fix: forward originator to Codex Apps MCP (#31481)

## Summary
- Forward Codexs canonical `originator` header on ChatGPT-hosted Apps
and plugin-runtime MCP requests.
- Preserve the configured `X-OpenAI-Product-Sku` header.
- Cover originator-only and originator-plus-SKU configurations.

## Why
Sites project creation is logged downstream of Apps MCP. Production
validation found `CODEX_UNKNOWN_DEFAULT` project-created threads that
matched `codex_surface=desktop_app` and `originator=Codex Desktop` in
`fact_codex_cli`
([query](https://kepler.gateway.data-1.internal.api.openai.org/permalink/H_mVoVPqLQ0)).

The hosted Apps MCP configuration forwarded the product SKU but not
Codexs canonical originator, so codex-backend could not derive
`CODEX_DESKTOP_APP` for those tool calls.

## Validation
- `just fmt`
- `CARGO_HOME=/private/tmp/codex-cargo-home
CARGO_TARGET_DIR=/private/tmp/codex-target just test -p codex-mcp` (106
passed)
- `CARGO_HOME=/private/tmp/codex-cargo-home
CARGO_TARGET_DIR=/private/tmp/codex-target just fix -p codex-mcp`

codex-rs/codex-mcp/src/connection_manager_tests.rs

@@ -1418,6 +1418,7 @@ fn server_metadata_preserves_tool_approval_policy() {
     let mut config = crate::codex_apps_mcp_server_config(
         "https://docs.example",
         /*apps_mcp_product_sku*/ None,
+        /*originator*/ None,
     );
     config.environment_id = "remote".to_string();
     config.default_tools_approval_mode = Some(AppToolApproval::Prompt);
@@ -1462,6 +1463,7 @@ fn host_owned_codex_apps_matches_reserved_name_with_server_metadata() {
     let server = EffectiveMcpServer::configured(crate::codex_apps_mcp_server_config(
         "https://chatgpt.com",
         /*apps_mcp_product_sku*/ None,
+        /*originator*/ None,
     ));
     manager.server_metadata.insert(
         CODEX_APPS_MCP_SERVER_NAME.to_string(),

codex-rs/codex-mcp/src/mcp/mod.rs

@@ -493,10 +493,12 @@ fn codex_apps_mcp_url_for_base_url(base_url: &str) -> String {
 pub fn codex_apps_mcp_server_config(
     chatgpt_base_url: &str,
     apps_mcp_product_sku: Option<&str>,
+    originator: Option<&str>,
 ) -> McpServerConfig {
     mcp_server_config_for_url(
         codex_apps_mcp_url_for_base_url(chatgpt_base_url),
         apps_mcp_product_sku,
+        originator,
         McpServerAuth::ChatGpt,
     )
 }
@@ -505,6 +507,7 @@ pub fn codex_apps_mcp_server_config(
 pub fn hosted_plugin_runtime_mcp_server_config(
     chatgpt_base_url: &str,
     apps_mcp_product_sku: Option<&str>,
+    originator: Option<&str>,
 ) -> McpServerConfig {
     let base_url = normalize_codex_apps_base_url(chatgpt_base_url);
     let base_url = if base_url.contains("/backend-api") || base_url.contains("/api/codex") {
@@ -515,6 +518,7 @@ pub fn hosted_plugin_runtime_mcp_server_config(
     mcp_server_config_for_url(
         format!("{base_url}/ps/mcp"),
         apps_mcp_product_sku,
+        originator,
         McpServerAuth::ChatGpt,
     )
 }
@@ -522,19 +526,21 @@ pub fn hosted_plugin_runtime_mcp_server_config(
 fn mcp_server_config_for_url(
     url: String,
     apps_mcp_product_sku: Option<&str>,
+    originator: Option<&str>,
     auth_mode: McpServerAuth,
 ) -> McpServerConfig {
     let product_sku = apps_mcp_product_sku.unwrap_or(DEFAULT_CODEX_APPS_MCP_PRODUCT_SKU);
-    let http_headers = Some(HashMap::from([(
-        "X-OpenAI-Product-Sku".to_string(),
-        product_sku.to_string(),
-    )]));
+    let mut http_headers =
+        HashMap::from([("X-OpenAI-Product-Sku".to_string(), product_sku.to_string())]);
+    if let Some(originator) = originator {
+        http_headers.insert("originator".to_string(), originator.to_string());
+    }
 
