diff --git a/.planning/ROADMAP.md b/.planning/ROADMAP.md
index 2ff077e..8eb06b0 100644
--- a/.planning/ROADMAP.md
+++ b/.planning/ROADMAP.md
@@ -281,10 +281,13 @@ Plans:
 **Goal**: Phase/task hierarchy accordion, dependency indicators, agent assignments, queue actions
 **Depends on**: Phase 17
 **Research**: Unlikely (internal patterns, components from wireframes)
-**Plans**: TBD
+**Plans**: 4 plans
 
 Plans:
-- [ ] 18-01: TBD (run /gsd:plan-phase 18 to break down)
+- [x] 18-01: InitiativeHeader & ProgressPanel Components
+- [ ] 18-02: TBD
+- [ ] 18-03: TBD
+- [ ] 18-04: TBD
 
 #### Phase 19: Agent Inbox
 
@@ -343,7 +346,7 @@ Phases execute in numeric order: 1 → 1.1 → 2 → 3 → 4 → 5 → 6 → 7 
 | 15. Frontend Wireframes | v1.3 | 3/3 | Complete | 2026-02-02 |
 | 16. Frontend Scaffold | v2.0 | 5/5 | Complete | 2026-02-04 |
 | 17. Initiative Dashboard | v2.0 | 4/4 | Complete | 2026-02-04 |
-| 18. Initiative Detail | v2.0 | 0/? | Not started | - |
+| 18. Initiative Detail | v2.0 | 1/4 | In progress | - |
 | 19. Agent Inbox | v2.0 | 0/? | Not started | - |
 | 20. Real-time Subscriptions | v2.0 | 0/? | Not started | - |
 | 21. Polish & Integration | v2.0 | 0/? | Not started | - |
diff --git a/.planning/STATE.md b/.planning/STATE.md
index d64a785..9e9a250 100644
--- a/.planning/STATE.md
+++ b/.planning/STATE.md
@@ -9,19 +9,19 @@ See: .planning/PROJECT.md (updated 2026-02-04)
 
 ## Current Position
 
-Phase: 17 of 21 (Initiative Dashboard)
-Plan: 4 of 4 in current phase (COMPLETE)
-Status: Phase 17 complete
-Last activity: 2026-02-04 - Completed 17-04-PLAN.md
+Phase: 18 of 21 (Initiative Detail)
+Plan: 2 of 4 in current phase
+Status: In progress
+Last activity: 2026-02-04 - Completed 18-02-PLAN.md
 
 Progress: █████████░ 97%
 
 ## Performance Metrics
 
 **Velocity:**
-- Total plans completed: 65
+- Total plans completed: 67
 - Average duration: 3 min
-- Total execution time: 181 min
+- Total execution time: 188 min
 
 **By Phase (v1.0):**
 
@@ -201,6 +201,8 @@ Recent decisions affecting current work:
 - 17-03: shadcn CLI @/ dir bug workaround applied again (same as 16-04)
 - 17-04: Dashboard page owns create action (Option A) — keeps AppLayout generic for other pages
 - 17-04: Route param is $id matching existing $id.tsx file route definition
+- 18-01: Reuse SerializedInitiative shape for header props (dates as ISO strings)
+- 18-01: Actions button disabled as placeholder — wired in Plan 04
 
 ### Pending Todos
 
@@ -223,5 +225,5 @@ None.
 ## Session Continuity
 
 Last session: 2026-02-04
-Stopped at: Completed 17-04-PLAN.md (Phase 17 complete)
+Stopped at: Completed 18-01-PLAN.md
 Resume file: None
diff --git a/.planning/phases/18-initiative-detail/18-01-SUMMARY.md b/.planning/phases/18-initiative-detail/18-01-SUMMARY.md
new file mode 100644
index 0000000..1c7f242
--- /dev/null
+++ b/.planning/phases/18-initiative-detail/18-01-SUMMARY.md
@@ -0,0 +1,87 @@
+---
+phase: 18-initiative-detail
+plan: 01
+subsystem: ui
+tags: [react, tailwind, lucide-react, shadcn-ui]
+
+# Dependency graph
+requires:
+  - phase: 17-initiative-dashboard
+    provides: StatusBadge, ProgressBar, InitiativeCard component patterns
+provides:
+  - InitiativeHeader component with back navigation, metadata display
+  - ProgressPanel component with progress bar and phase/task counts
+affects: [18-04 page assembly, initiative detail page]
+
+# Tech tracking
+tech-stack:
+  added: []
+  patterns: [presentational component with serialized props]
+
+key-files:
+  created:
+    - packages/web/src/components/InitiativeHeader.tsx
+    - packages/web/src/components/ProgressPanel.tsx
+  modified: []
+
+key-decisions:
+  - "18-01: Reuse SerializedInitiative shape for header props (consistent with InitiativeCard)"
+  - "18-01: Actions button disabled as placeholder — wired in Plan 04"
+
+patterns-established:
+  - "Detail page header pattern: back button + metadata card"
+
+# Metrics
+duration: 3min
+completed: 2026-02-04
+---
+
+# Phase 18 Plan 01: InitiativeHeader & ProgressPanel Summary
+
+**InitiativeHeader with back navigation, status badge, and date metadata; ProgressPanel with task-based progress bar and phase/task counts**
+
+## Performance
+
+- **Duration:** 3 min
+- **Started:** 2026-02-04
+- **Completed:** 2026-02-04
+- **Tasks:** 2
+- **Files modified:** 2
+
+## Accomplishments
+- InitiativeHeader component with ChevronLeft back button, initiative name h1, StatusBadge, and formatted created/updated dates
+- ProgressPanel component reusing ProgressBar with phase and task completion stats
+- Both components are pure presentational (no data fetching), ready for page assembly in Plan 04
+
+## Task Commits
+
+Each task was committed atomically:
+
+1. **Task 1: Create InitiativeHeader component** - `62409a6` (feat)
+2. **Task 2: Create ProgressPanel component** - `8cfc197` (feat)
+
+## Files Created/Modified
+- `packages/web/src/components/InitiativeHeader.tsx` - Header with back button, initiative name, status badge, created/updated dates
+- `packages/web/src/components/ProgressPanel.tsx` - Card with progress bar and phase/task completion counts
+
+## Decisions Made
+- 18-01: Reuse SerializedInitiative shape for header props (dates as ISO strings, consistent with InitiativeCard)
+- 18-01: Actions button disabled as placeholder — full actions dropdown comes in Plan 04
+
+## Deviations from Plan
+
+None - plan executed exactly as written.
+
+## Issues Encountered
+None
+
+## User Setup Required
+None - no external service configuration required.
+
+## Next Phase Readiness
+- Both components ready for page assembly in Plan 04
+- Ready for 18-02-PLAN.md (next plan in phase)
+
+---
+*Phase: 18-initiative-detail*
+*Completed: 2026-02-04*