Implement manifest model and local store

internal/app/commands_test.go

@@ -2,14 +2,19 @@ package app
 
 import (
 	"bytes"
+	"context"
 	"os"
 	"path/filepath"
 	"strings"
 	"testing"
+	"time"
+
+	"gitea.maximumdirect.net/eric/narratio/internal/manifest"
 )
 
 func TestExecuteValidCommands(t *testing.T) {
 	pipelinePath, sessionPath := writeValidConfigFiles(t)
+	manifestPath := writeManifestPathForExecute(t)
 
 	cases := []struct {
 		name    string
@@ -18,7 +23,7 @@ func TestExecuteValidCommands(t *testing.T) {
 	}{
 		{name: "run", args: []string{"run", "--config", pipelinePath, "--session", sessionPath}, wantOut: "narratio run: configuration loaded and valid"},
 		{name: "plan", args: []string{"plan", "--config", pipelinePath, "--session", sessionPath}, wantOut: "narratio plan: configuration loaded and valid"},
-		{name: "status", args: []string{"status"}, wantOut: "narratio status: not yet implemented"},
+		{name: "status", args: []string{"status", "--manifest", manifestPath}, wantOut: "session_id: 2026-05-03"},
 		{name: "resume", args: []string{"resume"}, wantOut: "narratio resume: not yet implemented"},
 		{name: "run-stage", args: []string{"run-stage", "polish"}, wantOut: "narratio run-stage: not yet implemented"},
 	}
@@ -42,7 +47,7 @@ func TestExecuteValidCommands(t *testing.T) {
 	}
 }
 
-func TestExecuteMissingConfigFlags(t *testing.T) {
+func TestExecuteMissingRequiredFlags(t *testing.T) {
 	cases := []struct {
 		name string
 		args []string
@@ -50,6 +55,7 @@ func TestExecuteMissingConfigFlags(t *testing.T) {
 	}{
 		{name: "run missing flags", args: []string{"run"}, want: "run: --config and --session are required"},
 		{name: "plan missing flags", args: []string{"plan"}, want: "plan: --config and --session are required"},
+		{name: "status missing flags", args: []string{"status"}, want: "status: --manifest is required"},
 	}
 
 	for _, tc := range cases {
@@ -149,3 +155,18 @@ inputs:
 
 	return pipelinePath, sessionPath
 }
+
+func writeManifestPathForExecute(t *testing.T) string {
+	t.Helper()
+
+	store := &manifest.LocalStore{}
+	m := manifest.New("2026-05-03", time.Date(2026, 5, 3, 10, 0, 0, 0, time.UTC))
+	m.MarkStageSucceeded("prepare", time.Date(2026, 5, 3, 10, 1, 0, 0, time.UTC), nil)
+
+	path := filepath.Join(t.TempDir(), "manifest.json")
+	if err := store.Save(context.Background(), path, m); err != nil {
+		t.Fatalf("save manifest: %v", err)
+	}
+
+	return path
+}

internal/app/status.go

@@ -2,10 +2,66 @@ package app
 
 import (
 	"context"
+	"flag"
+	"fmt"
 	"io"
+	"sort"
+
+	"gitea.maximumdirect.net/eric/narratio/internal/manifest"
 )
 
-// Status is a placeholder for future manifest status inspection behavior.
-func Status(_ context.Context, _ []string, out io.Writer) error {
-	return placeholder(out, "status")
+// Status reads and prints stage statuses from an existing manifest.
+func Status(ctx context.Context, args []string, out io.Writer) error {
+	fs := flag.NewFlagSet("status", flag.ContinueOnError)
+	fs.SetOutput(io.Discard)
+
+	var manifestPath string
+	fs.StringVar(&manifestPath, "manifest", "", "path to manifest.json")
+
+	if err := fs.Parse(args); err != nil {
+		return fmt.Errorf("status: invalid flags: %w", err)
+	}
+	if fs.NArg() != 0 {
+		return fmt.Errorf("status: unexpected positional arguments")
+	}
+	if manifestPath == "" {
+		return fmt.Errorf("status: --manifest is required")
+	}
+
+	store := &manifest.LocalStore{}
+	m, err := store.Load(ctx, manifestPath)
+	if err != nil {
+		return fmt.Errorf("status: %w", err)
+	}
+
+	if _, err := fmt.Fprintf(out, "session_id: %s\n", m.SessionID); err != nil {
+		return err
+	}
+	if _, err := fmt.Fprintf(out, "updated_at: %s\n", m.UpdatedAt.UTC().Format("2006-01-02T15:04:05Z07:00")); err != nil {
+		return err
+	}
+
+	if len(m.Stages) == 0 {
+		_, err := fmt.Fprintln(out, "stages: no stages recorded")
+		return err
+	}
+
+	if _, err := fmt.Fprintln(out, "stages:"); err != nil {
+		return err
+	}
+
+	names := make([]string, 0, len(m.Stages))
+	for name := range m.Stages {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+
+	for _, name := range names {
+		status := m.Stages[name].Status
+		if _, err := fmt.Fprintf(out, "- %s: %s\n", name, status); err != nil {
+			return err
+		}
+	}
+
+	return nil
 }

