fix(store): TaskAmended applies description/priority/due, not just title (S7)

Amendments to due/description/inherent_priority were accepted and durably
logged but silently discarded by the projection since store.apply only
ever handled the title key. Also added the missing Task.Description field
(TaskCreated never populated it either).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W1rkJ2hBMybnJctPbcy4tT

AUDIT.md

@@ -867,6 +867,21 @@ both come through in the brief.
 
 `go build ./...`, `go vet ./...`, `go test ./...` all pass.
 
+### S7 — closed, 2026-07-27
+
+`store.apply`'s `TaskAmended` case only ever applied `title` from the
+amendment payload — `due`, `description`, and `inherent_priority` amendments
+were accepted by `ValidatePayload` (which only checks the payload is
+non-empty) and durably logged, but silently dropped by the projection, so a
+client reading back the task would never see them take effect. Also found in
+passing: `domain.Task` had no `Description` field at all, so a description
+couldn't be amended onto a task even if the projection had handled it —
+`TaskCreated` discarded it too. Added `Task.Description`; both `TaskCreated`
+and `TaskAmended` in `store.apply` now populate/update all four fields
+(`title`, `description`, `inherent_priority`, `due`), matching what §4 lists
+as amendable. Covered by `TestTaskAmendedAppliesAllFields`
+(`internal/store/store_test.go`).
+
 ### Design consequences (not yet implemented)
 
 1. **Percentages are a level, not a delta.**

internal/domain/domain.go

@@ -61,6 +61,7 @@ type Task struct {
 	Lease            *Lease     `json:"lease,omitempty"`
 	Version          int        `json:"version"`
 	Title            string     `json:"title,omitempty"`
+	Description      string     `json:"description,omitempty"`
 }
 
 type Event struct {

internal/store/store.go

@@ -135,6 +135,9 @@ func (s *Store) apply(e domain.Event) error {
 		if v, ok := p["title"].(string); ok {
 			t.Title = v
 		}
+		if v, ok := p["description"].(string); ok {
+			t.Description = v
+		}
 		s.external[t.Source+"\x00"+t.ExternalID] = t.ID
 	case "TaskLeased":
 		t.State = domain.StateLeased
@@ -152,9 +155,18 @@ func (s *Store) apply(e domain.Event) error {
 		t.State = domain.StateBlocked
 		t.Lease = nil
 	case "TaskAmended":
-		for k, v := range p {
-			if k == "title" {
-				t.Title, v = v.(string)
+		if v, ok := p["title"].(string); ok {
+			t.Title = v
+		}
+		if v, ok := p["description"].(string); ok {
+			t.Description = v
+		}
+		if v, ok := p["inherent_priority"].(float64); ok {
+			t.InherentPriority = int(v)
+		}
+		if v, ok := p["due"].(string); ok {
+			if d, err := time.Parse(time.RFC3339, v); err == nil {
+				t.Due = &d
 			}
 		}
 	}

internal/store/store_test.go

@@ -55,6 +55,37 @@ func TestAppendReplayAndDeduplicate(t *testing.T) {
 	}
 }
 
+// TestTaskAmendedAppliesAllFields guards S7: the projection previously only
+// applied "title" from a TaskAmended payload, silently discarding due,
+// description, and inherent_priority amendments even though they were
+// accepted and logged.
+func TestTaskAmendedAppliesAllFields(t *testing.T) {
+	dir := t.TempDir()
+	s, err := Open(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := s.Append(created("e1")); err != nil {
+		t.Fatal(err)
+	}
+	amend, _ := json.Marshal(map[string]any{
+		"title":             "new title",
+		"description":       "new description",
+		"inherent_priority": 5.0,
+		"due":               "2026-08-01T00:00:00Z",
+	})
+	if err := s.Append(domain.Event{Type: "TaskAmended", TaskID: "task-1", Version: 2, Payload: amend, Surface: string(authz.System)}); err != nil {
+		t.Fatal(err)
+	}
+	tk := s.Tasks()[0]
+	if tk.Title != "new title" || tk.Description != "new description" || tk.InherentPriority != 5 {
+		t.Fatalf("unexpected task after amendment: %+v", tk)
+	}
+	if tk.Due == nil || !tk.Due.Equal(time.Date(2026, 8, 1, 0, 0, 0, 0, time.UTC)) {
+		t.Fatalf("unexpected due after amendment: %+v", tk.Due)
+	}
+}
+
 // TestLeaseAndExpireEventIDsAreUnique guards S5: Event.ID was set to the
 // task id in both Lease and ExpireLeases, so every lease of the same task
 // produced a TaskLeased/TaskReleased event with a colliding ID — unsound

progress.md

@@ -219,7 +219,14 @@ Fixed so far:
   `receipt` straight out of each `TaskCompleted` event's existing payload.
   Covered by an updated `TestBuildBrief`.
 
-Not yet started: Codex/opencode completion producers, S7–S11. See
+- **S7** — `TaskAmended` only ever applied `title` from the amendment
+  payload; `due`/`description`/`inherent_priority` amendments were accepted
+  and logged but silently dropped by the projection. Also added the missing
+  `Task.Description` field (it didn't exist at all, so `TaskCreated` dropped
+  it too). Both `TaskCreated` and `TaskAmended` now populate all four fields.
+  Covered by `TestTaskAmendedAppliesAllFields` (`internal/store`).
+
+Not yet started: Codex/opencode completion producers, S8–S11. See
 `AUDIT.md` for the full plan.
 
 **Phase 0 done (2026-07-27):** this box has live TCP reachability to the real