core: route Responses API through system proxy

codex-rs/core/Cargo.toml

@@ -49,6 +49,7 @@ codex-shell-command = { workspace = true }
 codex-execpolicy = { workspace = true }
 codex-git-utils = { workspace = true }
 codex-hooks = { workspace = true }
+codex-http-client = { workspace = true }
 codex-install-context = { workspace = true }
 codex-network-proxy = { workspace = true }
 codex-otel = { workspace = true }

codex-rs/core/src/client.rs

@@ -62,10 +62,13 @@ use codex_api::auth_header_telemetry;
 use codex_api::build_session_headers;
 use codex_api::create_text_param_for_request;
 use codex_api::response_create_client_metadata;
+use codex_http_client::ClientRouteClass;
+use codex_http_client::HttpClientFactory;
 use codex_login::AuthManager;
 use codex_login::CodexAuth;
 use codex_login::RefreshTokenError;
 use codex_login::UnauthorizedRecovery;
+use codex_login::default_client::build_default_reqwest_client_for_route;
 use codex_login::default_client::build_reqwest_client;
 use codex_otel::SessionTelemetry;
 use codex_otel::current_span_w3c_trace_context;
@@ -248,6 +251,7 @@ pub struct ModelClient {
     state: Arc<ModelClientState>,
     agent_identity_policy: AgentIdentityAuthPolicy,
     prompt_cache_key_override: Option<String>,
+    http_client_factory: HttpClientFactory,
 }
 
 /// A turn-scoped streaming session created from a [`ModelClient`].
@@ -396,7 +400,9 @@ impl ModelClient {
     /// Creates a new session-scoped `ModelClient`.
     ///
     /// All arguments are expected to be stable for the lifetime of a Codex session. Per-turn values
-    /// are passed to [`ModelClientSession::stream`] (and other turn-scoped methods) explicitly.
+    /// are passed to [`ModelClientSession::stream`] (and other turn-scoped methods) explicitly. The
+    /// HTTP client factory must come from the effective session configuration so every transport
+    /// observes the resolved outbound proxy policy.
     pub fn new(
         auth_manager: Option<Arc<AuthManager>>,
         agent_identity_policy: AgentIdentityAuthPolicy,
@@ -410,6 +416,7 @@ impl ModelClient {
         beta_features_header: Option<String>,
         item_ids_enabled: bool,
         attestation_provider: Option<Arc<dyn AttestationProvider>>,
+        http_client_factory: HttpClientFactory,
     ) -> Self {
         let model_provider = create_model_provider(provider_info, auth_manager);
         let codex_api_key_env_enabled = model_provider
@@ -439,6 +446,7 @@ impl ModelClient {
             }),
             agent_identity_policy,
             prompt_cache_key_override: None,
+            http_client_factory,
         }
     }
 
@@ -532,7 +540,8 @@ impl ModelClient {
             return Ok(Vec::new());
         }
         let client_setup = self.current_client_setup().await?;
-        let transport = ReqwestTransport::new(build_reqwest_client());
+        let transport =
+            self.build_responses_transport(&client_setup.api_provider, RESPONSES_COMPACT_ENDPOINT)?;
         let request_telemetry = Self::build_request_telemetry(
             session_telemetry,
             AuthRequestTelemetryContext::new(
@@ -938,6 +947,21 @@ impl ModelClient {
         })
     }
 
+    fn build_responses_transport(
+        &self,
+        api_provider: &ApiProvider,
+        endpoint: &str,
+    ) -> Result<ReqwestTransport> {
+        let request_url = api_provider.url_for_path(endpoint);
+        let client = build_default_reqwest_client_for_route(
+            &self.http_client_factory,
+            &request_url,
+            ClientRouteClass::Api,
+        )
+        .map_err(std::io::Error::from)?;
+        Ok(ReqwestTransport::new(client))
+    }
+
     pub(crate) async fn prewarm_auth(&self) -> Result<()> {
         self.current_client_setup().await.map(|_| ())
     }
@@ -1372,7 +1396,9 @@ impl ModelClientSession {
         let mut pending_retry = PendingUnauthorizedRetry::default();
         loop {
             let client_setup = self.client.current_client_setup().await?;
-            let transport = ReqwestTransport::new(build_reqwest_client());
+            let transport = self
+                .client
+                .build_responses_transport(&client_setup.api_provider, RESPONSES_ENDPOINT)?;
             let request_auth_context = AuthRequestTelemetryContext::new(
                 client_setup.auth.as_ref().map(CodexAuth::auth_mode),
                 client_setup.api_auth.as_ref(),

