core: remove cross-crate re-exports from lib.rs (#16512)

## Why

`codex-core` was re-exporting APIs owned by sibling `codex-*` crates,
which made downstream crates depend on `codex-core` as a proxy module
instead of the actual owner crate.

Removing those forwards makes crate boundaries explicit and lets leaf
crates drop unnecessary `codex-core` dependencies. In this PR, this
reduces the dependency on `codex-core` to `codex-login` in the following
files:

```
codex-rs/backend-client/Cargo.toml
codex-rs/mcp-server/tests/common/Cargo.toml
```

## What

- Remove `codex-rs/core/src/lib.rs` re-exports for symbols owned by
`codex-login`, `codex-mcp`, `codex-rollout`, `codex-analytics`,
`codex-protocol`, `codex-shell-command`, `codex-sandboxing`,
`codex-tools`, and `codex-utils-path`.
- Delete the `default_client` forwarding shim in `codex-rs/core`.
- Update in-crate and downstream callsites to import directly from the
owning `codex-*` crate.
- Add direct Cargo dependencies where callsites now target the owner
crate, and remove `codex-core` from `codex-rs/backend-client`.

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

@@ -4,14 +4,14 @@ use base64::Engine;
 use chrono::Duration;
 use chrono::Utc;
 use codex_app_server_protocol::AuthMode;
-use codex_core::AuthManager;
-use codex_core::auth::AuthCredentialsStoreMode;
-use codex_core::auth::AuthDotJson;
-use codex_core::auth::REFRESH_TOKEN_URL_OVERRIDE_ENV_VAR;
-use codex_core::auth::RefreshTokenError;
-use codex_core::auth::load_auth_dot_json;
-use codex_core::auth::save_auth;
 use codex_core::error::RefreshTokenFailedReason;
+use codex_login::AuthCredentialsStoreMode;
+use codex_login::AuthDotJson;
+use codex_login::AuthManager;
+use codex_login::REFRESH_TOKEN_URL_OVERRIDE_ENV_VAR;
+use codex_login::RefreshTokenError;
+use codex_login::load_auth_dot_json;
+use codex_login::save_auth;
 use codex_login::token_data::IdTokenInfo;
 use codex_login::token_data::TokenData;
 use core_test_support::skip_if_no_network;

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

@@ -1,6 +1,6 @@
 use assert_cmd::Command as AssertCommand;
-use codex_core::auth::CODEX_API_KEY_ENV_VAR;
 use codex_git_utils::collect_git_info;
+use codex_login::CODEX_API_KEY_ENV_VAR;
 use codex_protocol::protocol::GitInfo;
 use codex_utils_cargo_bin::find_resource;
 use core_test_support::fs_wait;

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

@@ -1,24 +1,24 @@
-use codex_core::AuthManager;
-use codex_core::CodexAuth;
 use codex_core::ModelClient;
-use codex_core::ModelProviderAuthInfo;
 use codex_core::ModelProviderInfo;
 use codex_core::NewThread;
 use codex_core::Prompt;
 use codex_core::ResponseEvent;
 use codex_core::ThreadManager;
 use codex_core::WireApi;
-use codex_core::auth::AuthCredentialsStoreMode;
 use codex_core::built_in_model_providers;
-use codex_core::default_client::originator;
 use codex_core::error::CodexErr;
 use codex_core::models_manager::collaboration_mode_presets::CollaborationModesConfig;
 use codex_features::Feature;
+use codex_login::AuthCredentialsStoreMode;
+use codex_login::AuthManager;
+use codex_login::CodexAuth;
+use codex_login::default_client::originator;
 use codex_otel::SessionTelemetry;
 use codex_otel::TelemetryAuthMode;
 use codex_protocol::ThreadId;
 use codex_protocol::config_types::CollaborationMode;
 use codex_protocol::config_types::ModeKind;
+use codex_protocol::config_types::ModelProviderAuthInfo;
 use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::config_types::Settings;
 use codex_protocol::config_types::Verbosity;

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

@@ -1,7 +1,6 @@
 #![allow(clippy::expect_used, clippy::unwrap_used)]
 use codex_api::WS_REQUEST_HEADER_TRACEPARENT_CLIENT_METADATA_KEY;
 use codex_api::WS_REQUEST_HEADER_TRACESTATE_CLIENT_METADATA_KEY;
-use codex_core::CodexAuth;
 use codex_core::ModelClient;
 use codex_core::ModelClientSession;
 use codex_core::ModelProviderInfo;
@@ -10,6 +9,7 @@ use codex_core::ResponseEvent;
 use codex_core::WireApi;
 use codex_core::X_RESPONSESAPI_INCLUDE_TIMING_METRICS_HEADER;
 use codex_features::Feature;
+use codex_login::CodexAuth;
 use codex_otel::SessionTelemetry;
 use codex_otel::TelemetryAuthMode;
 use codex_otel::current_span_w3c_trace_context;

