[codex-analytics] feature plumbing and emittance (#16640)

---
[//]: # (BEGIN SAPLING FOOTER)
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with [ReviewStack](https://reviewstack.dev/openai/codex/pull/16640).
* #16870
* #16706
* #16641
* __->__ #16640

codex-rs/app-server/tests/suite/v2/turn_start.rs

@@ -1,4 +1,5 @@
 use anyhow::Result;
+use app_test_support::DEFAULT_CLIENT_NAME;
 use app_test_support::McpProcess;
 use app_test_support::create_apply_patch_sse_response;
 use app_test_support::create_exec_command_sse_response;
@@ -9,6 +10,7 @@ use app_test_support::create_mock_responses_server_sequence_unchecked;
 use app_test_support::create_shell_command_sse_response;
 use app_test_support::format_with_current_shell_display;
 use app_test_support::to_response;
+use app_test_support::write_mock_responses_config_toml_with_chatgpt_base_url;
 use codex_app_server::INPUT_TOO_LARGE_ERROR_CODE;
 use codex_app_server::INVALID_PARAMS_ERROR_CODE;
 use codex_app_server_protocol::ByteRange;
@@ -64,6 +66,10 @@ use std::path::Path;
 use tempfile::TempDir;
 use tokio::time::timeout;
 
+use super::analytics::enable_analytics_capture;
+use super::analytics::mount_analytics_capture;
+use super::analytics::wait_for_analytics_event;
+
 #[cfg(windows)]
 const DEFAULT_READ_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(25);
 #[cfg(not(windows))]
@@ -328,6 +334,163 @@ async fn thread_start_omits_empty_instruction_overrides_from_model_request() ->
     Ok(())
 }
 
+#[tokio::test]
+async fn turn_start_tracks_turn_event_analytics() -> Result<()> {
+    let responses = vec![create_final_assistant_message_sse_response("Done")?];
+    let server = create_mock_responses_server_sequence_unchecked(responses).await;
+
+    let codex_home = TempDir::new()?;
+    write_mock_responses_config_toml_with_chatgpt_base_url(
+        codex_home.path(),
+        &server.uri(),
+        &server.uri(),
+    )?;
+    enable_analytics_capture(&server, codex_home.path()).await?;
+
+    let mut mcp = McpProcess::new_without_managed_config(codex_home.path()).await?;
+    timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
+
+    let thread_req = mcp
+        .send_thread_start_request(ThreadStartParams {
+            model: Some("mock-model".to_string()),
+            ..Default::default()
+        })
+        .await?;
+    let thread_resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(thread_req)),
+    )
+    .await??;
+    let ThreadStartResponse { thread, .. } = to_response::<ThreadStartResponse>(thread_resp)?;
+
+    let turn_req = mcp
+        .send_turn_start_request(TurnStartParams {
+            thread_id: thread.id.clone(),
+            input: vec![V2UserInput::Image {
+                url: "https://example.com/a.png".to_string(),
+            }],
+            ..Default::default()
+        })
+        .await?;
+    let turn_resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(turn_req)),
+    )
+    .await??;
+    let TurnStartResponse { turn } = to_response::<TurnStartResponse>(turn_resp)?;
+
+    timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_notification_message("turn/completed"),
+    )
+    .await??;
+
+    let event = wait_for_analytics_event(&server, DEFAULT_READ_TIMEOUT, "codex_turn_event").await?;
+    assert_eq!(event["event_params"]["thread_id"], thread.id);
+    assert_eq!(event["event_params"]["turn_id"], turn.id);
+    assert_eq!(
+        event["event_params"]["app_server_client"]["product_client_id"],
+        DEFAULT_CLIENT_NAME
+    );
+    assert_eq!(event["event_params"]["model"], "mock-model");
+    assert_eq!(event["event_params"]["model_provider"], "mock_provider");
+    assert_eq!(event["event_params"]["sandbox_policy"], "read_only");
+    assert_eq!(event["event_params"]["ephemeral"], false);
+    assert_eq!(event["event_params"]["thread_source"], "user");
+    assert_eq!(event["event_params"]["initialization_mode"], "new");
+    assert_eq!(
+        event["event_params"]["subagent_source"],
+        serde_json::Value::Null
+    );
+    assert_eq!(
+        event["event_params"]["parent_thread_id"],
+        serde_json::Value::Null
+    );
+    assert_eq!(event["event_params"]["num_input_images"], 1);
+    assert_eq!(event["event_params"]["status"], "completed");
+    assert!(event["event_params"]["started_at"].as_u64().is_some());
+    assert!(event["event_params"]["completed_at"].as_u64().is_some());
+    assert!(event["event_params"]["duration_ms"].as_u64().is_some());
+    assert_eq!(event["event_params"]["input_tokens"], 0);
+    assert_eq!(event["event_params"]["cached_input_tokens"], 0);
+    assert_eq!(event["event_params"]["output_tokens"], 0);
+    assert_eq!(event["event_params"]["reasoning_output_tokens"], 0);
+    assert_eq!(event["event_params"]["total_tokens"], 0);
+
+    Ok(())
+}
+
+#[tokio::test]
+async fn turn_start_does_not_track_turn_event_analytics_without_feature() -> Result<()> {
+    let responses = vec![create_final_assistant_message_sse_response("Done")?];
+    let server = create_mock_responses_server_sequence_unchecked(responses).await;
+
+    let codex_home = TempDir::new()?;
+    write_mock_responses_config_toml_with_chatgpt_base_url(
+        codex_home.path(),
+        &server.uri(),
+        &server.uri(),
+    )?;
+    let config_path = codex_home.path().join("config.toml");
+    let config_toml = std::fs::read_to_string(&config_path)?;
+    std::fs::write(
+        &config_path,
+        format!("{config_toml}\n[features]\ngeneral_analytics = false\n"),
+    )?;
+    mount_analytics_capture(&server, codex_home.path()).await?;
+
+    let mut mcp = McpProcess::new_without_managed_config(codex_home.path()).await?;
+    timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
+
+    let thread_req = mcp
+        .send_thread_start_request(ThreadStartParams {
+            model: Some("mock-model".to_string()),
+            ..Default::default()
+        })
+        .await?;
+    let thread_resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(thread_req)),
+    )
+    .await??;
+    let ThreadStartResponse { thread, .. } = to_response::<ThreadStartResponse>(thread_resp)?;
+
+    let turn_req = mcp
+        .send_turn_start_request(TurnStartParams {
+            thread_id: thread.id,
+            input: vec![V2UserInput::Text {
+                text: "hello".to_string(),
+                text_elements: Vec::new(),
+            }],
+            ..Default::default()
+        })
+        .await?;
+    let turn_resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(turn_req)),
+    )
+    .await??;
+    let _ = to_response::<TurnStartResponse>(turn_resp)?;
+
+    timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_notification_message("turn/completed"),
+    )
+    .await??;
+
+    let turn_event = wait_for_analytics_event(
+        &server,
+        std::time::Duration::from_millis(250),
+        "codex_turn_event",
+    )
+    .await;
+    assert!(
+        turn_event.is_err(),
+        "turn analytics should be gated off when general_analytics is disabled"
+    );
+    Ok(())
+}
+
 #[tokio::test]
 async fn turn_start_accepts_text_at_limit_with_mention_item() -> Result<()> {
     let responses = vec![create_final_assistant_message_sse_response("Done")?];