[BUG] Extremely slow performance / near-zero token generation since Feb 10, 2026

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?

Claude Code has been extremely slow since ~Feb 10, 2026. Simple prompts show
"Puzzling…" for 1m+ with minimal token usage (~3.7k tokens).

Already tried:

• Clearing conversation (/clear)
• Restarting Claude Code
• Reinstalling / updating to latest version
• Cleaning ~/.claude.json

The issue persists regardless of project or prompt complexity.

Environment

• OS: [your OS]
• Claude Code version: [run claude --version]
• Plan: [Pro/Max]
• Model: [Opus/Sonnet]

Expected Behavior

Normal response times (seconds, not minutes)

Additional Context

Coincides with Opus 4.6 Fast Mode errors reported on status.claude.com (Feb 10-11).

What Should Happen?

Claude Code should respond within seconds (5-15s) for standard prompts, generating tokens at a normal rate. Previously, the same tasks completed quickly with full token output. Expected normal performance without prolonged "Puzzling…" states or near-zero token throughput.

Error Messages/Logs

No explicit error messages. The issue manifests as:

- Status indicator shows: "Puzzling…" for 1m 10s+
- Token output: ↓ 3.7k tokens (minimal/near-zero generation)
- No timeout or crash — just extremely slow response

No error logs in terminal output.

Steps to Reproduce

1. Open Claude Code in terminal:

$ claude

1. Send any simple prompt, e.g.:

> "List the files in this directory"
or
> "Hello, how are you?"

1. Observe the status indicator shows "Puzzling…" and hangs for 60+ seconds

1. After response completes, note the minimal token usage (~3.7k tokens)

despite a trivial prompt

1. Repeat with different prompts — same behavior regardless of complexity

Note:

• Issue started ~Feb 10, 2026
• Not project-specific — occurs in any directory, even empty ones
• Persists after /clear, reinstall, and ~/.claude.json cleanup
• Issue coincides with reported Opus 4.6 Fast Mode degradation

on status.claude.com

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

48h

Claude Code Version

2.1.39

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_