     McpServerConfig {
         transport: McpServerTransportConfig::StreamableHttp {
             url,
             bearer_token_env_var: codex_apps_mcp_bearer_token_env_var(),
-            http_headers,
+            http_headers: Some(http_headers),
             env_http_headers: None,
         },
         auth: auth_mode,

codex-rs/codex-mcp/src/mcp/mod_tests.rs

@@ -130,7 +130,11 @@ fn tool_plugin_provenance_collects_app_and_mcp_sources() {
         "alpha".to_string(),
         McpPluginAttribution::new("alpha@test".to_string(), "alpha-plugin".to_string()),
         /*plugin_order*/ 0,
-        codex_apps_mcp_server_config("https://alpha.example", /*apps_mcp_product_sku*/ None),
+        codex_apps_mcp_server_config(
+            "https://alpha.example",
+            /*apps_mcp_product_sku*/ None,
+            /*originator*/ None,
+        ),
     ));
     config.mcp_server_catalog = catalog.build();
     config.connector_snapshot =
@@ -197,7 +201,11 @@ fn selected_mcp_attribution_does_not_join_an_unrelated_local_summary() {
             "Executor GitHub".to_string(),
         ),
         /*selection_order*/ 0,
-        codex_apps_mcp_server_config("https://github.example", /*apps_mcp_product_sku*/ None),
+        codex_apps_mcp_server_config(
+            "https://github.example",
+            /*apps_mcp_product_sku*/ None,
+            /*originator*/ None,
+        ),
     ));
     config.mcp_server_catalog = catalog.build();
     config.connector_snapshot =
@@ -252,8 +260,11 @@ fn codex_apps_mcp_url_for_base_url_keeps_existing_paths() {
 
 #[test]
 fn codex_apps_server_config_uses_legacy_codex_apps_path() {
-    let config =
-        codex_apps_mcp_server_config("https://chatgpt.com", /*apps_mcp_product_sku*/ None);
+    let config = codex_apps_mcp_server_config(
+        "https://chatgpt.com",
+        /*apps_mcp_product_sku*/ None,
+        /*originator*/ None,
+    );
     let url = match &config.transport {
         McpServerTransportConfig::StreamableHttp { url, .. } => url,
         _ => panic!("expected streamable http transport for codex apps"),
@@ -262,10 +273,41 @@ fn codex_apps_server_config_uses_legacy_codex_apps_path() {
     assert_eq!(url, "https://chatgpt.com/backend-api/wham/apps");
 }
 
+#[test]
+fn codex_apps_server_config_forwards_thread_originator_header() {
+    let config = codex_apps_mcp_server_config(
+        "https://chatgpt.com",
+        /*apps_mcp_product_sku*/ None,
+        Some("thread_originator"),
+    );
+
+    match &config.transport {
+        McpServerTransportConfig::StreamableHttp {
+            http_headers,
+            env_http_headers,
+            ..
+        } => {
+            assert_eq!(
+                http_headers,
+                &Some(HashMap::from([
+                    ("originator".to_string(), "thread_originator".to_string()),
+                    ("X-OpenAI-Product-Sku".to_string(), "codex".to_string()),
+                ]))
+            );
+            assert!(env_http_headers.is_none());
+        }
+        other => panic!("expected streamable http transport, got {other:?}"),
+    }
+}
+
 #[test]
 fn codex_apps_server_config_sets_product_sku_header() {
     for (configured_product_sku, expected_product_sku) in [(None, "codex"), (Some("tpp"), "tpp")] {
-        let config = codex_apps_mcp_server_config("https://chatgpt.com", configured_product_sku);
+        let config = codex_apps_mcp_server_config(
+            "https://chatgpt.com",
+            configured_product_sku,
+            /*originator*/ None,
+        );
 
         match &config.transport {
             McpServerTransportConfig::StreamableHttp {
@@ -287,6 +329,33 @@ fn codex_apps_server_config_sets_product_sku_header() {
     }
 }
 
+#[test]
+fn codex_apps_server_config_forwards_originator_and_configured_product_sku_headers() {
+    let config = codex_apps_mcp_server_config(
+        "https://chatgpt.com",
+        Some("tpp"),
+        Some("thread_originator"),
+    );
+
+    match &config.transport {
+        McpServerTransportConfig::StreamableHttp {
+            http_headers,
+            env_http_headers,
+            ..
+        } => {
+            assert_eq!(
+                http_headers,
+                &Some(HashMap::from([
+                    ("originator".to_string(), "thread_originator".to_string()),
+                    ("X-OpenAI-Product-Sku".to_string(), "tpp".to_string()),
+                ]))
+            );
+            assert!(env_http_headers.is_none());
+        }
+        other => panic!("expected streamable http transport, got {other:?}"),
+    }
+}
+
 #[tokio::test]
 async fn effective_mcp_servers_preserve_runtime_servers() {
     let codex_home = tempfile::tempdir().expect("tempdir");
@@ -352,6 +421,7 @@ async fn effective_mcp_servers_preserve_runtime_servers() {
         codex_apps_mcp_server_config(
             &config.chatgpt_base_url,
             config.apps_mcp_product_sku.as_deref(),
+            /*originator*/ None,
         ),
     ));
     config.mcp_server_catalog = catalog.build();

