tree 5469d620466a368eae9f342bd240178e0e0cf57b
parent 15cc2e75ed6dc840c78bc7f2b2075d40d5f22470
author Josh Bleecher Snyder <josharian@gmail.com> 1748620403 +0000
committer Josh Bleecher Snyder <josharian@gmail.com> 1748633664 -0700

llm/conversation: fix duplicate tool results in insertMissingToolResults

Fix critical bug in insertMissingToolResults function that created duplicate
tool_result blocks when multiple tool uses were missing results, causing
Claude API 400 errors with message "each tool_use must have a single result".

Problem Analysis:
The function was designed to add error tool results for tool uses that
were requested but had no corresponding tool_result in the user message
(e.g., when hitting budget limits). However, when multiple tool uses
were missing results, the function incorrectly duplicated results:

1. First iteration: adds tool1 result to prefix, sets msg.Content = [tool1] + original
2. Second iteration: adds tool2 to prefix, sets msg.Content = [tool1, tool2] + [tool1] + original

This created duplicate tool_result blocks with the same tool_use_id, violating
Claude's API requirements and causing 400 Bad Request errors.

Root Cause:
The msg.Content assignment was inside the loop that builds the prefix:

Solution:
Move the msg.Content assignment outside the loop, after all missing
tool results have been collected:

Testing:
Added comprehensive test coverage for insertMissingToolResults with scenarios:
- Single missing tool result
- Multiple missing tool results (the problematic case)
- No missing results when results already present
- No tool uses in previous message

The test specifically verifies no duplicate tool_use_ids are created
and that all expected tool results are present exactly once.

This fix resolves the "multiple tool_result blocks with id" error
that was occurring in deep conversations with tool usage.

Fixes #121

Co-Authored-By: sketch <hello@sketch.dev>
Change-ID: s07f278af38b745aak