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

@@ -1,11 +1,11 @@
 #![allow(clippy::expect_used)]
-use codex_core::CodexAuth;
 use codex_core::ModelProviderInfo;
 use codex_core::built_in_model_providers;
 use codex_core::compact::SUMMARIZATION_PROMPT;
 use codex_core::compact::SUMMARY_PREFIX;
 use codex_core::config::Config;
 use codex_features::Feature;
+use codex_login::CodexAuth;
 use codex_protocol::items::TurnItem;
 use codex_protocol::openai_models::ModelInfo;
 use codex_protocol::openai_models::ModelsResponse;

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

@@ -4,8 +4,8 @@ use std::fs;
 use std::path::PathBuf;
 
 use anyhow::Result;
-use codex_core::CodexAuth;
 use codex_core::compact::SUMMARY_PREFIX;
+use codex_login::CodexAuth;
 use codex_protocol::items::TurnItem;
 use codex_protocol::models::ContentItem;
 use codex_protocol::models::ResponseItem;

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

@@ -843,7 +843,7 @@ async fn resume_conversation(
     path: std::path::PathBuf,
 ) -> Arc<CodexThread> {
     let auth_manager = codex_core::test_support::auth_manager_from_auth(
-        codex_core::CodexAuth::from_api_key("dummy"),
+        codex_login::CodexAuth::from_api_key("dummy"),
     );
     Box::pin(manager.resume_thread_from_rollout(
         config.clone(),

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

@@ -1,6 +1,6 @@
-use codex_core::CodexAuth;
 use codex_core::models_manager::collaboration_mode_presets::CollaborationModesConfig;
 use codex_core::models_manager::manager::ModelsManager;
+use codex_login::CodexAuth;
 use codex_protocol::openai_models::TruncationPolicyConfig;
 use core_test_support::load_default_config_for_test;
 use pretty_assertions::assert_eq;

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

@@ -1,8 +1,8 @@
 use anyhow::Result;
-use codex_core::CodexAuth;
 use codex_core::config::types::Personality;
 use codex_core::models_manager::manager::RefreshStrategy;
 use codex_features::Feature;
+use codex_login::CodexAuth;
 use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::config_types::ServiceTier;
 use codex_protocol::openai_models::ConfigShellToolType;

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

@@ -5,8 +5,8 @@ use anyhow::Result;
 use chrono::DateTime;
 use chrono::TimeZone;
 use chrono::Utc;
-use codex_core::CodexAuth;
 use codex_core::models_manager::manager::RefreshStrategy;
+use codex_login::CodexAuth;
 use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::openai_models::ConfigShellToolType;
 use codex_protocol::openai_models::ModelInfo;

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

@@ -3,7 +3,7 @@
 use std::sync::Arc;
 
 use anyhow::Result;
-use codex_core::CodexAuth;
+use codex_login::CodexAuth;
 use codex_protocol::openai_models::ModelsResponse;
 use codex_protocol::protocol::AskForApproval;
 use codex_protocol::protocol::EventMsg;

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

@@ -684,7 +684,7 @@ async fn remote_model_friendly_personality_instructions_with_feature() -> anyhow
     let resp_mock = mount_sse_once(&server, sse_completed("resp-1")).await;
 
     let mut builder = test_codex()
-        .with_auth(codex_core::CodexAuth::create_dummy_chatgpt_auth_for_testing())
+        .with_auth(codex_login::CodexAuth::create_dummy_chatgpt_auth_for_testing())
         .with_config(|config| {
             config
                 .features
@@ -804,7 +804,7 @@ async fn user_turn_personality_remote_model_template_includes_update_message() -
     .await;
 
     let mut builder = test_codex()
-        .with_auth(codex_core::CodexAuth::create_dummy_chatgpt_auth_for_testing())
+        .with_auth(codex_login::CodexAuth::create_dummy_chatgpt_auth_for_testing())
         .with_config(|config| {
             config
                 .features

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

@@ -6,8 +6,8 @@ use std::time::Duration;
 use std::time::Instant;
 
 use anyhow::Result;
-use codex_core::CodexAuth;
 use codex_features::Feature;
+use codex_login::CodexAuth;
 use codex_protocol::protocol::EventMsg;
 use codex_protocol::protocol::Op;
 use core_test_support::apps_test_server::AppsTestServer;
@@ -400,7 +400,7 @@ async fn explicit_plugin_mentions_track_plugin_used_analytics() -> Result<()> {
     );
     assert_eq!(
         event["event_params"]["product_client_id"],
-        serde_json::json!(codex_core::default_client::originator().value)
+        serde_json::json!(codex_login::default_client::originator().value)
     );
     assert_eq!(event["event_params"]["model_slug"], "gpt-5");
     assert!(event["event_params"]["thread_id"].as_str().is_some());

