feat: acceptance_criteria per story task in elaboration and approval

Add AcceptanceCriteria field to elaboratedStoryTask struct, update
buildStoryElaboratePrompt schema and rules, pass the value through
handleApproveStory into task.Task, and add a test verifying the
field is persisted on approved story tasks.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

3 files changed, 70 insertions, 17 deletions

diff --git a/internal/api/elaborate.go b/internal/api/elaborate.go
index dd51c7d..0cb298d 100644
--- a/internal/api/elaborate.go
+++ b/internal/api/elaborate.go
@@ -282,9 +282,10 @@ type elaboratedStorySubtask struct {
 
 // elaboratedStoryTask is one independently-deployable unit in a story plan.
 type elaboratedStoryTask struct {
-	Name         string                   `json:"name"`
-	Instructions string                   `json:"instructions"`
-	Subtasks     []elaboratedStorySubtask `json:"subtasks"`
+	Name               string                   `json:"name"`
+	Instructions       string                   `json:"instructions"`
+	AcceptanceCriteria string                   `json:"acceptance_criteria"`
+	Subtasks           []elaboratedStorySubtask `json:"subtasks"`
 }
 
 // elaboratedStoryValidation describes how to verify the story was successful.
@@ -313,6 +314,7 @@ Output ONLY valid JSON matching this schema:
     {
       "name": "task name",
       "instructions": "detailed instructions including file paths and what to change",
+      "acceptance_criteria": "specific, verifiable conditions a separate reviewer can check — e.g. 'run go test ./... and verify all pass; confirm GET /api/foo returns 200 with expected JSON shape'",
       "subtasks": [
         { "name": "subtask name", "instructions": "..." }
       ]
@@ -330,7 +332,8 @@ Rules:
 - Subtasks within a task are order-dependent and run sequentially
 - Instructions must include specific file paths, function names, and exact changes
 - Instructions must end with: git add -A && git commit -m "..." && git push origin <branch>
-- Validation should match the scope: small change = build check; new feature = smoke test`
+- Validation should match the scope: small change = build check; new feature = smoke test
+- acceptance_criteria must be concrete and verifiable by a separate agent — no vague assertions like "code looks good"`
 }
 
 func (s *Server) elaborateStoryWithClaude(ctx context.Context, workDir, goal string) (*elaboratedStory, error) {
diff --git a/internal/api/stories.go b/internal/api/stories.go
index 1743dbe..fa10ccd 100644
--- a/internal/api/stories.go
+++ b/internal/api/stories.go
@@ -254,19 +254,20 @@ func (s *Server) handleApproveStory(w http.ResponseWriter, r *http.Request) {
 	var prevTaskID string
 	for _, tp := range input.Tasks {
 		t := &task.Task{
-			ID:            uuid.New().String(),
-			Name:          tp.Name,
-			Project:       input.ProjectID,
-			RepositoryURL: repoURL,
-			StoryID:       story.ID,
-			Agent:         task.AgentConfig{Type: "claude", Instructions: tp.Instructions},
-			Priority:      task.PriorityNormal,
-			Tags:          []string{},
-			DependsOn:     []string{},
-			Retry:         task.RetryConfig{MaxAttempts: 1, Backoff: "exponential"},
-			State:         task.StatePending,
-			CreatedAt:     time.Now().UTC(),
-			UpdatedAt:     time.Now().UTC(),
+			ID:                 uuid.New().String(),
+			Name:               tp.Name,
+			Project:            input.ProjectID,
+			RepositoryURL:      repoURL,
+			StoryID:            story.ID,
+			Agent:              task.AgentConfig{Type: "claude", Instructions: tp.Instructions},
+			AcceptanceCriteria: tp.AcceptanceCriteria,
+			Priority:           task.PriorityNormal,
+			Tags:               []string{},
+			DependsOn:          []string{},
+			Retry:              task.RetryConfig{MaxAttempts: 1, Backoff: "exponential"},
+			State:              task.StatePending,
+			CreatedAt:          time.Now().UTC(),
+			UpdatedAt:          time.Now().UTC(),
 		}
 		if prevTaskID != "" {
 			t.DependsOn = []string{prevTaskID}
diff --git a/internal/api/stories_test.go b/internal/api/stories_test.go
index 342840b..f43ad86 100644
--- a/internal/api/stories_test.go
+++ b/internal/api/stories_test.go
@@ -258,6 +258,55 @@ func TestHandleStoryApprove_SetsRepositoryURL(t *testing.T) {
 	}
 }
 
+func TestApproveStory_AcceptanceCriteriaStored(t *testing.T) {
+	srv, store := testServer(t)
+
+	proj := &task.Project{
+		ID: "ac-proj", Name: "test", RemoteURL: "https://github.com/x/y",
+		Type: "web", DeployScript: "",
+	}
+	store.CreateProject(proj)
+
+	body := `{
+		"name": "AC Story",
+		"branch_name": "story/ac-test",
+		"project_id": "ac-proj",
+		"tasks": [
+			{
+				"name": "Add feature",
+				"instructions": "implement the thing",
+				"acceptance_criteria": "run go test ./... and verify all pass",
+				"subtasks": []
+			}
+		],
+		"validation": {"type": "test", "steps": [], "success_criteria": "tests pass"}
+	}`
+	req := httptest.NewRequest("POST", "/api/stories/approve", strings.NewReader(body))
+	req.Header.Set("Content-Type", "application/json")
+	w := httptest.NewRecorder()
+	srv.mux.ServeHTTP(w, req)
+
+	if w.Code != http.StatusCreated {
+		t.Fatalf("expected 201, got %d: %s", w.Code, w.Body.String())
+	}
+
+	var resp struct {
+		TaskIDs []string `json:"task_ids"`
+	}
+	json.NewDecoder(w.Body).Decode(&resp)
+	if len(resp.TaskIDs) == 0 {
+		t.Fatal("expected task_ids in response")
+	}
+
+	tk, err := store.GetTask(resp.TaskIDs[0])
+	if err != nil {
+		t.Fatalf("GetTask: %v", err)
+	}
+	if tk.AcceptanceCriteria != "run go test ./... and verify all pass" {
+		t.Errorf("expected acceptance criteria stored on task, got %q", tk.AcceptanceCriteria)
+	}
+}
+
 func TestHandleStoryDeploymentStatus(t *testing.T) {
 	srv, store := testServer(t)