Detecting Existing Threads

Purpose

Prevent duplicate comments by detecting existing review threads before posting new findings.

Required Tools

• Bash(gh pr view:*) - Get general PR comments
• Bash(gh api graphql -f query=:*) - Get resolved and open review threads (direct GraphQL)

Step 1: Determine PR Number

Use this priority order:

1. GitHub Actions environment:

   • Check GITHUB_EVENT_PATH environment variable
   • Extract PR number from event payload: .pull_request.number
   • Get repo from GITHUB_REPOSITORY ("owner/repo" format)

2. Conversation context:

   • Direct number: "123" → use 123
   • PR URL: extract from https://github.com/org/repo/pull/456
   • Text reference: "PR #789" → extract 789

3. Local review mode:

   • No PR number available → skip thread detection entirely

Step 2: Fetch Thread Data

Capture BOTH comment sources:

# General PR comments
gh pr view <PR_NUMBER> --json comments

# Inline review threads (resolved + open)
gh api graphql -f query='
query($owner: String!, $repo: String!, $pr: Int!) {
  repository(owner: $owner, name: $repo) {
    pullRequest(number: $pr) {
      reviewThreads(first: 100) {
        nodes {
          id
          isResolved
          isOutdated
          path
          line
          startLine
          diffSide
          comments(first: 10) {
            nodes {
              id
              body
              author { login }
              createdAt
            }
          }
        }
      }
    }
  }
}
' -f owner="<OWNER>" -f repo="<REPO>" -F pr="<PR_NUMBER>"

Step 3: Parse Into Structure

Build this JSON structure from merged results:

{
  "total_threads": 5,
  "threads": [
    {
      "location": "src/auth.ts:45",
      "severity": "CRITICAL",
      "issue_summary": "SQL injection risk in query builder",
      "resolved": false,
      "author": "claude",
      "path": "src/auth.ts",
      "line": 45
    }
  ]
}

Severity detection from emoji prefix:

• ❌ → CRITICAL
• ⚠️ → IMPORTANT
• ♻️ → DEBT
• 🎨 → SUGGESTED
• ❓ → QUESTION

Thread Matching Logic

Before creating any new comment, check for matches:

Match Type	Criteria	Action
Exact	Same file + same line	Use existing thread
Nearby	Same file + line within ±5	Use existing thread
Content	Body similarity >70%	Use existing thread
No match	None of above	Create new comment

Handling Matches

• Issue persists unchanged → Respond in existing thread
• Issue resolved → Note resolution, don't re-raise
• Issue evolved → Create new comment explaining change