Add automated triage bot for metadata-only issues

[twcclegg]

Changes

• Add .github/workflows/triage_metadata_issues.yml, which runs on every newly opened issue and uses the GitHub Copilot CLI (actions/ai-inference with the copilot provider) to classify whether it's actually a report about upstream Google libphonenumber metadata — an unrecognized prefix, an outdated numbering plan, a new country code — rather than a bug in this port's C# code.
• Looking through the issue history, this pattern shows up constantly (SA mobile numbers starting with 579 are rejected by IsValidNumber (IsPossibleNumber=true) #313, New phone number format for Benin not supported #272, New regulation for phone number prefixes in Australia #259, French mobile numbers with prefix "07" are not detected as mobile numbers #214, New Kazakhstan country code. #173, Outdated MetaData version #153, Required to update US phone number code 627 #143, Some phone calling codes may not be completely correct #118, Australian phone number beginning with 0480 not recognised as valid #112, Australian phone numbers starting with 048 not recognised as valid #104, ...) and maintainers have been closing these by hand for years with essentially the same reply pointing to google/libphonenumber. The classifier's prompt is grounded in that history (both the closed "yes, file it upstream" examples and the closed "no, this was actually a code bug" examples like Parsing phone number as valid when it starts with _ #183/Breaking change in PhoneNumberUtil.Normalize #206/Version 8.13.26 causes IndexOutOfRangeException #212).
• When the classifier is confident it's a metadata issue, the workflow labels it metadata (creating the label if needed), posts a canned comment explaining why and linking to the upstream repo + the bug_report.md checklist, and closes the issue (state_reason: not_planned). The comment explicitly says the flag was automatic and to reopen if it's a false positive.
• Skips issues opened by the maintainers themselves (OWNER/MEMBER/COLLABORATOR), and fails open: if the CLI errors or its response can't be parsed, or the confidence comes back low, the issue is left untouched for a human.
• Documented the new workflow in the README under a new "Automated triage of metadata issues" section.

Setup required after merge

This uses the modern (PAT-free) way of running Copilot CLI in Actions: permissions: copilot-requests: write plus the built-in GITHUB_TOKEN. That requires GitHub Copilot CLI usage to be enabled for the twcclegg account (the "Allow use of Copilot CLI" policy) — see https://docs.github.com/en/copilot/how-tos/copilot-cli/use-copilot-cli-in-actions. No repository secret needs to be created.

Test plan

• Validated the workflow YAML parses and the embedded github-script blocks are syntactically valid JavaScript.
• Confirmed actions/ai-inference pinned SHA corresponds to its v3 tag (the current Copilot-CLI-only major version — v1/v2 default to the now-retired GitHub Models API and would not work).
• Can't fully exercise the issues: opened trigger from a PR — once merged, open a throwaway test issue that mirrors e.g. SA mobile numbers starting with 579 are rejected by IsValidNumber (IsPossibleNumber=true) #313 ("SA mobile numbers rejected") to confirm it gets classified, labeled, commented, and closed automatically, and a normal bug/question issue to confirm it's left alone.

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Generated by Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.27%. Comparing base (e75ae83) to head (e6829c6).
⚠️ Report is 43 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #422      +/-   ##
==========================================
- Coverage   87.42%   87.27%   -0.15%     
==========================================
  Files          41       41              
  Lines        3856     3828      -28     
  Branches      990      978      -12     
==========================================
- Hits         3371     3341      -30     
  Misses        283      283              
- Partials      202      204       +2     

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[twcclegg]

Pushed a follow-up commit per feedback:

• Replaced the handful of hardcoded examples in the classifier's system prompt with two exhaustive, human-verified files: metadata_examples.md (30 confirmed "redirect to Google" issues) and not_metadata_examples.md (26 confirmed real bugs/questions/build issues), both compiled by reading through this repo's closed-issue comment history rather than guessing.
• The workflow now closes each list into the system prompt at runtime (cat into a temp file, fed via system-prompt-file).
• Added a step that, whenever the bot closes a new issue as a metadata issue, opens a PR appending that issue to metadata_examples.md — so the classifier's grounding keeps growing from real outcomes instead of staying frozen at this snapshot. That needed contents: write and pull-requests: write added to the workflow's permissions.

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Generated by Claude Code

[twcclegg]

Pushed another update per feedback:

• Dropped not_metadata_examples.md entirely.
• metadata_examples.md is now the single source of truth, framed explicitly: every issue Update README.md #1–Add automated triage bot for metadata-only issues #422 is either a PR (issues and PRs share one number sequence in this repo), a listed metadata issue, or — by not appearing in the list — an implied non-metadata issue. No third bucket.
• Went back through the rest of the closed-issue history to make the list genuinely exhaustive rather than a curated sample — caught several I'd missed the first pass (Update To 7.7.4 #14, Personal numbering #25, Letters in number are not recognized and no exception is thrown. #109, Outdated Version. Next Update? #149, Country Code is added to NationalNumber in PhoneNumber Object if Number is too short #165, IsPossibleNumberForTypeWithReason returns valid mobile when IsValidNumber returns invalid #181, Vietnamese Phone Numbers Not Returning as Valid #91), each verified against its actual resolution comment. 30 → 39 entries.
• Updated system_prompt.md and the workflow's cat step to match (only two files get concatenated into the classifier prompt now).

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