diff --git a/codex-rs/mcp-server/tests/codex_tool.rs b/codex-rs/mcp-server/tests/codex_tool.rs
index 92f11eaa4f..ead8adb2a8 100644
--- a/codex-rs/mcp-server/tests/codex_tool.rs
+++ b/codex-rs/mcp-server/tests/codex_tool.rs
@@ -114,6 +114,13 @@ async fn shell_command_approval_triggers_elicitation() -> anyhow::Result<()> {
         )
         .await?;
 
+    // Verify task_complete notification arrives before the tool call completes.
+    let _task_complete = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp_process.read_stream_until_legacy_task_complete_notification(),
+    )
+    .await??;
+
     // Verify the original `codex` tool call completes and that `git init` ran
     // successfully.
     let codex_response = timeout(
diff --git a/codex-rs/mcp-server/tests/common/mcp_process.rs b/codex-rs/mcp-server/tests/common/mcp_process.rs
index a659b1d950..35484264fa 100644
--- a/codex-rs/mcp-server/tests/common/mcp_process.rs
+++ b/codex-rs/mcp-server/tests/common/mcp_process.rs
@@ -474,4 +474,46 @@ impl McpProcess {
         }))
         .await
     }
+
+    /// Reads notifications until a legacy TaskComplete event is observed:
+    /// Method "codex/event" with params.msg.type == "task_complete".
+    pub async fn read_stream_until_legacy_task_complete_notification(
+        &mut self,
+    ) -> anyhow::Result<JSONRPCNotification> {
+        loop {
+            let message = self.read_jsonrpc_message().await?;
+            eprint!("message: {message:?}");
+
+            match message {
+                JSONRPCMessage::Notification(notification) => {
+                    let is_match = if notification.method == "codex/event" {
+                        if let Some(params) = &notification.params {
+                            params
+                                .get("msg")
+                                .and_then(|m| m.get("type"))
+                                .and_then(|t| t.as_str())
+                                == Some("task_complete")
+                        } else {
+                            false
+                        }
+                    } else {
+                        false
+                    };
+
+                    if is_match {
+                        return Ok(notification);
+                    }
+                }
+                JSONRPCMessage::Request(_) => {
+                    anyhow::bail!("unexpected JSONRPCMessage::Request: {message:?}");
+                }
+                JSONRPCMessage::Error(_) => {
+                    anyhow::bail!("unexpected JSONRPCMessage::Error: {message:?}");
+                }
+                JSONRPCMessage::Response(_) => {
+                    anyhow::bail!("unexpected JSONRPCMessage::Response: {message:?}");
+                }
+            }
+        }
+    }
 }