codex-rs/core/src/client_tests.rs

@@ -19,6 +19,8 @@ use codex_api::AgentIdentityTelemetry;
 use codex_api::ApiError;
 use codex_api::ResponseEvent;
 use codex_api::TransportError;
+use codex_http_client::HttpClientFactory;
+use codex_http_client::OutboundProxyPolicy;
 use codex_login::AuthCredentialsStoreMode;
 use codex_login::AuthKeyringBackendKind;
 use codex_login::AuthManager;
@@ -104,6 +106,7 @@ fn test_model_client_with_thread_id(
         /*beta_features_header*/ None,
         /*item_ids_enabled*/ false,
         /*attestation_provider*/ None,
+        HttpClientFactory::new(OutboundProxyPolicy::ReqwestDefault),
     )
 }
 
@@ -148,6 +151,7 @@ async fn compact_uses_bearer_after_agent_identity_session_fallback() -> anyhow::
         /*beta_features_header*/ None,
         /*item_ids_enabled*/ false,
         /*attestation_provider*/ None,
+        HttpClientFactory::new(OutboundProxyPolicy::ReqwestDefault),
     );
     let prompt = Prompt {
         input: vec![ResponseItem::Message {
@@ -824,6 +828,7 @@ fn model_client_with_counting_attestation(
         Some(Arc::new(CountingAttestationProvider {
             calls: attestation_calls.clone(),
         })),
+        HttpClientFactory::new(OutboundProxyPolicy::ReqwestDefault),
     );
     (model_client, attestation_calls)
 }

codex-rs/core/src/config/config_tests.rs

@@ -1590,6 +1590,10 @@ respect_system_proxy = true
     .await?;
 
     assert!(config.respect_system_proxy);
+    assert_eq!(
+        config.http_client_factory().outbound_proxy_policy(),
+        codex_http_client::OutboundProxyPolicy::RespectSystemProxy
+    );
     Ok(())
 }
 

codex-rs/core/src/config/mod.rs

@@ -70,6 +70,8 @@ use codex_features::MultiAgentV2ConfigToml;
 use codex_features::NetworkProxyConfigToml;
 use codex_features::TokenBudgetConfigToml;
 use codex_git_utils::resolve_root_git_project_for_trust;
+use codex_http_client::HttpClientFactory;
+use codex_http_client::OutboundProxyPolicy;
 use codex_install_context::InstallContext;
 use codex_login::AuthManagerConfig;
 use codex_login::AuthRouteConfig;
@@ -1481,6 +1483,16 @@ impl Config {
             .then(AuthRouteConfig::respect_system_proxy)
     }
 
+    /// Creates the HTTP client factory resolved from the effective feature configuration.
+    pub fn http_client_factory(&self) -> HttpClientFactory {
+        let outbound_proxy_policy = if self.respect_system_proxy {
+            OutboundProxyPolicy::RespectSystemProxy
+        } else {
+            OutboundProxyPolicy::ReqwestDefault
+        };
+        HttpClientFactory::new(outbound_proxy_policy)
+    }
+
     /// Build the plugin-manager input from the effective config.
     pub fn plugins_config_input(&self) -> PluginsConfigInput {
         PluginsConfigInput::new(

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

@@ -1112,6 +1112,7 @@ impl Session {
                     Self::build_model_client_beta_features_header(config.as_ref()),
                     /*item_ids_enabled*/ config.features.enabled(Feature::ItemIds),
                     attestation_provider,
+                    config.http_client_factory(),
                 )
                 .with_prompt_cache_key_override(
                     crate::guardian::prompt_cache_key_override_for_review_session(

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

@@ -33,6 +33,8 @@ use codex_core_skills::HostSkillsSnapshot;
 use core_test_support::test_codex::local_selections;
 