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

@@ -1,8 +1,8 @@
 use anyhow::Context;
 use anyhow::Result;
 use chrono::Utc;
-use codex_core::CodexAuth;
-use codex_core::auth::OPENAI_API_KEY_ENV_VAR;
+use codex_login::CodexAuth;
+use codex_login::OPENAI_API_KEY_ENV_VAR;
 use codex_protocol::ThreadId;
 use codex_protocol::protocol::CodexErrorInfo;
 use codex_protocol::protocol::ConversationAudioParams;

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

@@ -4,11 +4,11 @@
 use std::sync::Arc;
 
 use anyhow::Result;
-use codex_core::CodexAuth;
 use codex_core::ModelProviderInfo;
 use codex_core::built_in_model_providers;
 use codex_core::models_manager::manager::ModelsManager;
 use codex_core::models_manager::manager::RefreshStrategy;
+use codex_login::CodexAuth;
 use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::openai_models::ConfigShellToolType;
 use codex_protocol::openai_models::ModelInfo;

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

@@ -1,7 +1,7 @@
 #![cfg(not(target_os = "windows"))]
 
-use codex_core::CodexAuth;
 use codex_features::Feature;
+use codex_login::CodexAuth;
 use codex_protocol::protocol::EventMsg;
 use codex_protocol::protocol::Op;
 use codex_protocol::user_input::UserInput;

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

@@ -1,7 +1,7 @@
 #![allow(clippy::unwrap_used, clippy::expect_used)]
 
-use codex_core::CodexAuth;
 use codex_core::NewThread;
+use codex_login::CodexAuth;
 use codex_protocol::ThreadId;
 use codex_protocol::config_types::ModeKind;
 use codex_protocol::config_types::ReasoningSummary;

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

@@ -9,10 +9,10 @@ use std::time::Duration;
 use std::time::SystemTime;
 use std::time::UNIX_EPOCH;
 
-use codex_core::CodexAuth;
 use codex_core::config::types::McpServerConfig;
 use codex_core::config::types::McpServerTransportConfig;
 use codex_core::models_manager::manager::RefreshStrategy;
+use codex_login::CodexAuth;
 
 use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::openai_models::ConfigShellToolType;

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

@@ -2,9 +2,9 @@
 #![allow(clippy::unwrap_used, clippy::expect_used)]
 
 use anyhow::Result;
-use codex_core::CodexAuth;
 use codex_core::config::Config;
 use codex_features::Feature;
+use codex_login::CodexAuth;
 use codex_protocol::openai_models::ModelsResponse;
 use codex_protocol::protocol::AskForApproval;
 use codex_protocol::protocol::EventMsg;

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

@@ -2,10 +2,10 @@
 #![allow(clippy::unwrap_used, clippy::expect_used)]
 
 use anyhow::Result;
-use codex_core::CodexAuth;
 use codex_core::models_manager::manager::ModelsManager;
 use codex_core::models_manager::manager::RefreshStrategy;
 use codex_features::Feature;
+use codex_login::CodexAuth;
 use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::openai_models::ConfigShellToolType;
 use codex_protocol::openai_models::ModelInfo;

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

@@ -2,11 +2,11 @@
 #![allow(clippy::unwrap_used, clippy::expect_used)]
 
 use anyhow::Result;
-use codex_core::CodexAuth;
 use codex_core::config::Config;
 use codex_core::config::types::ToolSuggestDiscoverable;
 use codex_core::config::types::ToolSuggestDiscoverableType;
 use codex_features::Feature;
+use codex_login::CodexAuth;
 use codex_protocol::openai_models::ModelsResponse;
 use codex_protocol::protocol::AskForApproval;
 use codex_protocol::protocol::SandboxPolicy;

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

@@ -1,9 +1,9 @@
 #![allow(clippy::unwrap_used, clippy::expect_used)]
 
 use codex_config::CONFIG_TOML_FILE;
-use codex_core::CodexAuth;
 use codex_core::NewThread;
 use codex_features::Feature;
+use codex_login::CodexAuth;
 use codex_protocol::protocol::EventMsg;
 use codex_protocol::protocol::InitialHistory;
 use codex_protocol::protocol::WarningEvent;

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

@@ -2,9 +2,9 @@
 
 use base64::Engine;
 use base64::engine::general_purpose::STANDARD as BASE64_STANDARD;
-use codex_core::CodexAuth;
 use codex_exec_server::CreateDirectoryOptions;
 use codex_features::Feature;
+use codex_login::CodexAuth;
 use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::openai_models::ConfigShellToolType;
 use codex_protocol::openai_models::InputModality;