diff --git a/server/src/__tests__/openapi-routes.test.ts b/server/src/__tests__/openapi-routes.test.ts
index 3500aa68f94..a762b955064 100644
--- a/server/src/__tests__/openapi-routes.test.ts
+++ b/server/src/__tests__/openapi-routes.test.ts
@@ -576,6 +576,16 @@ describe("openapi routes", () => {
     expect(dismiss.description).toContain("viewers may dismiss their own");
   });
 
+  it("tells agents that Agent Chat is always on instead of advertising a retired toggle", async () => {
+    const res = await request(createApp()).get("/api/openapi.json");
+    const experimental = res.body.paths["/api/instance/settings/experimental"];
+    for (const operation of [experimental.get, experimental.patch]) {
+      expect(operation.description).toContain("Agent Chat is always on");
+      expect(operation.description).toContain("enableAgentChat is a retired compatibility key");
+      expect(operation.description).toContain("tell them it is already on");
+    }
+  });
+
   it("tells agents that archiving keeps a status card and where a person restores it", async () => {
     const res = await request(createApp()).get("/api/openapi.json");
     const patch = res.body.paths["/api/status-cards/{id}"].patch;
diff --git a/server/src/routes/openapi.ts b/server/src/routes/openapi.ts
index 5efd8ba619b..a158743c1e7 100644
--- a/server/src/routes/openapi.ts
+++ b/server/src/routes/openapi.ts
@@ -7120,6 +7120,7 @@ registry.registerPath({
   path: "/api/instance/settings/experimental",
   tags: ["instance"],
   summary: "Get experimental instance settings",
+  description: "Agent Chat is always on for every person on every instance and needs no setup. enableAgentChat is a retired compatibility key: it always reads true and written values are ignored. If someone asks to enable Agent Chat, tell them it is already on, since they are using it now; do not send them to a settings toggle.",
   responses: { 200: r.ok(), 401: r.unauthorized },
 });
 
@@ -7128,7 +7129,7 @@ registry.registerPath({
   path: "/api/instance/settings/experimental",
   tags: ["instance"],
   summary: "Update experimental instance settings",
-  description: "Requires instance-admin access or a trusted Cloud stack admin. Operator-hidden settings and Cloud-managed feature restrictions still apply. This does not grant access to other instance administration operations.",
+  description: "Requires instance-admin access or a trusted Cloud stack admin. Operator-hidden settings and Cloud-managed feature restrictions still apply. This does not grant access to other instance administration operations. Agent Chat is always on for every person on every instance and needs no setup. enableAgentChat is a retired compatibility key: it always reads true and written values are ignored. If someone asks to enable Agent Chat, tell them it is already on, since they are using it now; do not send them to a settings toggle.",
   request: { body: jsonBody(patchInstanceExperimentalSettingsSchema) },
   responses: { 200: r.ok(), 400: r.badRequest, 401: r.unauthorized, 403: r.forbidden },
 });