(owner: "<OWNER>", name: "<REPO>") {
    pullRequest(number: <PR#>) {
      reviewThreads(first: 50) {
        nodes {
          isResolved
          path
          line
          comments(first: 5) {
            nodes { author { login } body }
          }
        }
      }
    }
  }
}' | python3 -c "
import json, sys
data = json.load(sys.stdin)
threads = data['data']['repository']['pullRequest']['reviewThreads']['nodes']
open_threads = [t for t in threads if not t['isResolved']]
print(f'{len(open_threads)} open thread(s)')
for t in open_threads:
    print(f\"  {t['path']}:{t['line']} — {t['comments']['nodes'][0]['body'][:80]}\")
"

Get PR files changed

gh pr view <PR#> --json files --jq '.files[].path'

Read a specific context window around a line in a file

Use the Read tool with offset and limit parameters — do not use sed -n or head/tail.

---

Pitfalls to Avoid

• Never resolve a thread without actually fixing the issue. Resolved status is set by the comment author, not by code presence — verify manually.
• Do not fabricate test data. If a test result file needs updating, re-run the test in live mode (-p flag) to regenerate fixtures from real output.
• Do not make unrelated changes. Note scope-creep findings in the plan and defer them.
• Do not post a review before the human approves the improvement plan.
• Do not change procedure signatures without an upgrade script. See copilot-instructions §Anti-Patterns.
• Always use .venv/bin/python / .venv/bin/pytest. Never system Python.