stream-json mode: duplicate tool_use IDs error on multi-turn

Bug Description

When using -p --input-format stream-json --output-format stream-json mode, sending a second prompt after a tool use results in:

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

Reproduction

(echo '{"type":"user","message":{"role":"user","content":"run: echo hello"}}' && sleep 8 && echo '{"type":"user","message":{"role":"user","content":"keep going"}}') | claude -p --input-format stream-json --output-format stream-json --verbose --permission-mode bypassPermissions

Expected Behavior

Second prompt should work - conversation should continue normally.

Actual Behavior

First turn works (tool executes), second prompt fails with duplicate tool_use ID error.

Environment

• claude --version: 2.1.19
• macOS

Analysis

The error messages.1.content.1: tool_use ids must be unique indicates Claude CLI is building the messages array incorrectly when making the second API call. The tool_use ID from the first turn is being duplicated.