internal/app/status_test.go

@@ -0,0 +1,73 @@
+package app
+
+import (
+	"bytes"
+	"context"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+
+	"gitea.maximumdirect.net/eric/narratio/internal/manifest"
+)
+
+func TestStatusCommandReadsManifest(t *testing.T) {
+	manifestPath := writeManifestForStatus(t)
+
+	var out bytes.Buffer
+	err := Status(context.Background(), []string{"--manifest", manifestPath}, &out)
+	if err != nil {
+		t.Fatalf("Status() error = %v", err)
+	}
+
+	s := out.String()
+	if !strings.Contains(s, "session_id: 2026-05-03") {
+		t.Fatalf("output = %q, want session_id", s)
+	}
+	if !strings.Contains(s, "- merge: succeeded") {
+		t.Fatalf("output = %q, want stage status", s)
+	}
+}
+
+func TestStatusCommandMissingManifestFlag(t *testing.T) {
+	var out bytes.Buffer
+	err := Status(context.Background(), nil, &out)
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+	if !strings.Contains(err.Error(), "--manifest is required") {
+		t.Fatalf("error = %q, want missing manifest flag", err.Error())
+	}
+}
+
+func TestStatusCommandBadManifest(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "manifest.json")
+	if err := os.WriteFile(path, []byte("{not-json"), 0o644); err != nil {
+		t.Fatalf("WriteFile() error = %v", err)
+	}
+
+	var out bytes.Buffer
+	err := Status(context.Background(), []string{"--manifest", path}, &out)
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+	if !strings.Contains(err.Error(), "decode manifest") {
+		t.Fatalf("error = %q, want decode error", err.Error())
+	}
+}
+
+func writeManifestForStatus(t *testing.T) string {
+	t.Helper()
+
+	store := &manifest.LocalStore{}
+	m := manifest.New("2026-05-03", time.Date(2026, 5, 3, 10, 0, 0, 0, time.UTC))
+	m.MarkStageSucceeded("merge", time.Date(2026, 5, 3, 10, 5, 0, 0, time.UTC), nil)
+
+	path := filepath.Join(t.TempDir(), "manifest.json")
+	if err := store.Save(context.Background(), path, m); err != nil {
+		t.Fatalf("Save() error = %v", err)
+	}
+	return path
+}

internal/manifest/manifest.go

@@ -1,18 +1,140 @@
 package manifest
 
-import "time"
+import (
+	"strings"
+	"time"
+)
 
-// StageState tracks status and metadata for one stage execution.
-type StageState struct {
-	Status    StageStatus
-	UpdatedAt time.Time
-	Error     string
+// ErrorRecord captures structured error metadata at run or stage scope.
+type ErrorRecord struct {
+	Message string     `json:"message"`
+	Code    string     `json:"code,omitempty"`
+	At      *time.Time `json:"at,omitempty"`
 }
 
