Histogram Bug Discovery Guidelines

Use these instructions to find existing "Check expiry" bugs for histograms, or to create a new tracking bug.

The Discovery Query

CRITICAL MANDATE: You MUST use the mcp_Coding_internal_search tool (Moma) for ALL discovery and verification. NEVER use mcp_Buganizer_get_bugs or get_bugs for this process, as they redact Chromium issues and return unrelated internal bugs.

Use this exact pattern in Moma: "Check expiry of your histograms" "<HistogramName>" "<ExpiryDate>" status:open

• <HistogramName>: The full name of the metric.
• <ExpiryDate>: The expires_after date from the XML (e.g., 2021-10-25).

Triage Rules (Oldest-ID-Wins)

Automated sweeps often create new bugs when old ones are ignored. However, the oldest bug is frequently the one that remains open while newer duplicates are closed.

1. Extract IDs based on the Moma URL: Look at the URL: provided in each Moma result to definitively determine the bug ID.
   • Buganizer URLs (b.corp.google.com/issues/<ID> or issuetracker.google.com/issues/<ID>): The <ID> is already a Buganizer ID. Use it directly.
   • Monorail URLs (bugs.chromium.org/p/chromium/issues/detail?id=<ID>): Use curl -sL to fetch this exact URL and extract the official migrated Buganizer ID from the redirect script (e.g., curl -sL "https://bugs.chromium.org/p/chromium/issues/detail?id=<ID>" | grep -o 'issues\.chromium\.org/[0-9]*'). Use the extracted ID.
2. Prioritize the lowest Buganizer ID: After extracting or resolving the Buganizer IDs from all the Moma links, compare them and use the lowest numeric ID in the Bug: footer to ensure you link to the oldest tracker.
3. Verify Status: Only use the ID if the Moma snippet suggests it is status:open or actively tracking expiry. Do not use Buganizer tools (render_issue, etc.) to verify the bug, as they will fail on restricted Chromium issues. Rely entirely on the information from Moma and the curl redirect.

Manual Triage (Fallback)

If no open bug is found, or if the Moma results only show closed/won't fix bugs, use ask_user (type='choice') to determine bug handling:

• label: "Generate New Bug", description: "Auto-create a Buganizer issue in the CodeHealth component"
• label: "Provide Existing Bug", description: "User will provide the existing Bug ID"
• label: "Skip Bug", description: "Do not include a Bug reference in the footer"

Execution

• Generate New Bug: Use run_shell_command (whoami) for LDAP. Use mcp_Buganizer_create_buganizer_issue (Component: 1456931, Hotlist: 8218789, Assignee: <LDAP>). Title: [histogram-cleanup] Remove expired histogram: <HistogramName>. Description MUST start with: "Note: This bug was automatically generated by the Chrome Code Health AI." followed by a statement that the histogram is being removed as it has expired and has no recording sites.
• Provide Existing Bug: Use ask_user (type='text') with question: "What is the Buganizer ID?".
• Skip Bug: Proceed without a Bug ID (use "none").