diff --git a/docs/roadmap/implementation.md b/docs/roadmap/implementation.md
index be06894..e43e61f 100644
--- a/docs/roadmap/implementation.md
+++ b/docs/roadmap/implementation.md
@@ -123,6 +123,11 @@ Validation: format and run `go test ./examples/go-library/prepare`. Ensure
 imports and relative content still resolve from their contributing sources;
 do not rewrite configuration fixtures merely to bypass path handling.
 
+Completion: the preparation workflow accepts an explicit context, example
+directory, and writer while preserving its inline checks and source contexts.
+Its Go test verifies the retained summary, including explicit null collection
+metadata, and passed on Go 1.27.0.
+
 ## Stage 3: Test The Observation Example And Its Output
 
 Scope: `examples/go-library/observe/main.go` and its new `main_test.go`.
diff --git a/examples/go-library/prepare/main.go b/examples/go-library/prepare/main.go
index 51ec020..8410be3 100644
--- a/examples/go-library/prepare/main.go
+++ b/examples/go-library/prepare/main.go
@@ -4,7 +4,9 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"os"
+	"path/filepath"
 
 	"go.maximumdirect.net/configkit"
 	"go.maximumdirect.net/promptkit"
@@ -28,26 +30,33 @@ type collectionSummary struct {
 }
 
 func main() {
+	if err := run(context.Background(), "examples/go-library/prepare", os.Stdout); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func run(ctx context.Context, exampleDir string, out io.Writer) error {
 	support, err := promptkit.CollectionInput(
 		"support",
-		configkit.File("examples/go-library/prepare/collections/support/collection.yaml"),
+		configkit.File(filepath.Join(exampleDir, "collections", "support", "collection.yaml")),
 	)
 	if err != nil {
-		exit(err)
+		return err
 	}
 	review, err := promptkit.CollectionInput(
 		"review",
-		configkit.File("examples/go-library/prepare/collections/review/collection.yaml"),
+		configkit.File(filepath.Join(exampleDir, "collections", "review", "collection.yaml")),
 	)
 	if err != nil {
-		exit(err)
+		return err
 	}
 	override, err := promptkit.CollectionInput(
 		"support",
-		configkit.File("examples/go-library/prepare/collections/support/operator-overrides.yaml"),
+		configkit.File(filepath.Join(exampleDir, "collections", "support", "operator-overrides.yaml")),
 	)
 	if err != nil {
-		exit(err)
+		return err
 	}
 	engine, err := promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{
 		Underlays: []configkit.Underlay{
@@ -56,32 +65,31 @@ func main() {
 		},
 	}})
 	if err != nil {
-		exit(err)
+		return err
 	}
-	ctx := context.Background()
 	scoped, err := engine.WithNamespaces(promptkit.Namespaces{
 		Prompt: "support", Profile: "support", Backend: "support",
 	})
 	if err != nil {
-		exit(err)
+		return err
 	}
 	view, err := engine.InspectConfiguration()
 	if err != nil {
-		exit(err)
+		return err
 	}
 	if _, found := view.Explain(configkit.Keys("collections", "support", "profiles").Index(1).Key("timeout_seconds")); !found {
-		exit(fmt.Errorf("collection profile override was not found"))
+		return fmt.Errorf("collection profile override was not found")
 	}
 	requirements, err := scoped.InspectRequirements(ctx, promptkit.RequirementInspectionRequest{
 		PromptID: "prepare",
 	})
 	if err != nil {
-		exit(err)
+		return err
 	}
 	if !requirements.Complete || len(requirements.Inputs) != 1 ||
 		requirements.Inputs[0].Name != "note" ||
 		requirements.Inputs[0].Kind != promptkit.RequirementRequired {
-		exit(fmt.Errorf("required note input was not discovered before preparation"))
+		return fmt.Errorf("required note input was not discovered before preparation")
 	}
 
