diff --git a/src/server.ts b/src/server.ts
index d5f5d47..6963f54 100644
--- a/src/server.ts
+++ b/src/server.ts
@@ -72,7 +72,10 @@ async function authorizeSamChat(
   } catch {
     return new Response("Unauthorized", { status: 401 });
   }
-  const session = await SamSessionRepository.getActiveSession(sessionId);
+  const session = await SamSessionRepository.getActiveSession(
+    sessionId,
+    context.userId,
+  );
   const project = session
     ? await ProjectRepository.getProjectForOrganization(
         session.projectId,
diff --git a/src/server/features/sam/SamSessionRepository.ts b/src/server/features/sam/SamSessionRepository.ts
index 9430c92..15e5e74 100644
--- a/src/server/features/sam/SamSessionRepository.ts
+++ b/src/server/features/sam/SamSessionRepository.ts
@@ -21,7 +21,8 @@ async function createSession(input: CreateSamSessionInput) {
 }
 
 // Callers must have already authorized the project (requireProjectContext).
-async function listSessionsForProject(projectId: string) {
+// Scoped to userId so a project member only sees their own sessions.
+async function listSessionsForProject(projectId: string, userId: string) {
   return db
     .select({
       id: samSessions.id,
@@ -31,7 +32,11 @@ async function listSessionsForProject(projectId: string) {
     })
     .from(samSessions)
     .where(
-      and(eq(samSessions.projectId, projectId), isNull(samSessions.archivedAt)),
+      and(
+        eq(samSessions.projectId, projectId),
+        eq(samSessions.userId, userId),
+        isNull(samSessions.archivedAt),
+      ),
     )
     .orderBy(desc(samSessions.updatedAt), desc(samSessions.id));
 }
@@ -49,16 +54,23 @@ async function getSessionById(id: string) {
   return row ?? null;
 }
 
-// Excludes archived sessions so callers treat them like deleted ones
-// (connection refused / not archivable) even though the row and DO transcript
-// are kept. Does NOT authorize: callers must check the caller's access to
+// Look up a caller's own active session by id, scoped to userId so one org
+// member can't act on another's session. Excludes archived sessions so callers
+// treat them like deleted ones (connection refused / not archivable) even
+// though the row and DO transcript are kept. Callers must still check access to
 // row.projectId via the canonical project-access path
 // (ProjectRepository.getProjectForOrganization) before acting on the session.
-async function getActiveSession(id: string) {
+async function getActiveSession(id: string, userId: string) {
   const [row] = await db
     .select()
     .from(samSessions)
-    .where(and(eq(samSessions.id, id), isNull(samSessions.archivedAt)))
+    .where(
+      and(
+        eq(samSessions.id, id),
+        eq(samSessions.userId, userId),
+        isNull(samSessions.archivedAt),
+      ),
+    )
     .limit(1);
   return row ?? null;
 }
diff --git a/src/serverFunctions/sam.ts b/src/serverFunctions/sam.ts
index f263df0..ebe22d0 100644
--- a/src/serverFunctions/sam.ts
+++ b/src/serverFunctions/sam.ts
@@ -17,7 +17,10 @@ export const listSamSessions = createServerFn({ method: "GET" })
   .middleware(requireProjectContext)
   .inputValidator((data: unknown) => projectScopedSchema.parse(data))
   .handler(async ({ context }) => {
-    return SamSessionRepository.listSessionsForProject(context.projectId);
+    return SamSessionRepository.listSessionsForProject(
+      context.projectId,
+      context.userId,
+    );
   });
 
 // Creates a new SAM chat session and returns its id; the client then opens a DO
@@ -47,7 +50,10 @@ export const archiveSamSession = createServerFn({ method: "POST" })
   .handler(async ({ data, context }) => {
     // Authorize against the session's project (the canonical project-access
     // path), not the caller's org directly.
-    const session = await SamSessionRepository.getActiveSession(data.sessionId);
+    const session = await SamSessionRepository.getActiveSession(
+      data.sessionId,
+      context.userId,
+    );
     const project = session
       ? await ProjectRepository.getProjectForOrganization(
           session.projectId,