Move skill catalog rendering out of core (#36364)

## What changed

- Make the skills extension own the catalog prompt templates and rendering path.
- Remove the duplicate core fallback that injected available skills into initial context.
- Update core integration tests to install the skills extension explicitly when they expect model-visible skill context.

GitOrigin-RevId: bbe6b15c4e776a09c98b7f4166426fe4e58434ba

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

@@ -1,4 +1,3 @@
-use codex_config::ConfigLayerStack;
 use codex_config::types::AuthCredentialsStoreMode;
 use codex_core::ModelClient;
 use codex_core::NewThread;
@@ -54,7 +53,6 @@ use codex_protocol::protocol::SessionMeta;
 use codex_protocol::protocol::SessionMetaLine;
 use codex_protocol::protocol::SessionSource;
 use codex_protocol::user_input::UserInput;
-use core_test_support::PathBufExt;
 use core_test_support::TestCodexResponsesRequestKind;
 use core_test_support::apps_test_server::AppsTestServer;
 use core_test_support::load_default_config_for_test;
@@ -79,7 +77,6 @@ use core_test_support::test_codex::TestCodex;
 use core_test_support::test_codex::local_selections;
 use core_test_support::test_codex::test_codex;
 use core_test_support::wait_for_event;
-use dunce::canonicalize as normalize_path;
 use futures::StreamExt;
 use pretty_assertions::assert_eq;
 use serde_json::json;
@@ -87,7 +84,6 @@ use std::io::Write;
 use std::num::NonZeroU64;
 use std::sync::Arc;
 use tempfile::TempDir;
-use toml::toml;
 use uuid::Uuid;
 use wiremock::Mock;
 use wiremock::MockServer;
@@ -2204,172 +2200,6 @@ async fn omits_environment_context_when_configured_off() {
     );
 }
 
