Forward turn metadata in standalone web search (#32835)

## What changed

- Add optional serialized Codex turn metadata to extension tool calls.
- Populate it from the current turn context and send it as the
  `x-codex-turn-metadata` header on standalone web search requests.

## Testing

- Extend the app-server web search integration test to verify that client
  metadata, including the model ID, reaches the standalone search request.

GitOrigin-RevId: c0950108d89a1d317ac94ccd23efcee72fffc6f0

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

@@ -1,3 +1,4 @@
+use std::collections::HashMap;
 use std::path::Path;
 use std::time::Duration;
 
@@ -44,6 +45,18 @@ const DEFAULT_READ_TIMEOUT: Duration = Duration::from_secs(10);
 #[tokio::test]
 async fn standalone_web_search_round_trips_output() -> Result<()> {
     let call_id = "web-run-1";
+    let expected_model_id = "model-id-from-search-context";
+    let search_context = json!({
+        "telemetry_attributes": {
+            "model_id": expected_model_id,
+            "model_slug": "mock-model",
+        }
+    })
+    .to_string();
+    let client_metadata = HashMap::from([(
+        "mcp_request_meta".to_string(),
+        json!({ "openai/search_context": search_context }).to_string(),
+    )]);
     let server = responses::start_mock_server().await;
     mount_search_response(&server).await;
 
@@ -105,6 +118,7 @@ async fn standalone_web_search_round_trips_output() -> Result<()> {
                 text: "Search the web".to_string(),
                 text_elements: Vec::new(),
             }],
+            responsesapi_client_metadata: Some(client_metadata.clone()),
             ..Default::default()
         })
         .await?;
@@ -144,7 +158,10 @@ async fn standalone_web_search_round_trips_output() -> Result<()> {
         "standalone web search should replace hosted web search"
     );
 
-    let search_body = search_request_body(&server).await?;
+    let search_request = search_request(&server).await?;
+    let search_body = search_request
+        .body_json::<Value>()
+        .context("search request body should be JSON")?;
     assert_eq!(search_body["model"], json!("mock-model"));
     assert_eq!(
         search_body["commands"],
@@ -169,6 +186,30 @@ async fn standalone_web_search_round_trips_output() -> Result<()> {
             "content": [{"type": "input_text", "text": "Search the web"}],
         }))
     );
+    let turn_metadata_header = search_request
+        .headers
+        .get("x-codex-turn-metadata")
+        .context("standalone search should include x-codex-turn-metadata")?
+        .to_str()
+        .context("x-codex-turn-metadata should be valid ASCII")?;
+    let turn_metadata: Value = serde_json::from_str(turn_metadata_header)
+        .context("x-codex-turn-metadata should be valid JSON")?;
+    let mcp_request_meta = turn_metadata["mcp_request_meta"]
+        .as_str()
+        .context("mcp_request_meta should be a JSON string")?;
+    let mcp_request_meta: Value = serde_json::from_str(mcp_request_meta)
+        .context("mcp_request_meta should contain valid JSON")?;
+    let search_context = mcp_request_meta["openai/search_context"]
+        .as_str()
+        .context("openai/search_context should be a JSON string")?;
+    let search_context: Value = serde_json::from_str(search_context)
+        .context("openai/search_context should contain valid JSON")?;
+    assert_eq!(
+        search_context
+            .pointer("/telemetry_attributes/model_id")
+            .and_then(Value::as_str),
+        Some(expected_model_id)
+    );
 
     assert_eq!(
         responses::strip_metadata_from_json(requests[1].function_call_output(call_id)),
@@ -285,16 +326,15 @@ fn has_hosted_web_search(body: &Value) -> bool {
         })
 }
 
-async fn search_request_body(server: &MockServer) -> Result<Value> {
+async fn search_request(server: &MockServer) -> Result<wiremock::Request> {
-    server
+    let requests = server
         .received_requests()
         .await
-        .context("failed to fetch received requests")?
+        .context("failed to fetch received requests")?;
+    requests
         .into_iter()
         .find(|request| request.url.path() == "/api/codex/alpha/search")
-        .context("expected standalone search request")?
+        .context("expected standalone search request")
-        .body_json()
-        .context("search request body should be JSON")
 }
 
 fn create_config_toml(codex_home: &Path, server_uri: &str) -> std::io::Result<()> {

