diff --git a/context/architecture.md b/context/architecture.md
index 5ed140f6..1871804d 100644
--- a/context/architecture.md
+++ b/context/architecture.md
@@ -1,5 +1,33 @@
 # Architecture Reference
 
+## Architecture Programme Status
+
+### Discovery Status
+
+Complete
+
+### Current Phase
+
+Adoption Planning
+
+### Current Proven Business Decision Models
+
+- Appeal Type Policy
+- Representation Entry Policy
+- Representation Type Availability
+
+### Next Recommended Architecture Stream
+
+Portal API Security & Access Boundary Assessment
+
+### Objectives
+
+- endpoint inventory
+- authenticated/public classification
+- ownership validation review
+- access-control consistency review
+- security boundary assessment
+
 ## Runtime Topology
 
 1. Next.js runtime serves UI routes and API routes (legacy custom server files are present but not active).
diff --git a/context/remaining-architecture-candidates.md b/context/remaining-architecture-candidates.md
index 6e106115..6cacd2cd 100644
--- a/context/remaining-architecture-candidates.md
+++ b/context/remaining-architecture-candidates.md
@@ -10,6 +10,8 @@ The PEDW architectural discovery programme is considered complete for practical
 
 No strong undiscovered business-policy candidates remain.
 
+No major undiscovered architectural business-policy candidates remain in the current portal scope.
+
 Future architectural work should focus on:
 
 - documentation consolidation
@@ -20,6 +22,8 @@ Future architectural work should focus on:
 
 rather than broad architectural discovery.
 
+Future architecture work should therefore be treated as adoption-planning and assurance work, not as reopening the discovery programme.
+
 ---
 
 ## Final Architectural Classification
@@ -879,6 +883,21 @@ Primary focus:
 
 ---
 
+## Recommended Next Architecture Stream
+
+Portal API Security & Access Boundary Assessment
+
+Suggested investigation areas:
+
+- endpoint inventory
+- ownership enforcement review
+- authenticated/public endpoint classification
+- access-control consistency assessment
+
+This is intended as the highest-value next architecture stream after discovery close-out and should be treated as a focused security/access-boundary review rather than as a new business-policy discovery track.
+
+---
+
 ### Recommended Next Verification Slice
 
 **Appeal Type Availability Filtering Verification**
diff --git a/memory-bank/architect-review.md b/memory-bank/architect-review.md
index 356cb597..3130f8a5 100644
--- a/memory-bank/architect-review.md
+++ b/memory-bank/architect-review.md
@@ -1,5 +1,45 @@
 Absolutely — here’s a senior architecture review of this repository.
 
+## Architecture Programme Outcome (June 2026)
+
+### Business Decision Models
+
+- Appeal Type Policy
+- Representation Entry Policy
+- Representation Type Availability
+
+### Presentation Models
+
+- Dashboard Policy
+- Case Lifecycle / Journey Interpretation
+- Welsh Lookup Translation
+
+### CRM Compatibility Models
+
+- Query Profiles
+- CRM Compatibility
+- Specialist Process Compatibility
+
+### Workflow / Integration Models
+
+- Submission Behaviour
+- Notification Behaviour
+- New Appeal Start & Resume Behaviour
+
+### Conclusion
+
+The architecture increasingly resembles:
+
+Compatibility Layer
+↓
+Adapter Layer
+↓
+Business Policy
+↓
+Presentation Layer
+
+rather than large hidden domain models distributed throughout the application.
+
 ## Update: TASK22211 completed slice (2026-03-23)
 
 - Branch: `TASK22211-endpoint-search-document-contract-consistency`
diff --git a/memory-bank/change-log.md b/memory-bank/change-log.md
index 40275d09..22cdd5d5 100644
--- a/memory-bank/change-log.md
+++ b/memory-bank/change-log.md
@@ -18,6 +18,43 @@ Follow-ups:
 
 ---
 
+### CL-2026-06-19-ARCHITECTURE-PROGRAMME-MILESTONE: discovery close-out and transition to adoption planning
+
+date: 2026-06-19  
+author: Architecture Review  
+scope: architecture programme  
+type: milestone  
+rationale: Record the conclusion of the architectural discovery programme and the transition into the next architecture phase.  
+impact: Documentation/context only; improves programme clarity, handoff readiness, and next-stream prioritisation; no runtime or implementation behaviour change.  
+status: completed
+
+Summary:
+
+Architectural discovery programme concluded.
+
+Final classifications established:
+
+- Business Decision Models
+- Presentation Models
+- CRM Compatibility Models
+- Workflow / Integration Models
+
+Recommendation:
+
+Transition architecture effort from discovery to adoption planning and API security assessment.
+
+Validation:
+
+- Documentation-only update.
+- No implementation files changed.
+- No tests or lint run because this was a documentation-only milestone entry.
+
+Follow-ups:
+
+- Use Portal API Security & Access Boundary Assessment as the recommended next architecture stream.
+
+---
+
 ### CL-2026-06-18-CRM-CASE-PROGRESS-CONTEXT: record CRM Case Progress Display investigation conclusions
 
 date: 2026-06-18  
diff --git a/memory-bank/debt-list.md b/memory-bank/debt-list.md
index e90c3f22..2f450bfa 100644
--- a/memory-bank/debt-list.md
+++ b/memory-bank/debt-list.md
@@ -81,3 +81,15 @@ Immediate recommended next lane (aligned to architecture Sequence B):
 - Apply broader logging hardening in auth/file/email/account-sensitive paths.
 
 If you want, I can convert this into a sprint-ready debt register (ID, owner, effort, risk reduction, target milestone).
+
+## 6) Additional architecture visibility debt (2026-06-19)
+
+### Security Boundary Visibility
+
+- Inconsistent visibility of endpoint ownership validation.
+- Unknown consistency of authenticated endpoint protection.
+- Incomplete inventory of public vs authenticated endpoints.
+
+Recommended action:
+
+- Perform Portal API Security & Access Boundary Assessment.
diff --git a/memory-bank/open-questions.md b/memory-bank/open-questions.md
index c146c25e..98406c0e 100644
--- a/memory-bank/open-questions.md
+++ b/memory-bank/open-questions.md
@@ -122,3 +122,24 @@ Current context:
     - Householder blocked-message suppression
     - CPO ended-message / deadline consistency
     - missing or conflicting process information handling
+
+---
+
+### Q-005: Portal API Security Boundary Assessment
+
+date: 2026-06-19  
+author: Architect Review  
+scope: API endpoints and ownership enforcement  
+type: question  
+rationale: Discovery programme complete. Security/access boundary review identified as the highest-value architecture stream.  
+impact: security, privacy, maintainability  
+status: open
+
+Question:
+What is the current ownership-validation and access-control posture across public and authenticated API endpoints?
+
+Needed from:
+Architecture review stream
+
+Decision deadline:
+Before major domain-layer adoption or API modernization work.