-#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
-async fn skills_append_to_developer_message() {
-    skip_if_no_network!();
-    let server = MockServer::start().await;
-
-    let resp_mock = mount_sse_once(
-        &server,
-        sse(vec![ev_response_created("resp1"), ev_completed("resp1")]),
-    )
-    .await;
-
-    let codex_home = Arc::new(TempDir::new().unwrap());
-    let skill_dir = codex_home.path().join("skills/demo");
-    std::fs::create_dir_all(&skill_dir).expect("create skill dir");
-    std::fs::write(
-        skill_dir.join("SKILL.md"),
-        "---\nname: demo\ndescription: build charts\n---\n\n# body\n",
-    )
-    .expect("write skill");
-
-    let codex_home_path = codex_home.path().to_path_buf();
-    let mut builder = test_codex()
-        .with_home(codex_home.clone())
-        .with_auth(CodexAuth::from_api_key("Test API Key"))
-        .with_config(move |config| {
-            config.cwd = codex_home_path.abs();
-        });
-    let codex = builder
-        .build(&server)
-        .await
-        .expect("create new conversation")
-        .codex;
-
-    codex
-        .submit(Op::UserInput {
-            items: vec![UserInput::Text {
-                text: "hello".into(),
-                text_elements: Vec::new(),
-            }],
-            final_output_json_schema: None,
-            responsesapi_client_metadata: None,
-            additional_context: Default::default(),
-            thread_settings: Default::default(),
-        })
-        .await
-        .unwrap();
-
-    wait_for_event(&codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
-
-    let request = resp_mock.single_request();
-    let developer_messages = request.message_input_texts("developer");
-    let developer_text = developer_messages.join("\n\n");
-    assert!(
-        developer_text.contains("## Skills"),
-        "expected skills section present: {developer_messages:?}"
-    );
-    assert!(
-        developer_text.contains("demo: build charts"),
-        "expected skill summary: {developer_messages:?}"
-    );
-    assert!(
-        developer_text.find("demo: build charts")
-            < developer_text.find("<permissions instructions>"),
-        "host skills should precede permissions: {developer_messages:?}"
-    );
-    let expected_path = normalize_path(skill_dir.join("SKILL.md")).unwrap();
-    let expected_path_str = expected_path.to_string_lossy().replace('\\', "/");
-    assert!(
-        developer_text.contains(&expected_path_str),
-        "expected path {expected_path_str} in developer message: {developer_messages:?}"
-    );
-    let _codex_home_guard = codex_home;
-}
-
-#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
-async fn skills_use_aliases_in_developer_message_under_budget_pressure() {
-    skip_if_no_network!();
-    let server = MockServer::start().await;
-
-    let resp_mock = mount_sse_once(
-        &server,
-        sse(vec![ev_response_created("resp1"), ev_completed("resp1")]),
-    )
-    .await;
-
-    let codex_home_parent = TempDir::new().unwrap();
-    let long_home_parent = codex_home_parent
-        .path()
-        .join("codex-home-with-long-shared-prefix-for-skill-alias-budget-test");
-    std::fs::create_dir_all(&long_home_parent).expect("create long home parent");
-    let codex_home = Arc::new(TempDir::new_in(long_home_parent).unwrap());
-    let skill_root = codex_home.path().join("skills");
-    for index in 0..12 {
-        let skill_dir = skill_root.join(format!("s{index:02}"));
-        std::fs::create_dir_all(&skill_dir).expect("create skill dir");
-        std::fs::write(
-            skill_dir.join("SKILL.md"),
-            format!("---\nname: s{index:02}\ndescription: d\n---\n\n# body\n"),
-        )
-        .expect("write skill");
-    }
-
-    let codex_home_path = codex_home.path().to_path_buf();
-    let mut builder = test_codex()
-        .with_home(codex_home.clone())
-        .with_auth(CodexAuth::from_api_key("Test API Key"))
-        .with_config(move |config| {
-            config.cwd = codex_home_path.abs();
-            let user_config_path = codex_home_path.join("config.toml").abs();
-            config.config_layer_stack = ConfigLayerStack::default()
-                .with_user_config(
-                    &user_config_path,
-                    toml! { skills = { bundled = { enabled = false } } }.into(),
-                )
-                .expect("skills user config should be valid");
-            config.model_context_window = Some(12_000);
-        });
-    let codex = builder
-        .build(&server)
-        .await
-        .expect("create new conversation")
-        .codex;
-
-    codex
-        .submit(Op::UserInput {
-            items: vec![UserInput::Text {
-                text: "hello".into(),
-                text_elements: Vec::new(),
-            }],
-            final_output_json_schema: None,
-            responsesapi_client_metadata: None,
-            additional_context: Default::default(),
-            thread_settings: Default::default(),
-        })
-        .await
-        .unwrap();
-
-    wait_for_event(&codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
-
-    let request = resp_mock.single_request();
-    let developer_messages = request.message_input_texts("developer");
-    let developer_text = developer_messages.join("\n\n");
-    let expected_root = normalize_path(skill_root).unwrap();
-    let expected_root_str = expected_root.to_string_lossy().replace('\\', "/");
-    assert!(
-        developer_text.contains("### Skill roots"),
-        "expected aliased skills root section: {developer_messages:?}"
-    );
-    assert!(
-        developer_text.contains(&format!("- `r0` = `{expected_root_str}`")),
-        "expected root alias for {expected_root_str}: {developer_messages:?}"
-    );
-    assert!(
-        developer_text.contains("- s00: d (file: r0/s00/SKILL.md)"),
-        "expected skill path to use root alias: {developer_messages:?}"
-    );
-    assert!(
-        developer_text.contains(
-            "expand the listed short `path` with the matching alias from `### Skill roots`"
-        ),
-        "expected alias-specific skill instructions: {developer_messages:?}"
-    );
-    let _codex_home_guard = codex_home;
-    let _codex_home_parent_guard = codex_home_parent;
-}
-
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn includes_configured_max_effort_in_request() -> anyhow::Result<()> {
     skip_if_no_network!(Ok(()));