-// Manifest is the durable state record for a session run.
+// InputRecord captures one resolved input and optional checksum.
+type InputRecord struct {
+	Kind     string `json:"kind"`
+	Path     string `json:"path"`
+	Checksum string `json:"checksum,omitempty"`
+}
+
+// ArtifactRecord captures one produced artifact and optional remote metadata.
+type ArtifactRecord struct {
+	Kind      string `json:"kind"`
+	LocalPath string `json:"local_path"`
+	RemoteKey string `json:"remote_key,omitempty"`
+	Checksum  string `json:"checksum,omitempty"`
+}
+
+// StageRecord tracks lifecycle and provenance for one pipeline stage.
+type StageRecord struct {
+	Name             string           `json:"name"`
+	Status           StageStatus      `json:"status"`
+	CreatedAt        time.Time        `json:"created_at"`
+	UpdatedAt        time.Time        `json:"updated_at"`
+	StartedAt        *time.Time       `json:"started_at,omitempty"`
+	CompletedAt      *time.Time       `json:"completed_at,omitempty"`
+	Outputs          []ArtifactRecord `json:"outputs,omitempty"`
+	Logs             []string         `json:"logs,omitempty"`
+	GeneratedConfigs []string         `json:"generated_configs,omitempty"`
+	Error            *ErrorRecord     `json:"error,omitempty"`
+	Metadata         map[string]any   `json:"metadata,omitempty"`
+}
+
+// Manifest is the durable run-state record for a session execution.
 type Manifest struct {
-	SessionID string
-	CreatedAt time.Time
-	UpdatedAt time.Time
-	Stages    map[string]StageState
+	SessionID       string                  `json:"session_id"`
+	PipelineVersion string                  `json:"pipeline_version,omitempty"`
+	CreatedAt       time.Time               `json:"created_at"`
+	UpdatedAt       time.Time               `json:"updated_at"`
+	LastError       *ErrorRecord            `json:"last_error,omitempty"`
+	Inputs          []InputRecord           `json:"inputs,omitempty"`
+	Artifacts       []ArtifactRecord        `json:"artifacts,omitempty"`
+	Stages          map[string]*StageRecord `json:"stages"`
+}
+
+// New constructs a new manifest with deterministic timestamps.
+func New(sessionID string, now time.Time) *Manifest {
+	return &Manifest{
+		SessionID: strings.TrimSpace(sessionID),
+		CreatedAt: now,
+		UpdatedAt: now,
+		Stages:    map[string]*StageRecord{},
+	}
+}
+
+// MarkStageRunning marks a stage as running and updates timestamps.
+func (m *Manifest) MarkStageRunning(name string, at time.Time) {
+	s := m.ensureStage(name, at)
+	s.Status = StatusRunning
+	s.StartedAt = timePtr(at)
+	s.CompletedAt = nil
+	s.Error = nil
+	s.UpdatedAt = at
+	m.UpdatedAt = at
+}
+
+// MarkStageSucceeded marks a stage as succeeded, stores outputs, and updates timestamps.
+func (m *Manifest) MarkStageSucceeded(name string, at time.Time, outputs []ArtifactRecord) {
+	s := m.ensureStage(name, at)
+	s.Status = StatusSucceeded
+	s.CompletedAt = timePtr(at)
+	s.Error = nil
+	s.Outputs = append([]ArtifactRecord(nil), outputs...)
+	s.UpdatedAt = at
+	m.UpdatedAt = at
+}
+
+// MarkStageFailed marks a stage as failed and records error metadata.
+func (m *Manifest) MarkStageFailed(name string, at time.Time, message string) {
+	s := m.ensureStage(name, at)
+	s.Status = StatusFailed
+	s.CompletedAt = timePtr(at)
+	s.Error = &ErrorRecord{Message: strings.TrimSpace(message), At: timePtr(at)}
+	s.UpdatedAt = at
+	m.LastError = &ErrorRecord{Message: strings.TrimSpace(message), At: timePtr(at)}
+	m.UpdatedAt = at
+}
+
+// MarkStageSkipped marks a stage as skipped and records the skip reason.
+func (m *Manifest) MarkStageSkipped(name string, at time.Time, reason string) {
+	s := m.ensureStage(name, at)
+	s.Status = StatusSkipped
+	s.CompletedAt = timePtr(at)
+	s.Error = &ErrorRecord{Message: strings.TrimSpace(reason), Code: "skipped", At: timePtr(at)}
+	s.UpdatedAt = at
+	m.UpdatedAt = at
+}
+
+func (m *Manifest) ensureStage(name string, at time.Time) *StageRecord {
+	if m.Stages == nil {
+		m.Stages = map[string]*StageRecord{}
+	}
+
+	stageName := strings.TrimSpace(name)
+	s, ok := m.Stages[stageName]
+	if !ok || s == nil {
+		s = &StageRecord{
+			Name:      stageName,
+			Status:    StatusPending,
+			CreatedAt: at,
+			UpdatedAt: at,
+		}
+		m.Stages[stageName] = s
+	}
+
+	if s.Name == "" {
+		s.Name = stageName
+	}
+	if s.CreatedAt.IsZero() {
+		s.CreatedAt = at
+	}
+
+	return s
+}
+
+func timePtr(t time.Time) *time.Time {
+	v := t
+	return &v
 }

