fix: prevent invalid tool from leaking into model error messages

[nitishagar]

Issue for this PR

Closes #21900

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

When a model emits an invalid tool call, the AI SDK's NoSuchToolError includes the raw "Available tools: invalid, bash, read, ..." list. This gets passed through experimental_repairToolCall → the invalid tool → back into the model's context. The model sees "invalid" listed as a tool and may try calling it, entering a loop that the doom loop detector can't catch because each call has different input.

Three fixes:

1. llm.ts: Extract repairToolCall and build a clean error message that never leaks internal tool names or the "Available tools" list. Uses duck-typing on the error object to distinguish "tool not found" from "bad arguments."

2. processor.ts: Extend doom loop detection to circuit-break consecutive invalid tool calls regardless of input variation. The existing detector only catches identical calls (same name + same input).

3. invalid.ts: Strip any residual "Available tools: ..." text from the output as defense-in-depth.

How did you verify your code works?

• bun run typecheck passes
• All 30 existing + new tests pass (bun test test/session/llm.test.ts test/session/processor-effect.test.ts)
• 4 new unit tests for repairToolCall covering: case-insensitive repair, unknown tool clean error, invalid arguments error, exact match fallback

Screenshots / recordings

N/A - no UI changes

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Potential Related PRs Found:

1. PR fix(opencode): repair malformed JSON in tool call arguments #23067 - fix(opencode): repair malformed JSON in tool call arguments

   • fix(opencode): repair malformed JSON in tool call arguments #23067
   • Related because both address tool call repair mechanisms and error handling

2. PR feat: configurable tool alias map for repairing miscalled tools #14085 - feat: configurable tool alias map for repairing miscalled tools

   • feat: configurable tool alias map for repairing miscalled tools #14085
   • Related because it handles tool call repair and miscalled tools

3. PR fix(opencode): retry transient provider failures and tool-call diff/input errors #15850 - fix(opencode): retry transient provider failures and tool-call diff/input errors

   • fix(opencode): retry transient provider failures and tool-call diff/input errors #15850
   • Related because it addresses tool-call errors and input validation

These PRs all touch on tool call repair and error handling, though they may address different aspects. PR #23067 seems most directly related as it also deals with tool call argument repair. You may want to verify if these are solving overlapping issues or if they're complementary fixes.