codex-rs/core/src/tools/handlers/extension_tools.rs

@@ -13,6 +13,7 @@ use codex_tools::ToolSearchInfo;
 use codex_tools::ToolSpec;
 use codex_tools::TurnItemEmissionFuture;
 use codex_tools::TurnItemEmitter;
+use codex_utils_string::to_ascii_json_string;
 
 use crate::sandboxing::SandboxPermissions;
 use crate::session::session::Session;
@@ -22,6 +23,7 @@ use crate::tools::context::ToolPayload;
 use crate::tools::handlers::apply_granted_turn_permissions;
 use crate::tools::registry::CoreToolRuntime;
 use crate::tools::registry::ToolExecutor;
+use crate::turn_metadata::McpTurnMetadataContext;
 
 pub(crate) struct ExtensionToolAdapter(Arc<dyn codex_tools::ToolExecutor<ExtensionToolCall>>);
 
@@ -114,6 +116,14 @@ impl TurnItemEmitter for CoreTurnItemEmitter {
 async fn to_extension_call(invocation: &ToolInvocation) -> ExtensionToolCall {
     let conversation_history =
         ConversationHistory::new(invocation.session.clone_history().await.into_raw_items());
+    let codex_turn_metadata = invocation
+        .turn
+        .turn_metadata_state
+        .current_meta_value_for_mcp_request(McpTurnMetadataContext {
+            model: invocation.turn.model_info.slug.as_str(),
+            reasoning_effort: invocation.turn.effective_reasoning_effort(),
+        })
+        .and_then(|metadata| to_ascii_json_string(&metadata).ok());
     let mut environments =
         Vec::with_capacity(invocation.step_context.environments.turn_environments.len());
     for environment in &invocation.step_context.environments.turn_environments {
@@ -146,6 +156,7 @@ async fn to_extension_call(invocation: &ToolInvocation) -> ExtensionToolCall {
         call_id: invocation.call_id.clone(),
         tool_name: invocation.tool_name.clone(),
         model: invocation.turn.model_info.slug.clone(),
+        codex_turn_metadata,
         truncation_policy: invocation.turn.model_info.truncation_policy.into(),
         conversation_history,
         turn_item_emitter: Arc::new(CoreTurnItemEmitter {

codex-rs/ext/goal/tests/goal_extension_backend.rs

@@ -1343,6 +1343,7 @@ fn tool_call(tool_name: &str, call_id: &str, arguments: serde_json::Value) -> To
         call_id: call_id.to_string(),
         tool_name: codex_extension_api::ToolName::plain(tool_name),
         model: "gpt-test".to_string(),
+        codex_turn_metadata: None,
         truncation_policy: TruncationPolicy::Bytes(1024),
         conversation_history: codex_extension_api::ConversationHistory::default(),
         turn_item_emitter: Arc::new(NoopTurnItemEmitter),

codex-rs/ext/memories/src/tests.rs

@@ -212,6 +212,7 @@ async fn add_ad_hoc_note_tool_creates_note_file() {
             call_id: "call-1".to_string(),
             tool_name: memory_tool_name(crate::ADD_AD_HOC_NOTE_TOOL_NAME),
             model: "gpt-test".to_string(),
+            codex_turn_metadata: None,
             truncation_policy: TruncationPolicy::Bytes(1024),
             conversation_history: codex_extension_api::ConversationHistory::default(),
             turn_item_emitter: Arc::new(NoopTurnItemEmitter),
@@ -256,6 +257,7 @@ async fn add_ad_hoc_note_tool_rejects_paths_as_filenames() {
             call_id: "call-1".to_string(),
             tool_name: memory_tool_name(crate::ADD_AD_HOC_NOTE_TOOL_NAME),
             model: "gpt-test".to_string(),
+            codex_turn_metadata: None,
             truncation_policy: TruncationPolicy::Bytes(1024),
             conversation_history: codex_extension_api::ConversationHistory::default(),
             turn_item_emitter: Arc::new(NoopTurnItemEmitter),
@@ -301,6 +303,7 @@ async fn read_tool_reads_memory_file() {
             call_id: "call-1".to_string(),
             tool_name: memory_tool_name(crate::READ_TOOL_NAME),
             model: "gpt-test".to_string(),
+            codex_turn_metadata: None,
             truncation_policy: TruncationPolicy::Bytes(1024),
             conversation_history: codex_extension_api::ConversationHistory::default(),
             turn_item_emitter: Arc::new(NoopTurnItemEmitter),
@@ -349,6 +352,7 @@ async fn search_tool_accepts_multiple_queries() {
             call_id: "call-1".to_string(),
             tool_name: memory_tool_name(crate::SEARCH_TOOL_NAME),
             model: "gpt-test".to_string(),
+            codex_turn_metadata: None,
             truncation_policy: TruncationPolicy::Bytes(1024),
             conversation_history: codex_extension_api::ConversationHistory::default(),
             turn_item_emitter: Arc::new(NoopTurnItemEmitter),
@@ -423,6 +427,7 @@ async fn search_tool_accepts_windowed_all_match_mode() {
             call_id: "call-1".to_string(),
             tool_name: memory_tool_name(crate::SEARCH_TOOL_NAME),
             model: "gpt-test".to_string(),
+            codex_turn_metadata: None,
             truncation_policy: TruncationPolicy::Bytes(1024),
             conversation_history: codex_extension_api::ConversationHistory::default(),
             turn_item_emitter: Arc::new(NoopTurnItemEmitter),
@@ -477,6 +482,7 @@ async fn search_tool_rejects_legacy_single_query() {
             call_id: "call-1".to_string(),
             tool_name: memory_tool_name(crate::SEARCH_TOOL_NAME),
             model: "gpt-test".to_string(),
+            codex_turn_metadata: None,
             truncation_policy: TruncationPolicy::Bytes(1024),
             conversation_history: codex_extension_api::ConversationHistory::default(),
             turn_item_emitter: Arc::new(NoopTurnItemEmitter),