internal/manifest/manifest_test.go

@@ -0,0 +1,66 @@
+package manifest
+
+import (
+	"testing"
+	"time"
+)
+
+func TestStageMarkHelpers(t *testing.T) {
+	m := New("2026-05-03", time.Date(2026, 5, 3, 12, 0, 0, 0, time.UTC))
+
+	runningAt := time.Date(2026, 5, 3, 12, 1, 0, 0, time.UTC)
+	m.MarkStageRunning("transcribe", runningAt)
+
+	stage := m.Stages["transcribe"]
+	if stage == nil {
+		t.Fatal("stage not created")
+	}
+	if stage.Status != StatusRunning {
+		t.Fatalf("status = %q, want %q", stage.Status, StatusRunning)
+	}
+	if stage.StartedAt == nil || !stage.StartedAt.Equal(runningAt) {
+		t.Fatalf("started_at = %v, want %v", stage.StartedAt, runningAt)
+	}
+
+	succeededAt := runningAt.Add(2 * time.Minute)
+	outputs := []ArtifactRecord{{Kind: "processed_transcript", LocalPath: "transcripts/processed.json"}}
+	m.MarkStageSucceeded("transcribe", succeededAt, outputs)
+	if stage.Status != StatusSucceeded {
+		t.Fatalf("status = %q, want %q", stage.Status, StatusSucceeded)
+	}
+	if stage.CompletedAt == nil || !stage.CompletedAt.Equal(succeededAt) {
+		t.Fatalf("completed_at = %v, want %v", stage.CompletedAt, succeededAt)
+	}
+	if len(stage.Outputs) != 1 {
+		t.Fatalf("outputs len = %d, want 1", len(stage.Outputs))
+	}
+
+	failedAt := succeededAt.Add(1 * time.Minute)
+	m.MarkStageFailed("analyze", failedAt, "analyzer crashed")
+	failed := m.Stages["analyze"]
+	if failed == nil {
+		t.Fatal("failed stage missing")
+	}
+	if failed.Status != StatusFailed {
+		t.Fatalf("status = %q, want %q", failed.Status, StatusFailed)
+	}
+	if failed.Error == nil || failed.Error.Message != "analyzer crashed" {
+		t.Fatalf("error = %#v, want message", failed.Error)
+	}
+
+	skippedAt := failedAt.Add(1 * time.Minute)
+	m.MarkStageSkipped("notify", skippedAt, "notifications disabled")
+	skipped := m.Stages["notify"]
+	if skipped == nil {
+		t.Fatal("skipped stage missing")
+	}
+	if skipped.Status != StatusSkipped {
+		t.Fatalf("status = %q, want %q", skipped.Status, StatusSkipped)
+	}
+	if skipped.Error == nil || skipped.Error.Message != "notifications disabled" {
+		t.Fatalf("error = %#v, want skip reason", skipped.Error)
+	}
+	if skipped.Error.Code != "skipped" {
+		t.Fatalf("error code = %q, want %q", skipped.Error.Code, "skipped")
+	}
+}

internal/manifest/store.go

@@ -2,26 +2,173 @@ package manifest
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
 )
 
-// Store is a placeholder interface for manifest persistence.
+// Store persists manifests to and from durable storage.
 type Store interface {
-	Load(ctx context.Context, sessionID string) (*Manifest, error)
-	Save(ctx context.Context, m *Manifest) error
+	Create(ctx context.Context, sessionID string) (*Manifest, error)
+	Load(ctx context.Context, path string) (*Manifest, error)
+	Save(ctx context.Context, path string, m *Manifest) error
 }
 
-// LocalStore is a placeholder local-filesystem manifest store.
-type LocalStore struct {
-	RootDir string
+// LocalStore stores manifests as JSON on the local filesystem.
+type LocalStore struct{}
+
+// Create returns a new in-memory manifest for a session.
+func (s *LocalStore) Create(ctx context.Context, sessionID string) (*Manifest, error) {
+	if err := checkContext(ctx); err != nil {
+		return nil, err
+	}
+	if strings.TrimSpace(sessionID) == "" {
+		return nil, fmt.Errorf("create manifest: sessionID is required")
+	}
+
+	now := time.Now().UTC()
+	return New(sessionID, now), nil
 }
 