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

@@ -4,7 +4,10 @@ use std::sync::Arc;
 
 use anyhow::Result;
 use codex_config::types::Personality;
+use codex_core::config::Config;
 use codex_exec_server::LOCAL_ENVIRONMENT_ID;
+use codex_extension_api::ExtensionRegistry;
+use codex_extension_api::ExtensionRegistryBuilder;
 use codex_features::Feature;
 use codex_protocol::models::PermissionProfile;
 use codex_protocol::protocol::AskForApproval;
@@ -13,6 +16,8 @@ use codex_protocol::protocol::Op;
 use codex_protocol::protocol::TurnEnvironmentSelection;
 use codex_protocol::protocol::TurnEnvironmentSelections;
 use codex_protocol::user_input::UserInput;
+use codex_skills_extension::SkillsExtensionConfig;
+use codex_skills_extension::install;
 use codex_utils_path_uri::PathUri;
 use core_test_support::PathBufExt;
 use core_test_support::context_snapshot;
@@ -34,6 +39,17 @@ use serde_json::json;
 
 const PRETURN_CONTEXT_DIFF_CWD: &str = "PRETURN_CONTEXT_DIFF_CWD";
 
+fn skills_extensions() -> Arc<ExtensionRegistry<Config>> {
+    let mut extensions = ExtensionRegistryBuilder::<Config>::new();
+    install(&mut extensions, |config: &Config| SkillsExtensionConfig {
+        include_instructions: config.include_skill_instructions,
+        bundled_skills_enabled: config.bundled_skills_enabled(),
+        orchestrator_skills_enabled: config.orchestrator_skills_enabled,
+        shadow_selection_enabled: config.features.enabled(Feature::SkillSearch),
+    });
+    Arc::new(extensions.build())
+}
+
 fn context_snapshot_options() -> ContextSnapshotOptions {
     ContextSnapshotOptions::default()
         .render_mode(ContextSnapshotRenderMode::KindWithTextPrefix { max_chars: 96 })
@@ -162,13 +178,16 @@ async fn snapshot_model_visible_layout_turn_overrides() -> Result<()> {
     )
     .await;
 
-    let mut builder = test_codex().with_model("gpt-5.4").with_config(|config| {
-        config
-            .features
-            .enable(Feature::Personality)
-            .expect("test config should allow feature update");
-        config.personality = Some(Personality::Pragmatic);
-    });
+    let mut builder = test_codex()
+        .with_extensions(skills_extensions())
+        .with_model("gpt-5.4")
+        .with_config(|config| {
+            config
+                .features
+                .enable(Feature::Personality)
+                .expect("test config should allow feature update");
+            config.personality = Some(Personality::Pragmatic);
+        });
     let test = builder.build(&server).await?;
     let preturn_context_diff_cwd = test.cwd_path().join(PRETURN_CONTEXT_DIFF_CWD);
     fs::create_dir_all(&preturn_context_diff_cwd)?;
@@ -282,7 +301,9 @@ async fn snapshot_model_visible_layout_cwd_change_refreshes_agents() -> Result<(
     )
     .await;
 
-    let mut builder = test_codex().with_model("gpt-5.4");
+    let mut builder = test_codex()
+        .with_extensions(skills_extensions())
+        .with_model("gpt-5.4");
     let test = builder.build(&server).await?;
     let cwd_one = test.cwd_path().join("agents_one");
     let cwd_two = test.cwd_path().join("agents_two");
@@ -396,9 +417,11 @@ async fn snapshot_model_visible_layout_resume_with_personality_change() -> Resul
     skip_if_no_network!(Ok(()));
 
     let server = start_mock_server().await;
-    let mut initial_builder = test_codex().with_config(|config| {
-        config.model = Some("gpt-5.2".to_string());
-    });
+    let mut initial_builder = test_codex()
+        .with_extensions(skills_extensions())
+        .with_config(|config| {
+            config.model = Some("gpt-5.2".to_string());
+        });
     let initial = initial_builder.build(&server).await?;
     let codex = Arc::clone(&initial.codex);
     let home = initial.home.clone();
@@ -442,14 +465,16 @@ async fn snapshot_model_visible_layout_resume_with_personality_change() -> Resul
     )
     .await;
 
