Agent repeatedly searches GitHub (issues, PRs, gists) instead of grepping local repo

Bug

When asked to find information "on GitHub," the agent fixates on GitHub-hosted metadata (issues, PRs, wikis, gists, discussions) and ignores the local codebase — even when the user is clearly referring to a file committed to the repo.

Reproduction

1. Ask: "I'd like to hear more about my account info for polling accounts"
2. Agent queries Firestore (wrong source entirely)
3. Ask: "I wanted to know about my account info that's in GitHub"
4. Agent searches GitHub issues, PRs, gists, wiki, discussions — 5+ API calls, all misses
5. Ask: "I have a bunch of info about my resy account... name, phone number, etc."
6. Agent still searches GitHub issues
7. Ask: "Can you look for phone numbers somewhere?"
8. Only now does the agent grep the local repo — finds docs/accounts.md immediately

Expected behavior

When the user says their info is "on GitHub" (or "in the repo"), the agent should search the local codebase first (grep/glob), not GitHub's issue tracker. A simple grep for phone numbers or glob for **/accounts* would have found it in one shot.

Impact

Wasted ~6 turns and multiple minutes on a lookup that should have taken seconds. Erodes user trust.

Environment

• Claude Code CLI
• Model: claude-opus-4-6