[BUG] Explore agent regression: repo scans 50x slower in 2.1.30/2.1.31

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Environments

• OS's affected:

Fedora 6.18.7-200.fc43.x86_64
Ubuntu 6.14.0-37-generic
Kali 6.16.8+kali-amd64
Windows 11 24H2 (build 26200), update revision 7623

• Claude Code: 2.1.31 (also affects 2.1.30)
• Working version: 2.1.29

Description

Explore agent hangs for 20+ minutes when scanning repositories. The same operation completes in under 60 seconds on 2.1.29.

Observed behavior

• 2.1.31: 27 minutes to scan repo
• 2.1.29: 34 seconds for the same repo

Workaround

Downgrade to 2.1.29 and disable auto-update:
npm install -g @anthropic-ai/claude-code@2.1.29

Add to ~/.claude/settings.json:
{"autoUpdaterStatus": "disabled"}

What Should Happen?

Expected behavior

Repo exploration should complete in under 60 seconds as it did in 2.1.29.

Error Messages/Logs

Steps to Reproduce

Reproduction

1. Install 2.1.31
2. Open any repository
3. Ask Claude to explore/scan the repo (e.g., "take a peek at my repo")
4. Observe the Explore subagent spawning 26+ tool uses and hanging

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.29

Claude Code Version

2.1.31 (Claude Code)

Platform

Anthropic API

Operating System

Other Linux

Terminal/Shell

Other

Additional Information

Regression introduced between 2.1.29 and 2.1.30. Affects all tested operating systems. The Explore subagent appears to make excessive API round-trips (26+ tool uses visible in UI) where previously it completed quickly. Repo size does not matter - even small repos hang for 20+ minutes.