-    let mut resume_builder = test_codex().with_config(|config| {
-        config.model = Some("gpt-5.4".to_string());
-        config
-            .features
-            .enable(Feature::Personality)
-            .expect("test config should allow feature update");
-        config.personality = Some(Personality::Pragmatic);
-    });
+    let mut resume_builder = test_codex()
+        .with_extensions(skills_extensions())
+        .with_config(|config| {
+            config.model = Some("gpt-5.4".to_string());
+            config
+                .features
+                .enable(Feature::Personality)
+                .expect("test config should allow feature update");
+            config.personality = Some(Personality::Pragmatic);
+        });
     let resumed = resume_builder.resume(&server, home, rollout_path).await?;
     let resume_override_cwd = resumed.cwd_path().join(PRETURN_CONTEXT_DIFF_CWD);
     fs::create_dir_all(&resume_override_cwd)?;
@@ -511,9 +536,11 @@ async fn snapshot_model_visible_layout_resume_override_matches_rollout_model() -
     skip_if_no_network!(Ok(()));
 
     let server = start_mock_server().await;
-    let mut initial_builder = test_codex().with_config(|config| {
-        config.model = Some("gpt-5.2".to_string());
-    });
+    let mut initial_builder = test_codex()
+        .with_extensions(skills_extensions())
+        .with_config(|config| {
+            config.model = Some("gpt-5.2".to_string());
+        });
     let initial = initial_builder.build(&server).await?;
     let codex = Arc::clone(&initial.codex);
     let home = initial.home.clone();
@@ -557,9 +584,11 @@ async fn snapshot_model_visible_layout_resume_override_matches_rollout_model() -
     )
     .await;
 
-    let mut resume_builder = test_codex().with_config(|config| {
-        config.model = Some("gpt-5.4".to_string());
-    });
+    let mut resume_builder = test_codex()
+        .with_extensions(skills_extensions())
+        .with_config(|config| {
+            config.model = Some("gpt-5.4".to_string());
+        });
     let resumed = resume_builder.resume(&server, home, rollout_path).await?;
     let resume_override_cwd = resumed.cwd_path().join(PRETURN_CONTEXT_DIFF_CWD);
     fs::create_dir_all(&resume_override_cwd)?;

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

@@ -6,7 +6,10 @@ use std::time::Duration;
 use std::time::Instant;
 
 use anyhow::Result;
+use codex_core::config::Config;
 use codex_core_plugins::store::PluginStore;
+use codex_extension_api::ExtensionRegistry;
+use codex_extension_api::ExtensionRegistryBuilder;
 use codex_features::Feature;
 use codex_login::CodexAuth;
 use codex_mcp::CODEX_APPS_MCP_SERVER_NAME;
@@ -19,6 +22,8 @@ use codex_protocol::protocol::AskForApproval;
 use codex_protocol::protocol::EventMsg;
 use codex_protocol::protocol::Op;
 use codex_protocol::user_input::UserInput;
+use codex_skills_extension::SkillsExtensionConfig;
+use codex_skills_extension::install;
 use core_test_support::apps_test_server::AppsTestServer;
 use core_test_support::apps_test_server::SEARCH_CALENDAR_CREATE_TOOL;
 use core_test_support::responses::ResponseMock;
@@ -59,6 +64,17 @@ const PLUGIN_APP_SEARCH_CALL_ID: &str = "plugin-app-search";
 const PLUGIN_MCP_SEARCH_CALL_ID: &str = "plugin-mcp-search";
 const REMOTE_PLUGIN_CONFIG_NAME: &str = "sample@openai-curated-remote";
 
+fn skills_extensions() -> Arc<ExtensionRegistry<Config>> {
+    let mut extensions = ExtensionRegistryBuilder::<Config>::new();
+    install(&mut extensions, |config: &Config| SkillsExtensionConfig {
+        include_instructions: config.include_skill_instructions,
+        bundled_skills_enabled: config.bundled_skills_enabled(),
+        orchestrator_skills_enabled: config.orchestrator_skills_enabled,
+        shadow_selection_enabled: config.features.enabled(Feature::SkillSearch),
+    });
+    Arc::new(extensions.build())
+}
+
 fn sample_plugin_root(home: &TempDir) -> std::path::PathBuf {
     home.path().join("plugins/cache/test/sample/local")
 }
@@ -408,12 +424,18 @@ async fn capability_sections_render_in_developer_message_in_order() -> Result<()
     let codex_home = Arc::new(TempDir::new()?);
     write_plugin_skill_plugin(codex_home.as_ref());
     write_plugin_app_plugin(codex_home.as_ref());
-    let test_codex = build_apps_enabled_plugin_test_codex(
-        &server,
-        Arc::clone(&codex_home),
-        apps_server.chatgpt_base_url,
-    )
-    .await?;
+    let mut builder = test_codex()
+        .with_home(Arc::clone(&codex_home))
+        .with_extensions(skills_extensions())
+        .with_auth(CodexAuth::create_dummy_chatgpt_auth_for_testing())
+        .with_config(move |config| {
+            config
+                .features
+                .enable(Feature::Apps)
+                .expect("test config should allow feature update");
+            config.chatgpt_base_url = apps_server.chatgpt_base_url;
+        });
+    let test_codex = builder.build(&server).await?;
     let codex = Arc::clone(&test_codex.codex);
 
