fix: validate tool_result IDs after condensation filtering (ROO-380)

[daniel-lxs]

Summary

Fixes vscode-lm provider 400 error where tool_result blocks reference condensed-away tool_use blocks.

Error:

"messages.0.content.0: unexpected `tool_use_id` found in `tool_result` blocks: toolu_vrtx_017zoz78rZkfhPsVf1SJkx1k. Each `tool_result` block must have a corresponding `tool_use` block in the previous message."

Root Cause

1. validateAndFixToolResultIds() runs when messages are added to history
2. Condensation happens later - tagging messages with condenseParent
3. getEffectiveApiHistory() filters out condensed messages
4. tool_results now reference non-existent tool_uses → 400 error

Solution

Add validation directly in getEffectiveApiHistory() after condensation filtering:

1. Find the last assistant message using findLast()
2. Get tool_use blocks from that assistant message
3. Get tool_results from the following user message
4. Validate that all tool_result IDs match valid tool_use IDs
5. If mismatches detected:
   • Report to telemetry with context
   • Fix IDs by position-based matching
   • Remove orphaned tool_results that can't be matched

Efficiency

• 8 early exit points for fast path when no issues
• Only processes last 2 messages, not entire history
• Uses Set for O(1) ID lookups
• Only creates new arrays when mismatches detected

Test Coverage

• 18 new tests covering all scenarios
• Tests include exact bug scenario simulation with condensation
• All existing condense tests (83) and task tests (124) pass

Linear Issue

Closes ROO-380

---

Important

Adds validation in getEffectiveApiHistory() to ensure tool_result IDs match existing tool_use IDs after condensation filtering, fixing mismatches and removing orphans.

• Behavior:
  • Adds validation in getEffectiveApiHistory() to ensure tool_result IDs match existing tool_use IDs after condensation filtering.
  • Fixes mismatched IDs by position-based matching and removes orphaned tool_results.
  • Reports mismatches to telemetry.
• Efficiency:
  • Early exits for fast path when no issues.
  • Processes only the last 2 messages.
  • Uses Set for O(1) ID lookups.
• Test Coverage:
  • 18 new tests in getEffectiveApiHistory-tool-validation.spec.ts.
  • Tests cover scenarios including condensation and ID mismatches.
• Misc:
  • Uses findLast() from array module in index.ts.

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[roomote]

Rooviewer   See task on Roo Cloud

Review complete. No issues found.

The implementation correctly addresses the vscode-lm provider 400 error by validating tool_result IDs after condensation filtering. The code is well-structured with 8 early exit points for performance, comprehensive error handling, and thorough test coverage (18 new tests, all passing).

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