fix: prevent duplicate tool_use IDs causing API 400 errors

[daniel-lxs]

Summary

Fixes API 400 error "tool_use ids must be unique" occurring in v3.41.0 when using Anthropic Claude models with native tool calling.

Root Cause

NativeToolCallParser.rawChunkTracker is keyed by index (not by tool ID). When the same tool call ID arrives on multiple indices (e.g., during stream retry/reconnection):

1. Each index creates a separate tracker entry
2. Each tracker emits its own tool_call_start event
3. Multiple tool_use blocks with identical ID get added to assistantMessageContent
4. API sends these to Anthropic → 400 error

Solution

Two-layer defense against duplicate tool_use IDs:

Layer 1: Streaming Guard

Check streamingToolCallIndices.has(event.id) before adding new tool_use blocks during streaming to prevent duplicates from duplicate tool_call_start events.

Layer 2: Pre-flight Deduplication

Filter duplicate tool_use IDs before building the API request content as defense-in-depth.

Performance

Both layers add negligible overhead:

• Layer 1: O(1) hash lookup per tool_call_start
• Layer 2: O(n) where n = current response's tool calls only (typically 1-5)

Testing

• 10 new unit tests covering both deduplication layers
• All 5265 existing tests pass

Closes COM-494

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Important

Fixes API 400 errors by preventing duplicate tool_use IDs with two deduplication layers in Task.ts.

• Behavior:
  • Prevents duplicate tool_use IDs causing API 400 errors by implementing two deduplication layers in Task.ts.
  • Layer 1: Checks streamingToolCallIndices to avoid duplicate tool_call_start events during streaming.
  • Layer 2: Filters duplicate tool_use IDs before building API request content.
• Performance:
  • Layer 1: O(1) hash lookup per tool_call_start.
  • Layer 2: O(n) deduplication for current response's tool calls.
• Testing:
  • Adds 10 unit tests in duplicate-tool-use-ids.spec.ts covering both deduplication layers.
  • Ensures no duplicate tool_use blocks are added during stream retries or reconnections.

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[roomote]

Rooviewer   See task on Roo Cloud

Review complete. No issues found.

The two-layer defense against duplicate tool_use IDs is correctly implemented:

• Layer 1 guards during streaming via streamingToolCallIndices
• Layer 2 provides pre-flight deduplication when building API requests

Both layers properly sanitize IDs before comparison, state is correctly scoped and cleared between requests, and test coverage is comprehensive.

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