codex-rs/ext/skills/tests/skills_extension.rs

@@ -438,6 +438,7 @@ async fn skills_list_truncates_catalog_descriptions_in_tool_output() -> TestResu
             call_id: "call-1".to_string(),
             tool_name: list_tool.tool_name(),
             model: "gpt-test".to_string(),
+            codex_turn_metadata: None,
             truncation_policy: TruncationPolicy::Bytes(1_024),
             conversation_history: ConversationHistory::default(),
             turn_item_emitter: Arc::new(NoopTurnItemEmitter),

codex-rs/ext/web-search/src/tool.rs

@@ -4,6 +4,7 @@ use codex_api::SearchCommands;
 use codex_api::SearchQuery;
 use codex_api::SearchRequest;
 use codex_api::SearchSettings;
+use codex_core::X_CODEX_TURN_METADATA_HEADER;
 use codex_core::web_search_action_detail;
 use codex_extension_api::ExtensionTurnItem;
 use codex_extension_api::FunctionCallError;
@@ -28,6 +29,7 @@ use codex_tools::ResponsesApiNamespaceTool;
 use codex_tools::ToolExposure;
 use codex_tools::default_namespace_description;
 use http::HeaderMap;
+use http::HeaderValue;
 use url::Url;
 
 use crate::history::recent_input;
@@ -113,6 +115,12 @@ impl WebSearchTool {
                 u64::try_from(call.truncation_policy.token_budget()).unwrap_or(u64::MAX),
             ),
         };
+        let mut extra_headers = HeaderMap::new();
+        if let Some(turn_metadata) = call.codex_turn_metadata.as_deref()
+            && let Ok(header_value) = HeaderValue::from_str(turn_metadata)
+        {
+            extra_headers.insert(X_CODEX_TURN_METADATA_HEADER, header_value);
+        }
         call.turn_item_emitter
             .emit_started(extension_turn_item(
                 WebSearchItem {
@@ -126,7 +134,7 @@ impl WebSearchTool {
             ))
             .await;
         let response = client
-            .search(&request, HeaderMap::new())
+            .search(&request, extra_headers)
             .await
             .map_err(|err| FunctionCallError::Fatal(err.to_string()))?;
         let legacy_action = match &command_action {

codex-rs/tools/src/tool_call.rs

@@ -92,6 +92,7 @@ pub struct ToolCall {
     pub call_id: String,
     pub tool_name: ToolName,
     pub model: String,
+    pub codex_turn_metadata: Option<String>,
     pub truncation_policy: TruncationPolicy,
     pub conversation_history: ConversationHistory,
     pub turn_item_emitter: Arc<dyn TurnItemEmitter>,
@@ -106,6 +107,10 @@ impl std::fmt::Debug for ToolCall {
             .field("call_id", &self.call_id)
             .field("tool_name", &self.tool_name)
             .field("model", &self.model)
+            .field(
+                "has_codex_turn_metadata",
+                &self.codex_turn_metadata.is_some(),
+            )
             .field("truncation_policy", &self.truncation_policy)
             .field("conversation_history", &self.conversation_history)
             .field("turn_item_emitter", &"<host turn item emitter>")