Add public artifact reader support

engine.go

@@ -26,15 +26,17 @@ import (
 var ErrInvalidConfig = errors.New("invalid engine configuration")
 
 var (
-	ErrInvalidRequest  = errors.New("invalid run request")
-	ErrPromptNotFound  = errors.New("prompt not found")
-	ErrProfileNotFound = errors.New("profile not found")
-	ErrPromptLoad      = errors.New("failed to load prompt definition")
-	ErrProfileLoad     = errors.New("failed to load execution profile")
-	ErrArtifactLoad    = errors.New("failed to load artifact")
-	ErrPromptRender    = errors.New("failed to render prompt")
-	ErrLLMGenerate     = errors.New("failed to generate output")
-	ErrValidation      = errors.New("failed to validate output")
+	ErrInvalidRequest   = errors.New("invalid run request")
+	ErrPromptNotFound   = errors.New("prompt not found")
+	ErrProfileNotFound  = errors.New("profile not found")
+	ErrProfileRequired  = errors.New("profile selection is required")
+	ErrPromptLoad       = errors.New("failed to load prompt definition")
+	ErrProfileLoad      = errors.New("failed to load execution profile")
+	ErrAPIKeyEnvMissing = errors.New("api_key_env points to an unset environment variable")
+	ErrArtifactLoad     = errors.New("failed to load artifact")
+	ErrPromptRender     = errors.New("failed to render prompt")
+	ErrLLMGenerate      = errors.New("failed to generate output")
+	ErrValidation       = errors.New("failed to validate output")
 )
 
 // Engine prepares and runs Scriptorium prompt requests.
@@ -68,6 +70,7 @@ func (f optionFunc) apply(options *engineOptions) error {
 
 type engineOptions struct {
 	llmClient       llm.Client
+	artifactReader  artifactadapter.Reader
 	promptDefs      promptdef.Repository
 	profiles        profile.Repository
 	memoryProfiles  profile.Repository
@@ -76,6 +79,7 @@ type engineOptions struct {
 	profileSource   bool
 	memorySource    bool
 	validatorSource bool
+	artifactSource  bool
 }
 
 // WithLLMClient injects a custom LLM client for execution.
@@ -89,6 +93,18 @@ func WithLLMClient(client LLMClient) Option {
 	})
 }
 
+// WithArtifactReader injects a reader for every input artifact reference.
+func WithArtifactReader(reader ArtifactReader) Option {
+	return optionFunc(func(options *engineOptions) error {
+		if reader == nil {
+			return ErrInvalidConfig
+		}
+		options.artifactReader = publicArtifactReaderAdapter{reader: reader}
+		options.artifactSource = true
+		return nil
+	})
+}
+
 // WithPromptFS loads prompt definitions from fsys under root.
 //
 // The source uses the same strict prompt YAML rules as configured prompt
@@ -253,11 +269,16 @@ func NewEngine(cfg Config, opts ...Option) (*Engine, error) {
 		}
 	}
 
+	artifacts := options.artifactReader
+	if !options.artifactSource {
+		artifacts = artifactadapter.NewCompositeReader()
+	}
+
 	return &Engine{
 		runner: usecase.NewRunner(
 			promptDefs,
 			profiles,
-			artifactadapter.NewCompositeReader(),
+			artifacts,
 			prompt.NewGoRenderer(),
 			llmClient,
 			validator,