Tool hooks

The tool suite exposes a .hook() method that returns a builder with .before(), .after(), and .error() methods.

Use .filter(...names) to restrict which tools fire the hook:

const service = new OpenAIChatService();

// fires for ALL tools
service.tools().hook().before().do((name, args) => {
    console.log(`Running ${name}`);
    args.injected = "context";  // mutations affect the tool
});

// fires only for "greet"
service.tools().hook().filter("greet").after().do((result) => {
    console.log(`Done: ${result.result}`);
});

service.tools().hook().error().do((name, error) => console.error(`Failed: ${error.message}`));

Each returns a Hook — call .dispose() to unsubscribe. Async handlers in do() are awaited before tool execution proceeds (before-hooks) or before the next result is processed (after-hooks).

service.tools().clear() unregisters all tool event listeners alongside removing registered tools. Pass retainHooks: true to preserve listeners.

Before-hooks receive the actual args object — mutations in-place propagate to the tool. After- and error-hooks are observers (mutations don't affect the returned result).