When an LLM emits a truncated or malformed arguments field (e.g. "{") instead of valid JSON, downstream consumers such as LiteLLM reject the entire request with a 400 Bad Request, causing the chain to degrade into an infinite retry loop.
- SanitizeToolCallArguments now falls back to "{}" after control-char escaping if the result is still not valid JSON, fixing already-stored chains on restore
- callWithRetries logs a warning and substitutes "{}" at the moment the bad arguments arrive from the LLM, preventing them from ever reaching the database
- Added test cases for truncated JSON, partial objects, and empty strings
- Implemented `SanitizeJSONControlChars` to escape literal control characters in JSON string values, ensuring compliance with the JSON specification.
- Enhanced `SanitizeToolCallArguments` method to apply sanitization across tool call arguments in the chain.
- Added comprehensive tests for both sanitization functions to validate behavior with various input scenarios.
Dmitry Ng