codex-rs/core/src/mcp.rs

@@ -79,9 +79,15 @@ impl McpManager {
     /// Returns the MCP config after applying compatibility built-ins and
     /// runtime-only extension overlays.
     pub async fn runtime_config(&self, config: &Config) -> McpConfig {
-        self.runtime_config_with_context(McpServerContributionContext::global(config))
-            .await
-            .config
+        self.runtime_config_with_context(
+            McpServerContributionContext::global(config),
+            // Threadless discovery and control-plane paths have no effective thread
+            // originator; active-thread tool calls use runtime_config_for_step below.
+            /*originator*/
+            None,
+        )
+        .await
+        .config
     }
 
     pub(crate) async fn runtime_config_for_step(
@@ -89,20 +95,26 @@ impl McpManager {
         config: &Config,
         thread_init: &ExtensionDataInit,
         thread_store: &ExtensionData,
+        originator: &str,
         available_environment_ids: &[String],
     ) -> McpRuntimeProjection {
-        self.runtime_config_with_context(McpServerContributionContext::for_step(
-            config,
-            thread_init,
-            thread_store,
-            available_environment_ids,
-        ))
+        self.runtime_config_with_context(
+            McpServerContributionContext::for_step(
+                config,
+                thread_init,
+                thread_store,
+                originator,
+                available_environment_ids,
+            ),
+            Some(originator),
+        )
         .await
     }
 
     async fn runtime_config_with_context(
         &self,
         context: McpServerContributionContext<'_, Config>,
+        originator: Option<&str>,
     ) -> McpRuntimeProjection {
         let config = context.config();
         let mut selected_plugin_available = false;
@@ -181,6 +193,7 @@ impl McpManager {
                 codex_apps_mcp_server_config(
                     &mcp_config.chatgpt_base_url,
                     mcp_config.apps_mcp_product_sku.as_deref(),
+                    originator,
                 ),
             ));
         } else {

codex-rs/core/src/mcp_tool_call_tests.rs

@@ -1435,6 +1435,7 @@ async fn host_owned_codex_apps_manager(
         codex_mcp::EffectiveMcpServer::configured(codex_mcp::codex_apps_mcp_server_config(
             "https://chatgpt.com",
             /*apps_mcp_product_sku*/ None,
+            Some(&turn_context.originator),
         )),
     )]);
     let manager = codex_mcp::McpConnectionManager::new(

codex-rs/core/src/session/mcp.rs

@@ -78,6 +78,7 @@ impl ElicitationReviewer for GuardianMcpElicitationReviewer {
 
 impl Session {
     pub(crate) async fn runtime_mcp_config(&self, config: &Config) -> McpConfig {
+        let originator = self.originator().await;
         let environments = self.services.turn_environments.snapshot().await;
         let selected_capability_roots = self
             .resolve_selected_capability_roots_for_step(&environments)
@@ -90,6 +91,7 @@ impl Session {
                 config,
                 &self.services.mcp_thread_init,
                 &self.services.thread_extension_data,
+                &originator,
                 &available_environment_ids,
             )
             .await
@@ -132,6 +134,7 @@ impl Session {
                 &turn_context.config,
                 &self.services.mcp_thread_init,
                 &self.services.thread_extension_data,
+                &turn_context.originator,
                 &available_environment_ids,
             )
             .await;
@@ -475,6 +478,7 @@ impl Session {
                 &refresh_config,
                 &self.services.mcp_thread_init,
                 &self.services.thread_extension_data,
+                &turn_context.originator,
                 &available_environment_ids,
             )
             .await;
@@ -543,6 +547,7 @@ impl Session {
                 refresh_config,
                 &self.services.mcp_thread_init,
                 &self.services.thread_extension_data,
+                &turn_context.originator,
                 &available_environment_ids,
             )
             .await;

