diff --git a/docs/roadmap/implementation.md b/docs/roadmap/implementation.md
index e04f4a5..f488430 100644
--- a/docs/roadmap/implementation.md
+++ b/docs/roadmap/implementation.md
@@ -208,6 +208,11 @@ final validation without adding transitional code or an intermediate gate.
 
 ## Stage 7: Use Prepared Plans For Both Smoke Output Checks
 
+**Completed:** Smoke inference prepares separate JSON and schema plans and
+checks syntax before schema matching. Go 1.27.3 `go test ./internal/usecase
+-run 'Smoke|Diagnostic'` passed, including malformed, scalar, matching,
+nonmatching, cancellation, and dispatch cases.
+
 **Finding:** 4. **Files:** `internal/usecase/smoke_inference_case.go` and diagnostic tests.
 
 1. Replace the smoke case's `jsonValidator validate.Validator` with a
diff --git a/internal/usecase/smoke_inference_case.go b/internal/usecase/smoke_inference_case.go
index 6936e5b..d3aabda 100644
--- a/internal/usecase/smoke_inference_case.go
+++ b/internal/usecase/smoke_inference_case.go
@@ -25,7 +25,7 @@ type smokeInferenceCase struct {
 	kind             domain.SmokeTestKind
 	request          domain.GenerateRequest
 	expectedContent  string
-	jsonValidator    validate.Validator
+	jsonValidation   validate.PreparedValidation
 	schemaValidation validate.PreparedValidation
 }
 
@@ -52,6 +52,12 @@ func prepareSmokeInferenceCase(
 		}, nil
 	case domain.SmokeTestStructuredOutput:
 		validator := validate.NewFSValidator(smokeSchemaFS, ".")
+		jsonPlan, err := validator.PrepareValidation(ctx, domain.OutputContract{
+			Format: domain.FormatJSON, ValidationMode: domain.ValidationJSON,
+		})
+		if err != nil {
+			return nil, fmt.Errorf("%w: prepare private JSON validation: %w", ErrValidation, err)
+		}
 		plan, err := validator.PrepareValidation(ctx, domain.OutputContract{
 			Format:         domain.FormatJSON,
 			ValidationMode: domain.ValidationJSONSchema,
@@ -64,7 +70,7 @@ func prepareSmokeInferenceCase(
 		return &smokeInferenceCase{
 			kind:             kind,
 			expectedContent:  smokeStructuredExpectedContent,
-			jsonValidator:    validate.NewStandardValidator(""),
+			jsonValidation:   jsonPlan,
 			schemaValidation: plan,
 			request: newGenerationRequest(
 				domain.RenderedPrompt{Messages: []domain.RenderedMessage{{Role: "user", Content: smokeStructuredPromptPrefix + smokeStructuredExpectedContent}}},
@@ -97,10 +103,7 @@ func (c *smokeInferenceCase) evaluate(ctx context.Context, response *domain.Gene
 		return facts, nil
 	case domain.SmokeTestStructuredOutput:
 		artifact := domain.Artifact{Body: []byte(response.Content)}
-		jsonResult, err := c.jsonValidator.Validate(ctx, &artifact, domain.OutputContract{
-			Format:         domain.FormatJSON,
-			ValidationMode: domain.ValidationJSON,
-		})
+		jsonResult, err := c.jsonValidation.Validate(ctx, &artifact)
 		if err != nil {
 			return facts, fmt.Errorf("%w: evaluate private smoke-test JSON: %w", ErrValidation, err)
 		}
diff --git a/internal/usecase/smoke_inference_case_test.go b/internal/usecase/smoke_inference_case_test.go
index 7b0bb26..b3607ce 100644
--- a/internal/usecase/smoke_inference_case_test.go
+++ b/internal/usecase/smoke_inference_case_test.go
@@ -2,6 +2,7 @@ package usecase
 
 import (
 	"context"
+	"errors"
 	"reflect"
 	"strings"
 	"testing"
@@ -102,6 +103,7 @@ func TestSmokeStructuredInferenceCaseUsesPrivatePreparedSchema(t *testing.T) {
 	}{
 		{name: "matches", content: caseValue.expectedContent, wantValidJSON: true, wantSchemaMatched: boolPointer(true)},
 		{name: "valid JSON misses schema", content: `{"status":"other"}`, wantValidJSON: true, wantSchemaMatched: boolPointer(false)},
+		{name: "scalar JSON misses schema", content: `42`, wantValidJSON: true, wantSchemaMatched: boolPointer(false)},
 		{name: "additional property misses schema", content: additionalPropertyContent, wantValidJSON: true, wantSchemaMatched: boolPointer(false)},
 		{name: "invalid JSON", content: `{invalid`, wantSchemaMatched: nil},
 		{name: "empty content", content: "", wantSchemaMatched: nil},
@@ -125,3 +127,19 @@ func TestSmokeStructuredInferenceCaseUsesPrivatePreparedSchema(t *testing.T) {
 		t.Fatalf("facts were populated without generated content: %+v", noResponseFacts)
 	}
 }
+
+func TestSmokeStructuredInferenceCaseHonorsCancellation(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+	if _, err := prepareSmokeInferenceCase(ctx, domain.SmokeTestStructuredOutput, domain.SmokeTestTarget{}, 0); !errors.Is(err, context.Canceled) {
+		t.Fatalf("prepare error = %v, want cancellation", err)
+	}
+	caseValue, err := prepareSmokeInferenceCase(context.Background(), domain.SmokeTestStructuredOutput, domain.SmokeTestTarget{}, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	facts, err := caseValue.evaluate(ctx, &domain.GenerateResponse{Content: `{"status":"ok"}`})
+	if !errors.Is(err, context.Canceled) || facts.ValidJSON != nil || facts.SchemaMatched != nil {
+		t.Fatalf("evaluation facts = %+v, error = %v", facts, err)
+	}
+}