Function NewModelFactory

pkg/hooks/model_handler.go:119–149

NewModelFactory returns a [HandlerFactory] for [HookTypeModel] backed by client. Register it with [Registry.Register] in the runtime to enable `type: model` hooks. The returned factory pre-parses the prompt template at factory time so syntax errors surface at registry-lookup, not on the first hook

(client ModelClient)

// invocation. The shape/schema lookup happens at handler-construction
// time so adding new shapes after factory registration still works.
func NewModelFactory(client ModelClient) HandlerFactory {
	if client == nil {
		// The empty client always errors; this lets a runtime register
		// the factory without a credentialed client and fail at the
		// first use rather than at construction.
		client = nilClient{}
	}
	return func(_ HandlerEnv, hook Hook) (Handler, error) {
		if hook.Model == "" {
			return nil, errors.New("model hook requires a non-empty model")
		}
		if hook.Prompt == "" {
			return nil, errors.New("model hook requires a non-empty prompt")
		}
		shape, ok := lookupShape(hook.Schema)
		if !ok {
			return nil, fmt.Errorf("model hook: unknown schema %q (register one with hooks.RegisterResponseShape)", hook.Schema)
		}
		tpl, err := template.New("hook-prompt").Funcs(promptFuncs).Parse(hook.Prompt)
		if err != nil {
			return nil, fmt.Errorf("model hook: parse prompt template: %w", err)
		}
		return &modelHandler{
			client: client,
			model:  hook.Model,
			tpl:    tpl,
			schema: lookupSchema(hook.Schema),
			shape:  shape,
		}, nil
	}
}

// promptFuncs is the [text/template] FuncMap exposed to model-hook
// prompts. Kept small on purpose: anything more elaborate belongs in