codex-rs/core/src/session/session.rs

@@ -672,6 +672,7 @@ impl Session {
         let mcp_manager_for_mcp = Arc::clone(&mcp_manager);
         let mcp_thread_init_for_startup = &mcp_thread_init;
         let thread_extension_data_for_mcp = &thread_extension_data;
+        let mcp_originator = session_configuration.originator.clone();
         let mcp_runtime_cwd = session_configuration
             .environment_selections()
             .first()
@@ -688,6 +689,7 @@ impl Session {
                     &config_for_mcp,
                     mcp_thread_init_for_startup,
                     thread_extension_data_for_mcp,
+                    &mcp_originator,
                     /*available_environment_ids*/ &[],
                 )
                 .await;

codex-rs/core/src/thread_manager_tests.rs

@@ -553,6 +553,7 @@ async fn start_thread_seeds_extension_data_for_mcp_and_lifecycle_contributors()
                 let mut server = codex_mcp::codex_apps_mcp_server_config(
                     "https://selected.invalid",
                     /*apps_mcp_product_sku*/ None,
+                    /*originator*/ None,
                 );
                 let CapabilityRootLocation::Environment { environment_id, .. } =
                     &selected_root.location;
@@ -574,6 +575,10 @@ async fn start_thread_seeds_extension_data_for_mcp_and_lifecycle_contributors()
     let mut config = test_config().await;
     config.codex_home = temp_dir.path().join("codex-home").abs();
     config.cwd = config.codex_home.abs();
+    config
+        .features
+        .enable(Feature::Apps)
+        .expect("test config should allow apps");
     std::fs::create_dir_all(&config.codex_home).expect("create codex home");
 
     let lifecycle_observed = Arc::new(std::sync::Mutex::new(Vec::new()));
@@ -620,7 +625,7 @@ async fn start_thread_seeds_extension_data_for_mcp_and_lifecycle_contributors()
             session_source: None,
             thread_source: None,
             dynamic_tools: Vec::new(),
-            metrics_service_name: None,
+            metrics_service_name: Some("codex_work_desktop".to_string()),
             parent_trace: None,
             environments: Vec::new(),
             thread_extension_init: selected_root_init("selected-a", "env-a"),
@@ -646,6 +651,7 @@ async fn start_thread_seeds_extension_data_for_mcp_and_lifecycle_contributors()
         .await
         .expect("start second thread");
     let first_session = &first_thread.thread.codex.session;
+    let first_originator = first_session.originator().await;
     let first_resolved = first_session
         .services
         .mcp_manager
@@ -653,10 +659,12 @@ async fn start_thread_seeds_extension_data_for_mcp_and_lifecycle_contributors()
             &config,
             &first_session.services.mcp_thread_init,
             &first_session.services.thread_extension_data,
+            &first_originator,
             /*available_environment_ids*/ &[],
         )
         .await;
     let second_session = &second_thread.thread.codex.session;
+    let second_originator = second_session.originator().await;
     let second_resolved = second_session
         .services
         .mcp_manager
@@ -664,6 +672,7 @@ async fn start_thread_seeds_extension_data_for_mcp_and_lifecycle_contributors()
             &config,
             &second_session.services.mcp_thread_init,
             &second_session.services.thread_extension_data,
+            &second_originator,
             /*available_environment_ids*/ &[],
         )
         .await;
@@ -706,6 +715,21 @@ async fn start_thread_seeds_extension_data_for_mcp_and_lifecycle_contributors()
         selected_servers(&second_resolved.config),
         std::collections::BTreeMap::from([("selected-b".to_string(), "env-b".to_string())])
     );
+    let codex_apps_server = codex_mcp::configured_mcp_servers(&first_resolved.config)
+        .remove(codex_mcp::CODEX_APPS_MCP_SERVER_NAME)
+        .expect("Codex Apps server should be configured");
+    let codex_apps_headers = match codex_apps_server.transport {
+        codex_config::McpServerTransportConfig::StreamableHttp { http_headers, .. } => http_headers,
+        codex_config::McpServerTransportConfig::Stdio { .. } => {
+            panic!("Codex Apps server should use streamable HTTP")
+        }
+    };
+    assert_eq!(
+        codex_apps_headers
+            .expect("Codex Apps headers should be configured")
+            .get("originator"),
+        Some(&"codex_work_desktop".to_string())
+    );
 }
 
