Function Calling Error Handling — Robust Tool Recovery

I will implement comprehensive error handling for your LLM function calling system — covering typed error responses that enable the LLM to reason about failures, retry logic with exponential backoff for transient failures, alternative function suggestion when the primary function fails, graceful degradation when no functions are available, and user-facing error messaging that maintains conversational flow despite backend failures. Function calling systems without proper error handling fail catastrophically on the first tool execution failure — the LLM receives an error response it wasn't designed to handle, and either loops trying the same failing call, abandons the task entirely, or produces a confusing response that exposes the technical failure to the user.

The implementation covers typed error response schema for function failures, error classification (transient vs. permanent), retry logic with exponential backoff for transient failures, alternative function routing for permanent failures, graceful degradation messaging, and user-facing error communication that maintains helpful conversational flow.