Type Alias ExternalToolHandlerFn 

pub type ExternalToolHandlerFn = Box<dyn Fn(String, Value) -> Pin<Box<dyn Future<Output = Option<ToolResult>> + Send>> + Send + Sync>;

Type alias for external tool handler callback.

When set, this handler is called before the built-in tool executor. If it returns Some(ToolResult), the built-in executor is skipped for that tool call. This allows embedding custom tools (e.g. MemorySearch, VaultGet) alongside the built-in tools (Read, Write, Bash, etc.).

Aliased Type

pub struct ExternalToolHandlerFn(/* private fields */);