-// Load returns a not-yet-implemented error in the scaffold.
-func (s *LocalStore) Load(_ context.Context, _ string) (*Manifest, error) {
-	return nil, fmt.Errorf("manifest local load: not yet implemented")
+// Load reads and validates a local JSON manifest from path.
+func (s *LocalStore) Load(ctx context.Context, path string) (*Manifest, error) {
+	if err := checkContext(ctx); err != nil {
+		return nil, err
+	}
+	if strings.TrimSpace(path) == "" {
+		return nil, fmt.Errorf("load manifest: path is required")
+	}
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("load manifest %q: %w", path, err)
+	}
+
+	var m Manifest
+	if err := json.Unmarshal(data, &m); err != nil {
+		return nil, fmt.Errorf("decode manifest %q: %w", path, err)
+	}
+
+	if err := validateLoadedManifest(&m); err != nil {
+		return nil, fmt.Errorf("manifest %q invalid: %w", path, err)
+	}
+	normalizeManifest(&m)
+
+	return &m, nil
 }
 
-// Save returns a not-yet-implemented error in the scaffold.
-func (s *LocalStore) Save(_ context.Context, _ *Manifest) error {
-	return fmt.Errorf("manifest local save: not yet implemented")
+// Save writes the manifest to path atomically via temp file + rename.
+func (s *LocalStore) Save(ctx context.Context, path string, m *Manifest) error {
+	if err := checkContext(ctx); err != nil {
+		return err
+	}
+	if strings.TrimSpace(path) == "" {
+		return fmt.Errorf("save manifest: path is required")
+	}
+	if m == nil {
+		return fmt.Errorf("save manifest: manifest is nil")
+	}
+	if strings.TrimSpace(m.SessionID) == "" {
+		return fmt.Errorf("save manifest: session_id is required")
+	}
+	if m.CreatedAt.IsZero() {
+		return fmt.Errorf("save manifest: created_at is required")
+	}
+
+	m.UpdatedAt = time.Now().UTC()
+	if m.Stages == nil {
+		m.Stages = map[string]*StageRecord{}
+	}
+
+	data, err := json.MarshalIndent(m, "", "  ")
+	if err != nil {
+		return fmt.Errorf("save manifest: marshal: %w", err)
+	}
+	data = append(data, '\n')
+
+	dir := filepath.Dir(path)
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		return fmt.Errorf("save manifest: create directory %q: %w", dir, err)
+	}
+
+	tmp, err := os.CreateTemp(dir, ".manifest.json.tmp-*")
+	if err != nil {
+		return fmt.Errorf("save manifest: create temp file: %w", err)
+	}
+	tmpName := tmp.Name()
+	removeTmp := true
+	defer func() {
+		if removeTmp {
+			_ = os.Remove(tmpName)
+		}
+	}()
+
+	if _, err := tmp.Write(data); err != nil {
+		_ = tmp.Close()
+		return fmt.Errorf("save manifest: write temp file: %w", err)
+	}
+	if err := tmp.Sync(); err != nil {
+		_ = tmp.Close()
+		return fmt.Errorf("save manifest: sync temp file: %w", err)
+	}
+	if err := tmp.Close(); err != nil {
+		return fmt.Errorf("save manifest: close temp file: %w", err)
+	}
+	if err := checkContext(ctx); err != nil {
+		return err
+	}
+
+	if err := os.Rename(tmpName, path); err != nil {
+		return fmt.Errorf("save manifest: rename temp file: %w", err)
+	}
+	removeTmp = false
+
+	return nil
+}
+
+func validateLoadedManifest(m *Manifest) error {
+	if m == nil {
+		return fmt.Errorf("manifest is nil")
+	}
+	if strings.TrimSpace(m.SessionID) == "" {
+		return fmt.Errorf("session_id is required")
+	}
+	if m.CreatedAt.IsZero() {
+		return fmt.Errorf("created_at is required")
+	}
+	if m.UpdatedAt.IsZero() {
+		return fmt.Errorf("updated_at is required")
+	}
+
+	return nil
+}
+
+func normalizeManifest(m *Manifest) {
+	if m.Stages == nil {
+		m.Stages = map[string]*StageRecord{}
+	}
+	for name, stage := range m.Stages {
+		if stage == nil {
+			stage = &StageRecord{Name: name, Status: StatusPending, CreatedAt: m.CreatedAt, UpdatedAt: m.UpdatedAt}
+			m.Stages[name] = stage
+		}
+		if stage.Name == "" {
+			stage.Name = name
+		}
+	}
+}
+
+func checkContext(ctx context.Context) error {
+	if ctx == nil {
+		return nil
+	}
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+		return nil
+	}
 }

