diff --git a/apps/mcp/src/server/auth/rbac.test.ts b/apps/mcp/src/server/auth/rbac.test.ts
index bbb0143d..b75bfb70 100644
--- a/apps/mcp/src/server/auth/rbac.test.ts
+++ b/apps/mcp/src/server/auth/rbac.test.ts
@@ -46,4 +46,16 @@ describe("effectiveContainerTagAccess", () => {
 			{ containerTag: "one", permission: "read" },
 		])
 	})
+
+	it("treats full-scope read-only grants as read on every tag", () => {
+		const session: SessionInfo = {
+			...baseSession,
+			scope: { type: "full", permission: "read" },
+		}
+
+		expect(effectiveContainerTagAccess(["one", "two"], session)).toEqual([
+			{ containerTag: "one", permission: "read" },
+			{ containerTag: "two", permission: "read" },
+		])
+	})
 })
diff --git a/apps/mcp/src/server/auth/rbac.ts b/apps/mcp/src/server/auth/rbac.ts
index 327587a2..bc1198af 100644
--- a/apps/mcp/src/server/auth/rbac.ts
+++ b/apps/mcp/src/server/auth/rbac.ts
@@ -21,10 +21,12 @@ export function effectiveContainerTagAccess(
 			permission = memberAccess.get(containerTag) ?? "read"
 		}
 
-		if (
+		if (session.scope?.permission === "read") {
+			permission = "read"
+		} else if (
 			session.scope?.type === "scoped" &&
-			(session.scope.permission === "read" ||
-				(scopedTags.size > 0 && !scopedTags.has(containerTag)))
+			scopedTags.size > 0 &&
+			!scopedTags.has(containerTag)
 		) {
 			permission = "read"
 		}