 use codex_features::Feature;
+use codex_http_client::HttpClientFactory;
+use codex_http_client::OutboundProxyPolicy;
 use codex_login::CodexAuth;
 use codex_login::auth::AgentIdentityAuthPolicy;
 use codex_model_provider_info::ModelProviderInfo;
@@ -491,6 +493,7 @@ fn test_model_client_session() -> crate::client::ModelClientSession {
         /*beta_features_header*/ None,
         /*item_ids_enabled*/ false,
         /*attestation_provider*/ None,
+        HttpClientFactory::new(OutboundProxyPolicy::ReqwestDefault),
     )
     .new_session()
 }
@@ -5461,6 +5464,7 @@ pub(crate) async fn make_session_and_context() -> (Session, TurnContext) {
             Session::build_model_client_beta_features_header(config.as_ref()),
             /*item_ids_enabled*/ config.features.enabled(Feature::ItemIds),
             /*attestation_provider*/ None,
+            config.http_client_factory(),
         ),
         code_mode_service: crate::tools::code_mode::CodeModeService::new(Arc::new(
             codex_code_mode::InProcessCodeModeSessionProvider,
@@ -7587,6 +7591,7 @@ where
             Session::build_model_client_beta_features_header(config.as_ref()),
             /*item_ids_enabled*/ config.features.enabled(Feature::ItemIds),
             /*attestation_provider*/ None,
+            config.http_client_factory(),
         ),
         code_mode_service: crate::tools::code_mode::CodeModeService::new(Arc::new(
             codex_code_mode::InProcessCodeModeSessionProvider,

codex-rs/core/tests/responses_headers.rs

@@ -132,6 +132,7 @@ async fn responses_stream_includes_subagent_header_on_review() {
         /*beta_features_header*/ None,
         /*item_ids_enabled*/ false,
         /*attestation_provider*/ None,
+        config.http_client_factory(),
     );
     let responses_metadata = test_turn_responses_metadata(&client, thread_id, &session_source);
     let mut client_session = client.new_session();
@@ -266,6 +267,7 @@ async fn responses_stream_includes_subagent_header_on_other() {
         /*beta_features_header*/ None,
         /*item_ids_enabled*/ false,
         /*attestation_provider*/ None,
+        config.http_client_factory(),
     );
     let responses_metadata = test_turn_responses_metadata(&client, thread_id, &session_source);
     let mut client_session = client.new_session();
@@ -386,6 +388,7 @@ async fn responses_respects_model_info_overrides_from_config() {
         /*beta_features_header*/ None,
         /*item_ids_enabled*/ false,
         /*attestation_provider*/ None,
+        config.http_client_factory(),
     );
     let responses_metadata = test_turn_responses_metadata(&client, thread_id, &session_source);
     let mut client_session = client.new_session();

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

@@ -1335,6 +1335,7 @@ async fn send_provider_auth_request(server: &MockServer, auth: ModelProviderAuth
         /*beta_features_header*/ None,
         /*item_ids_enabled*/ config.features.enabled(Feature::ItemIds),
         /*attestation_provider*/ None,
+        config.http_client_factory(),
     );
     let responses_metadata = test_turn_responses_metadata(&client, thread_id);
     let mut client_session = client.new_session();
@@ -2949,6 +2950,7 @@ async fn azure_responses_request_includes_store_and_reasoning_ids() {
         /*beta_features_header*/ None,
         /*item_ids_enabled*/ false,
         /*attestation_provider*/ None,
+        config.http_client_factory(),
     );
     let responses_metadata = test_turn_responses_metadata(&client, thread_id);
     let mut client_session = client.new_session();

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

@@ -2252,6 +2252,7 @@ async fn websocket_harness_with_provider_options(
         /*beta_features_header*/ None,
         /*item_ids_enabled*/ config.features.enabled(Feature::ItemIds),
         /*attestation_provider*/ None,
+        config.http_client_factory(),
     );
 
     WebsocketTestHarness {

codex-rs/http-client/src/lib.rs

@@ -25,9 +25,9 @@ pub use crate::error::StreamError;
 pub use crate::error::TransportError;
 pub use crate::outbound_proxy::BuildRouteAwareHttpClientError;
 pub use crate::outbound_proxy::ClientRouteClass;
-pub use crate::outbound_proxy::OutboundProxyConfig;
+pub use crate::outbound_proxy::HttpClientFactory;
+pub use crate::outbound_proxy::OutboundProxyPolicy;
 pub use crate::outbound_proxy::RouteFailureClass;
-pub use crate::outbound_proxy::build_reqwest_client_for_route;
 pub use crate::request::EncodedJsonBody;
 pub use crate::request::PreparedRequestBody;
 pub use crate::request::Request;