internal/manifest/store_test.go

@@ -0,0 +1,139 @@
+package manifest
+
+import (
+	"context"
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestLocalStoreCreateSaveLoadRoundTrip(t *testing.T) {
+	store := &LocalStore{}
+	ctx := context.Background()
+
+	m, err := store.Create(ctx, "2026-05-03")
+	if err != nil {
+		t.Fatalf("Create() error = %v", err)
+	}
+
+	now := time.Date(2026, 5, 3, 12, 0, 0, 0, time.UTC)
+	m.MarkStageRunning("prepare", now)
+	m.MarkStageSucceeded("prepare", now.Add(2*time.Second), []ArtifactRecord{{Kind: "transcript", LocalPath: "transcripts/merged.json"}})
+
+	path := filepath.Join(t.TempDir(), "manifest.json")
+	if err := store.Save(ctx, path, m); err != nil {
+		t.Fatalf("Save() error = %v", err)
+	}
+
+	loaded, err := store.Load(ctx, path)
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+
+	if loaded.SessionID != "2026-05-03" {
+		t.Fatalf("SessionID = %q, want %q", loaded.SessionID, "2026-05-03")
+	}
+	stage, ok := loaded.Stages["prepare"]
+	if !ok {
+		t.Fatalf("stage prepare not found")
+	}
+	if stage.Status != StatusSucceeded {
+		t.Fatalf("status = %q, want %q", stage.Status, StatusSucceeded)
+	}
+	if len(stage.Outputs) != 1 {
+		t.Fatalf("outputs len = %d, want 1", len(stage.Outputs))
+	}
+	if loaded.UpdatedAt.IsZero() {
+		t.Fatal("UpdatedAt is zero")
+	}
+}
+
+func TestLocalStoreSaveUpdatesTimestamp(t *testing.T) {
+	store := &LocalStore{}
+	ctx := context.Background()
+
+	createdAt := time.Date(2026, 5, 3, 10, 0, 0, 0, time.UTC)
+	m := New("2026-05-03", createdAt)
+	m.UpdatedAt = createdAt
+
+	path := filepath.Join(t.TempDir(), "manifest.json")
+	if err := store.Save(ctx, path, m); err != nil {
+		t.Fatalf("first Save() error = %v", err)
+	}
+	firstUpdated := m.UpdatedAt
+
+	time.Sleep(5 * time.Millisecond)
+	if err := store.Save(ctx, path, m); err != nil {
+		t.Fatalf("second Save() error = %v", err)
+	}
+
+	if !m.UpdatedAt.After(firstUpdated) {
+		t.Fatalf("UpdatedAt = %v, want after %v", m.UpdatedAt, firstUpdated)
+	}
+}
+
+func TestLocalStoreSaveAtomicPractical(t *testing.T) {
+	store := &LocalStore{}
+	ctx := context.Background()
+
+	dir := t.TempDir()
+	path := filepath.Join(dir, "manifest.json")
+
+	m := New("session-a", time.Date(2026, 5, 3, 10, 0, 0, 0, time.UTC))
+	if err := store.Save(ctx, path, m); err != nil {
+		t.Fatalf("Save() error = %v", err)
+	}
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("ReadFile() error = %v", err)
+	}
+	var decoded Manifest
+	if err := json.Unmarshal(data, &decoded); err != nil {
+		t.Fatalf("saved manifest is not valid JSON: %v", err)
+	}
+
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		t.Fatalf("ReadDir() error = %v", err)
+	}
+	for _, e := range entries {
+		if strings.HasPrefix(e.Name(), ".manifest.json.tmp-") {
+			t.Fatalf("found unexpected temp file after save: %s", e.Name())
+		}
+	}
+
+	m.SessionID = "session-b"
+	if err := store.Save(ctx, path, m); err != nil {
+		t.Fatalf("second Save() error = %v", err)
+	}
+
+	loaded, err := store.Load(ctx, path)
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+	if loaded.SessionID != "session-b" {
+		t.Fatalf("SessionID = %q, want %q", loaded.SessionID, "session-b")
+	}
+}
+
+func TestLoadRejectsInvalidManifest(t *testing.T) {
+	store := &LocalStore{}
+	ctx := context.Background()
+
+	path := filepath.Join(t.TempDir(), "manifest.json")
+	if err := os.WriteFile(path, []byte(`{"updated_at":"2026-05-03T10:00:00Z"}`), 0o644); err != nil {
+		t.Fatalf("WriteFile() error = %v", err)
+	}
+
+	_, err := store.Load(ctx, path)
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+	if !strings.Contains(err.Error(), "session_id is required") {
+		t.Fatalf("error = %q, want session_id validation", err.Error())
+	}
+}