API Error 400: tool_use ids must be unique in version 2.1.19

Description

Claude Code version 2.1.19 fails with API error 400 when attempting any tool use. The error message indicates duplicate tool_use IDs are being generated.

Error Message

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.1.content.1: `tool_use` ids must be unique"},"request_id":"req_..."}

Steps to Reproduce

1. Install Claude Code 2.1.19 (current latest)
2. Run any command that triggers tool use:

``bash
claude --print "List files in the current directory"
``

1. Error occurs immediately when Claude tries to use tools (Bash, Read, Glob, etc.)

Environment

• Claude Code Version: 2.1.19
• Platform: macOS (Darwin 25.2.0)
• Installation Method: npm global install + auto-update in ~/.local/share/claude/versions/

Debug Log

From ~/.claude/debug/latest:

[DEBUG] Stream started - received first chunk
[DEBUG] executePreToolHooks called for tool: Bash
...
[ERROR] Error in non-streaming fallback: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.1.content.1: `tool_use` ids must be unique"},"request_id":"req_..."}

Workaround

Downgrading to version 2.1.17 resolves the issue:

rm ~/.local/bin/claude
ln -s ~/.local/share/claude/versions/2.1.17 ~/.local/bin/claude

Additional Context

• Simple prompts without tool use work fine (e.g., claude --print "Say hello")
• Issue persists even with:
• Fresh ~/.claude directory (completely removed and recreated)
• All plugins disabled
• Different working directories
• Version 2.1.17 works correctly with identical configuration
• The error appears to be in the "non-streaming fallback" code path based on debug logs