codex-rs/http-client/src/outbound_proxy.rs

@@ -84,14 +84,54 @@ impl fmt::Display for RouteFailureClass {
     }
 }
 
-/// Marker enabling fixed system/PAC/WPAD, environment, then direct routing.
-/// Resolved endpoints and platform details remain internal to the client builder.
+/// Resolved outbound proxy behavior for HTTP clients.
+///
+/// Callers must choose a policy explicitly so omitting feature resolution cannot silently select
+/// legacy behavior.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub struct OutboundProxyConfig;
+pub enum OutboundProxyPolicy {
+    /// Preserve reqwest's built-in proxy behavior.
+    ReqwestDefault,
+    /// Resolve system/PAC/WPAD settings, then environment settings, then direct routing.
+    RespectSystemProxy,
+}
+
+/// Builds route-specific HTTP clients using one resolved outbound proxy policy.
+///
+/// Construct this once from the effective application configuration and carry it with the
+/// session or component that owns outbound requests. Individual request paths should supply only
+/// their destination and route class rather than resolving feature state themselves.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct HttpClientFactory {
+    outbound_proxy_policy: OutboundProxyPolicy,
+}
+
+impl HttpClientFactory {
+    /// Creates a factory from the outbound proxy policy resolved by the application.
+    pub const fn new(outbound_proxy_policy: OutboundProxyPolicy) -> Self {
+        Self {
+            outbound_proxy_policy,
+        }
+    }
+
+    /// Returns the outbound proxy policy used for clients built by this factory.
+    pub const fn outbound_proxy_policy(&self) -> OutboundProxyPolicy {
+        self.outbound_proxy_policy
+    }
 
-impl OutboundProxyConfig {
-    pub const fn respect_system_proxy() -> Self {
-        Self
+    /// Builds a reqwest client for a concrete outbound route.
+    pub fn build_reqwest_client(
+        &self,
+        builder: reqwest::ClientBuilder,
+        request_url: &str,
+        route_class: ClientRouteClass,
+    ) -> Result<reqwest::Client, BuildRouteAwareHttpClientError> {
+        build_reqwest_client_for_route(
+            builder,
+            request_url,
+            route_class,
+            self.outbound_proxy_policy,
+        )
     }
 }
 
@@ -120,18 +160,18 @@ impl From<BuildRouteAwareHttpClientError> for io::Error {
 /// a route is selected are returned without trying another route. Ordered PAC candidates are
 /// currently collapsed to one route on both Windows and macOS; later proxy or `DIRECT` candidates
 /// are not retried after a connection failure.
-pub fn build_reqwest_client_for_route(
+fn build_reqwest_client_for_route(
     builder: reqwest::ClientBuilder,
     request_url: &str,
     route_class: ClientRouteClass,
-    config: Option<&OutboundProxyConfig>,
+    outbound_proxy_policy: OutboundProxyPolicy,
 ) -> Result<reqwest::Client, BuildRouteAwareHttpClientError> {
     let builder = configure_proxy_for_route(
         &ProcessEnv,
         builder,
         request_url,
         route_class,
-        config,
+        outbound_proxy_policy,
         resolve_system_proxy,
     )?;
     build_reqwest_client_with_custom_ca(builder).map_err(Into::into)
@@ -142,10 +182,10 @@ fn configure_proxy_for_route(
     builder: reqwest::ClientBuilder,
     request_url: &str,
     route_class: ClientRouteClass,
-    config: Option<&OutboundProxyConfig>,
+    outbound_proxy_policy: OutboundProxyPolicy,
     resolve_system_proxy: impl FnOnce(&str, &RequestOrigin) -> SystemProxyDecision,
 ) -> Result<reqwest::ClientBuilder, BuildRouteAwareHttpClientError> {
-    if config.is_none() {
+    if matches!(outbound_proxy_policy, OutboundProxyPolicy::ReqwestDefault) {
         return Ok(builder);
     }
     let origin = RequestOrigin::parse(request_url);

codex-rs/http-client/src/outbound_proxy_tests.rs

@@ -79,13 +79,12 @@ async fn enabled_environment_proxy_routes_request_through_proxy() {
         values: HashMap::from([("HTTP_PROXY".to_string(), format!("http://{proxy_addr}"))]),
     };
     let request_url = "http://enabled-proxy.test/proxy-check";
-    let config = OutboundProxyConfig::respect_system_proxy();
     let builder = configure_proxy_for_route(
         &env,
         reqwest::Client::builder().timeout(Duration::from_secs(2)),
         request_url,
         ClientRouteClass::Auth,
-        Some(&config),
+        OutboundProxyPolicy::RespectSystemProxy,
         |_, _| SystemProxyDecision::Unavailable {
             failure: RouteFailureClass::ProxyResolutionUnavailable,
         },