fix(agents): say which quota stopped a session from starting

crates/buzz-backend-kubernetes/src/sandbox.rs

@@ -841,6 +841,31 @@ fn container_started(pod: &Pod) -> bool {
         })
 }
 
+/// Why the controller has not created the Sandbox's Pod, from its `Ready`
+/// condition. A quota refusal is the usual cause: say which limit is full.
+fn pod_not_created(sandbox: &DynamicObject) -> String {
+    let message = sandbox.data["status"]["conditions"]
+        .as_array()
+        .and_then(|conditions| {
+            conditions
+                .iter()
+                .find(|c| c["type"] == "Ready" && c["status"] != "True")
+        })
+        .and_then(|ready| ready["message"].as_str())
+        .unwrap_or_default();
+    if message.contains("exceeded quota: primary-sessions") {
+        "All of your agent sessions are in use. End an idle session, or wait for one to finish, then retry".into()
+    } else if let Some(quota) = message
+        .split("exceeded quota: ")
+        .nth(1)
+        .and_then(|rest| rest.split(',').next())
+    {
+        format!("Your agent namespace quota `{quota}` is full. End an idle session, or wait for one to finish, then retry")
+    } else {
+        "Sandbox controller has not created its Pod; inspect the Sandbox and retry".into()
+    }
+}
+
 /// Bind credentials to the Sandbox's first Pod and wait for it to start.
 ///
 /// Resumable: a session bound to its first Pod whose Secret is missing and
@@ -873,10 +898,9 @@ async fn bind(
                 ));
             }
             if expired {
-                return Err(
-                    "Sandbox controller has not created its Pod; inspect the Sandbox and retry"
-                        .into(),
-                );
+                // The controller records why it could not create the Pod.
+                let current = session.sandboxes.get_opt(name).await.ok().flatten();
+                return Err(pod_not_created(current.as_ref().unwrap_or(&sandbox)).into());
             }
             tokio::time::sleep(Duration::from_secs(1)).await;
             continue;

crates/buzz-backend-kubernetes/src/sandbox_tests.rs

@@ -1418,3 +1418,36 @@ fn direct_messages_have_one_isolated_workspace_and_owner_gated_conversation_env(
         assert!(parse(invalid).is_err());
     }
 }
+
+#[test]
+fn a_pod_the_quota_refused_names_the_full_limit() {
+    let sandbox = |ready: serde_json::Value| -> DynamicObject {
+        serde_json::from_value(serde_json::json!({
+            "apiVersion": "agents.x-k8s.io/v1alpha1", "kind": "Sandbox",
+            "metadata": {"name": "buzz-agent-a"},
+            "status": {"conditions": [
+                {"type": "Suspended", "status": "False", "message": "Sandbox is not suspended"},
+                ready,
+            ]},
+        }))
+        .unwrap()
+    };
+    // The controller's message from staging.
+    let sessions = sandbox(serde_json::json!({"type": "Ready", "status": "False",
+        "reason": "ReconcilerError",
+        "message": "Error seen: pods \"buzz-agent-a\" is forbidden: exceeded quota: primary-sessions, requested: pods=1, used: pods=5, limited: pods=5"}));
+    assert!(pod_not_created(&sessions).starts_with("All of your agent sessions are in use"));
+    let capacity = sandbox(serde_json::json!({"type": "Ready", "status": "False",
+        "message": "pods \"x\" is forbidden: exceeded quota: agent-capacity, requested: requests.cpu=2"}));
+    assert!(pod_not_created(&capacity).contains("quota `agent-capacity` is full"));
+    for unknown in [
+        sandbox(
+            serde_json::json!({"type": "Ready", "status": "False", "message": "image pull backoff"}),
+        ),
+        sandbox(
+            serde_json::json!({"type": "Ready", "status": "True", "message": "exceeded quota: primary-sessions"}),
+        ),
+    ] {
+        assert!(pod_not_created(&unknown).starts_with("Sandbox controller has not created its Pod"));
+    }
+}