Add immutable namespace views

internal/domain/resource_identity.go

@@ -43,6 +43,12 @@ func resourceNamespaceFromID(id string) (string, bool) {
 // valid namespace/local-ID pair.
 func IsValidResourceID(id string) bool { return validResourceID(id) }
 
+// QualifyResourceID validates id and applies namespace to an unqualified ID.
+// An already-qualified ID is returned unchanged.
+func QualifyResourceID(id, namespace string) (string, bool) {
+	return qualifyResourceID(id, namespace)
+}
+
 // IsValidResourceNamespace reports whether namespace is nonblank and contains
 // no namespace separator.
 func IsValidResourceNamespace(namespace string) bool { return validResourceNamespace(namespace) }

internal/engine/engine.go

@@ -84,6 +84,13 @@ type Engine struct {
 	smokeTester *usecase.SmokeTester
 	inspection  configuration.Inspection
 	listing     identityInventory
+	namespaces  resourceNamespaces
+}
+
+type resourceNamespaces struct {
+	prompt  string
+	profile string
+	backend string
 }
 
 type identityInventory interface {
@@ -145,6 +152,14 @@ func New(cfg Config, options Options) (*Engine, error) {
 	}, nil
 }
 
+// WithNamespaces returns an immutable view sharing this engine's assembled
+// collaborators and configuration snapshot.
+func (e *Engine) WithNamespaces(prompt, profile, backend string) *Engine {
+	view := *e
+	view.namespaces = resourceNamespaces{prompt: prompt, profile: profile, backend: backend}
+	return &view
+}
+
 // InspectConfiguration returns read-only operations over the captured result.
 func (e *Engine) InspectConfiguration() configuration.Inspection {
 	if e == nil {
@@ -203,14 +218,43 @@ func (e *Engine) ListPrompts(ctx context.Context) ([]domain.PromptIdentity, erro
 	return e.listing.ListPrompts(ctx)
 }
 func (e *Engine) Prepare(ctx context.Context, request domain.RunRequest) (*domain.PreparedRun, error) {
+	request, err := e.qualifyRunRequest(request)
+	if err != nil {
+		return nil, err
+	}
 	return e.runner.Prepare(ctx, request)
 }
 func (e *Engine) PrepareExecution(ctx context.Context, request domain.RunRequest) (*usecase.PreparedExecution, error) {
+	request, err := e.qualifyRunRequest(request)
+	if err != nil {
+		return nil, err
+	}
 	return e.runner.PrepareExecution(ctx, request)
 }
 func (e *Engine) Run(ctx context.Context, request domain.RunRequest) (*domain.RunResult, error) {
+	request, err := e.qualifyRunRequest(request)
+	if err != nil {
+		return nil, err
+	}
 	return e.runner.Run(ctx, request)
 }
+
+func (e *Engine) qualifyRunRequest(request domain.RunRequest) (domain.RunRequest, error) {
+	var ok bool
+	if request.PromptID != "" {
+		request.PromptID, ok = domain.QualifyResourceID(request.PromptID, e.namespaces.prompt)
+		if !ok {
+			return domain.RunRequest{}, fmt.Errorf("%w: invalid prompt ID", usecase.ErrInvalidRequest)
+		}
+	}
+	if request.ProfileID != "" {
+		request.ProfileID, ok = domain.QualifyResourceID(request.ProfileID, e.namespaces.profile)
+		if !ok {
+			return domain.RunRequest{}, fmt.Errorf("%w: invalid profile ID", usecase.ErrInvalidRequest)
+		}
+	}
+	return request, nil
+}
 func (e *Engine) RunPrepared(ctx context.Context, prepared *usecase.PreparedExecution) (*domain.RunResult, error) {
 	return e.runner.RunPrepared(ctx, prepared)
 }