 	request := promptkit.RunRequest{
@@ -92,39 +100,39 @@ func main() {
 		},
 	}
 	if err := scoped.ValidateRequest(ctx, request); err != nil {
-		exit(err)
+		return err
 	}
 	prepared, err := scoped.Prepare(ctx, request)
 	if err != nil {
-		exit(err)
+		return err
 	}
 	profile, err := scoped.InspectProfile(ctx, "fast")
 	if err != nil {
-		exit(err)
+		return err
 	}
 	if profile.EffectiveModelParams.TimeoutSeconds != 30 {
-		exit(fmt.Errorf(
+		return fmt.Errorf(
 			"later profile override was not applied: timeout is %d seconds",
 			profile.EffectiveModelParams.TimeoutSeconds,
-		))
+		)
 	}
 	namespaces, err := scoped.ListNamespaces(ctx)
 	if err != nil {
-		exit(err)
+		return err
 	}
 	collections, err := scoped.ListCollections(ctx)
 	if err != nil {
-		exit(err)
+		return err
 	}
 	scopedPrompts, err := scoped.ListPrompts(ctx)
 	if err != nil {
-		exit(err)
+		return err
 	}
 	reviewPrompts, err := scoped.ListPrompts(ctx, promptkit.NamespaceFilter{
 		Mode: promptkit.NamespaceNamed, Name: "review",
 	})
 	if err != nil {
-		exit(err)
+		return err
 	}
 	scopedPromptIDs := make([]string, len(scopedPrompts))
 	for index := range scopedPrompts {
@@ -141,9 +149,9 @@ func main() {
 		}
 	}
 
-	encoder := json.NewEncoder(os.Stdout)
+	encoder := json.NewEncoder(out)
 	encoder.SetIndent("", "  ")
-	if err := encoder.Encode(summary{
+	return encoder.Encode(summary{
 		PromptID:        prepared.PromptID,
 		SelectedProfile: prepared.SelectedProfileID,
 		Model:           prepared.EffectiveModelParams.Model,
@@ -153,12 +161,5 @@ func main() {
 		Collections:     collectionSummaries,
 		ScopedPrompts:   scopedPromptIDs,
 		ReviewPrompts:   reviewPromptIDs,
-	}); err != nil {
-		exit(err)
-	}
-}
-
-func exit(err error) {
-	fmt.Fprintln(os.Stderr, err)
-	os.Exit(1)
+	})
 }
diff --git a/examples/go-library/prepare/main_test.go b/examples/go-library/prepare/main_test.go
new file mode 100644
index 0000000..6247249
--- /dev/null
+++ b/examples/go-library/prepare/main_test.go
@@ -0,0 +1,45 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"reflect"
+	"testing"
+)
+
+func TestPrepareExample(t *testing.T) {
+	var output bytes.Buffer
+	if err := run(t.Context(), ".", &output); err != nil {
+		t.Fatal(err)
+	}
+	var got struct {
+		PromptID      string                       `json:"prompt_id"`
+		Profile       string                       `json:"selected_profile"`
+		Model         string                       `json:"model"`
+		MessageCount  int                          `json:"message_count"`
+		Timeout       int                          `json:"profile_timeout_seconds"`
+		Namespaces    []string                     `json:"namespaces"`
+		Collections   []map[string]json.RawMessage `json:"collections"`
+		ScopedPrompts []string                     `json:"scoped_prompts"`
+		ReviewPrompts []string                     `json:"review_prompts"`
+	}
+	if err := json.Unmarshal(output.Bytes(), &got); err != nil {
+		t.Fatal(err)
+	}
+	if got.PromptID != "support/prepare" || got.Profile != "support/fast" || got.Model != "offline-model" ||
+		got.MessageCount <= 0 || got.Timeout != 30 || !reflect.DeepEqual(got.Namespaces, []string{"review", "support"}) ||
+		!reflect.DeepEqual(got.ScopedPrompts, []string{"support/prepare"}) || !reflect.DeepEqual(got.ReviewPrompts, []string{"review/check"}) || len(got.Collections) != 2 {
+		t.Fatalf("unexpected preparation summary: %+v", got)
+	}
+	for index, want := range []struct{ namespace, release string }{{"review", ""}, {"support", "1.4.0"}} {
+		var namespace string
+		if err := json.Unmarshal(got.Collections[index]["namespace"], &namespace); err != nil || namespace != want.namespace {
+			t.Fatalf("collection namespace = %q, %v", namespace, err)
+		}
+		value, present := got.Collections[index]["release_version"]
+		var release *string
+		if !present || json.Unmarshal(value, &release) != nil || (index == 0 && release != nil) || (index == 1 && (release == nil || *release != want.release)) {
+			t.Fatalf("collection release = %s, present %t; want %q", value, present, want.release)
+		}
+	}
+}