 #[tokio::test]

codex-rs/core/tests/suite/mcp_auth_refresh.rs

@@ -66,6 +66,7 @@ async fn hosted_plugin_runtime_ps_mcp_tool_calls_use_current_auth_manager_token(
     let mut hosted_plugin_runtime_config = codex_mcp::hosted_plugin_runtime_mcp_server_config(
         &apps_server.chatgpt_base_url,
         /*apps_mcp_product_sku*/ None,
+        /*originator*/ None,
     );
     let McpServerTransportConfig::StreamableHttp {
         bearer_token_env_var,

codex-rs/ext/extension-api/src/contributors/mcp.rs

@@ -15,6 +15,8 @@ pub struct McpServerContributionContext<'a, C> {
     thread_store: Option<&'a ExtensionData>,
     /// Stable host inputs for the active thread, when resolution is thread-scoped.
     thread_init: Option<&'a ExtensionDataInit>,
+    /// Effective request originator for the active thread, when resolution is thread-scoped.
+    originator: Option<&'a str>,
     /// Environment IDs whose selected roots may contribute to this exact step.
     available_environment_ids: Option<&'a [String]>,
 }
@@ -34,6 +36,7 @@ impl<'a, C> McpServerContributionContext<'a, C> {
             config,
             thread_store: None,
             thread_init: None,
+            originator: None,
             available_environment_ids: None,
         }
     }
@@ -43,12 +46,14 @@ impl<'a, C> McpServerContributionContext<'a, C> {
         config: &'a C,
         thread_init: &'a ExtensionDataInit,
         thread_store: &'a ExtensionData,
+        originator: &'a str,
         available_environment_ids: &'a [String],
     ) -> Self {
         Self {
             config,
             thread_store: Some(thread_store),
             thread_init: Some(thread_init),
+            originator: Some(originator),
             available_environment_ids: Some(available_environment_ids),
         }
     }
@@ -68,6 +73,11 @@ impl<'a, C> McpServerContributionContext<'a, C> {
         self.thread_init
     }
 
+    /// Returns the effective request originator when resolving for a running thread.
+    pub fn originator(&self) -> Option<&'a str> {
+        self.originator
+    }
+
     /// Returns the exact environment availability projection for a model step.
     ///
     /// `Some` means contributors must omit selected roots whose environment ID is absent from the

codex-rs/ext/mcp/src/lib.rs

@@ -32,6 +32,7 @@ impl McpServerContributor<Config> for HostedPluginRuntimeExtension {
                 config: Box::new(hosted_plugin_runtime_mcp_server_config(
                     &config.chatgpt_base_url,
                     config.apps_mcp_product_sku.as_deref(),
+                    context.originator(),
                 )),
             }]
         })
@@ -51,3 +52,7 @@ pub fn install_executor_plugins(
         executor_plugin::SelectedExecutorPluginMcpContributor::new(environment_manager),
     ));
 }
+
+#[cfg(test)]
+#[path = "lib_tests.rs"]
+mod tests;

codex-rs/ext/mcp/src/lib_tests.rs

@@ -0,0 +1,48 @@
+use super::*;
+use codex_config::McpServerTransportConfig;
+use codex_core::config::ConfigBuilder;
+use codex_extension_api::ExtensionData;
+use codex_extension_api::ExtensionDataInit;
+use pretty_assertions::assert_eq;
+
+#[tokio::test]
+async fn hosted_plugin_runtime_forwards_thread_originator() -> Result<(), Box<dyn std::error::Error>>
+{
+    let codex_home = tempfile::tempdir()?;
+    let config = ConfigBuilder::default()
+        .codex_home(codex_home.path().to_path_buf())
+        .fallback_cwd(Some(codex_home.path().to_path_buf()))
+        .cli_overrides(vec![
+            ("features.apps".to_string(), true.into()),
+            ("chatgpt_base_url".to_string(), "https://chatgpt.com".into()),
+        ])
+        .build()
+        .await?;
+    let thread_init = ExtensionDataInit::new();
+    let thread_store = ExtensionData::new("thread");
+
+    let contributions = HostedPluginRuntimeExtension
+        .contribute(McpServerContributionContext::for_step(
+            &config,
+            &thread_init,
+            &thread_store,
+            "codex_work_desktop",
+            /*available_environment_ids*/ &[],
+        ))
+        .await;
+    let [McpServerContribution::Set { config: server, .. }] = contributions.as_slice() else {
+        panic!("hosted plugin runtime should contribute one server");
+    };
+    let McpServerTransportConfig::StreamableHttp { http_headers, .. } = &server.transport else {
+        panic!("hosted plugin runtime should use streamable HTTP");
+    };
+
+    assert_eq!(
+        http_headers
+            .as_ref()
+            .and_then(|headers| headers.get("originator")),
+        Some(&"codex_work_desktop".to_string())
+    );
+
+    Ok(())
+}

codex-rs/ext/mcp/tests/executor_plugin_mcp.rs

@@ -202,6 +202,7 @@ async fn raw_selected_plugin_contributions(
             config,
             &thread_init,
             &thread_store,
+            "test_originator",
             &available_environment_ids,
         ))
         .await)