diff --git a/features/a2a_facade_coverage.feature b/features/a2a_facade_coverage.feature
index eaee174d2..a8acf2b5d 100644
--- a/features/a2a_facade_coverage.feature
+++ b/features/a2a_facade_coverage.feature
@@ -19,11 +19,15 @@ Feature: A2A local facade coverage — uncovered handler and edge-case paths
     Then the facade-cov response status should be "ok"
     And the facade-cov response data key "status" should equal "closed"
 
-  Scenario: Session close with empty session_id and no service
+  Scenario: Session close with empty session_id and no service raises ValueError error
     Given a facade-cov facade with no services
     When I dispatch facade-cov operation "session.close" with params {"session_id": ""}
-    Then the facade-cov response status should be "ok"
-    And the facade-cov response data key "status" should equal "closed"
+    Then the facade-cov response status should be "error"
+
+  Scenario: Session close with missing session_id key and no service raises ValueError error
+    Given a facade-cov facade with no services
+    When I dispatch facade-cov operation "session.close" with params {}
+    Then the facade-cov response status should be "error"
 
   # -------------------------------------------------------------------
   # Plan cancel — with service wired (lines 501-502)
diff --git a/src/cleveragents/a2a/facade.py b/src/cleveragents/a2a/facade.py
index 43be9f4c2..4d0e477f5 100644
--- a/src/cleveragents/a2a/facade.py
+++ b/src/cleveragents/a2a/facade.py
@@ -354,6 +354,12 @@ class A2aLocalFacade:
     def _handle_session_close(self, params: dict[str, Any]) -> dict[str, Any]:
         session_id = params.get("session_id", "")
 
+        # Validate session_id BEFORE checking service availability so that
+        # empty or missing IDs are never silently passed through to
+        # devcontainer cleanup regardless of whether SessionService is wired.
+        if not session_id:
+            raise ValueError("session_id is required")
+
         svc = self._session_service
         if svc is None:
             # R7-F4 fix: still run container cleanup even without a
@@ -361,8 +367,6 @@ class A2aLocalFacade:
             self._cleanup_session_devcontainers(session_id)
             return {"status": "closed"}
 
-        if not session_id:
-            raise ValueError("session_id is required")
         svc.delete(session_id)
 
         # R7-F4 fix: run container cleanup after session deletion.