[BUG] Slash commands with Skill() in allowed-tools trigger rate limit on minimal diffs (regression)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

What's Wrong?

Custom commands (.claude/commands/*.md) that use model: sonnet override in their frontmatter consistently hit API Error: Rate limit reached, even when usage is minimal and the actual diff is trivial (1 file, 1 line changed). The same operations work fine as normal messages in the conversation. This was working perfectly until recently — no changes were made to the commands or skills.

What Should Happen?

The command should execute normally without hitting rate limits, as it did before.

Steps to Reproduce

1. Create a command .claude/commands/commit.md with model: sonnet in the frontmatter
2. Stage a minimal change (1 file, 1 line)
3. Run /commit
4. Get API Error: Rate limit reached

Testing performed

| Test | Result |
|------|--------|
| model: sonnet in frontmatter | ❌ Rate limit error |
| model: haiku in frontmatter | ✅ Works |
| No model: (uses session model, Opus 4.6) | ✅ Works |

The Skill() reference in allowed-tools is NOT the problem — commands without model: sonnet but with Skill() work fine.

Usage is nowhere near limits — at the time of failure, session usage was at 12%, weekly "all models" at 15%, and weekly Sonnet at just 2%.

Claude Model

Other

Is this a regression?

Yes, this worked in a previous version

Claude Code Version

2.1.76

Platform

Other (Claude Team subscription)

Operating System

macOS

Terminal/Shell

Other (Ghostty)

Additional Information

• Subscription: Claude Team
• Session model: Opus 4.6
• model: sonnet in command frontmatter triggers the rate limit error, regardless of actual usage. Using model: haiku or no model: (inheriting session model Opus) works perfectly.