     codex
@@ -645,6 +667,7 @@ enabled = true
 
         let mut builder = test_codex()
             .with_home(Arc::clone(&codex_home))
+            .with_extensions(skills_extensions())
             .with_auth(CodexAuth::create_dummy_chatgpt_auth_for_testing());
         let test_codex = builder.build_with_auto_env(&server).await?;
         let plugins_manager = test_codex.thread_manager.plugins_manager();

codex-rs/core/tests/suite/snapshots/all__suite__token_budget__token_budget_new_context_window_tool_full_context.snap

@@ -6,8 +6,8 @@ Scenario: New context window tool installs fresh full context before the next fo
 
 ## Final Follow-Up Request
 00:message/developer[3]:
-    [01] <SKILLS_INSTRUCTIONS>
-    [02] <context_window>\nThread id: <THREAD_ID>\nFirst context window id: <FIRST_WINDOW_ID>\nCurrent context window id: <WINDOW_ID>\nPrevious context window id: <FIRST_WINDOW_ID>\n</context_window>
+    [01] <context_window>\nThread id: <THREAD_ID>\nFirst context window id: <FIRST_WINDOW_ID>\nCurrent context window id: <WINDOW_ID>\nPrevious context window id: <FIRST_WINDOW_ID>\n</context_window>
+    [02] <SKILLS_INSTRUCTIONS>
     [03] <PERMISSIONS_INSTRUCTIONS>
 01:message/user:<ENVIRONMENT_CONTEXT:cwd=<CWD>>
 02:function_call/update_plan

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

@@ -2,7 +2,9 @@ use anyhow::Result;
 use codex_config::config_toml::ConfigLockfileToml;
 use codex_config::types::McpServerConfig;
 use codex_config::types::McpServerTransportConfig;
+use codex_core::config::Config;
 use codex_core::config::TokenBudgetConfig;
+use codex_extension_api::ExtensionRegistryBuilder;
 use codex_features::Feature;
 use codex_features::FeatureToml;
 use codex_features::TokenBudgetConfigToml;
@@ -22,6 +24,8 @@ use codex_protocol::protocol::ItemStartedEvent;
 use codex_protocol::protocol::Op;
 use codex_protocol::protocol::ThreadSettingsOverrides;
 use codex_protocol::user_input::UserInput;
+use codex_skills_extension::SkillsExtensionConfig;
+use codex_skills_extension::install;
 use core_test_support::PathBufExt;
 use core_test_support::assert_regex_match;
 use core_test_support::context_snapshot;
@@ -1483,7 +1487,15 @@ async fn new_context_tool_skips_auto_compact_fallback() -> Result<()> {
         ],
     )
     .await;
+    let mut extensions = ExtensionRegistryBuilder::<Config>::new();
+    install(&mut extensions, |config: &Config| SkillsExtensionConfig {
+        include_instructions: config.include_skill_instructions,
+        bundled_skills_enabled: config.bundled_skills_enabled(),
+        orchestrator_skills_enabled: config.orchestrator_skills_enabled,
+        shadow_selection_enabled: config.features.enabled(Feature::SkillSearch),
+    });
     let test = test_codex()
+        .with_extensions(Arc::new(extensions.build()))
         .with_config(|config| {
             config.model_context_window = Some(10_000);
             config.token_budget = Some(TokenBudgetConfig {