[codex] [3/4] Activate endpoint plugin recommendations (#27704)

Summary\n- Await endpoint recommendation selection while constructing
each authenticated turn, removing the first-turn cache race.\n- Snapshot
and filter endpoint candidates once per turn, then use that same set for
the bounded contextual user fragment, tool exposure, and exact install
validation.\n- Keep recommendation selection ephemeral: do not persist
recommendation state in or gate resumed threads on prior context.\n-
Hide the legacy list tool in endpoint mode and preserve legacy discovery
unchanged when the endpoint is disabled or unavailable.\n- Keep remote
plugin and connector app identities out of model-visible context and
attach them only to Codex-owned elicitation metadata.\n\nStack\n- 3/4,
based on #28400.\n- Endpoint client and cache: #28399.\n- Generalized
suggestion presentation: #28400.\n- Install-schema follow-up:
#28403.\n\nValidation\n- \n- \n- \n- \n- Full : 2,649 passed and 88
environment-dependent tests failed because this sandbox cannot write ,
nest Seatbelt, or locate auxiliary test binaries.

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

@@ -130,8 +130,8 @@ impl RequestPluginInstallHandler {
                     ToolSuggestPresentation::ListTool => format!(
                         "the discoverable tools returned by {LIST_AVAILABLE_PLUGINS_TO_INSTALL_TOOL_NAME}"
                     ),
-                    ToolSuggestPresentation::DeveloperContext => {
-                        "the developer recommendations".to_string()
+                    ToolSuggestPresentation::RecommendationContext => {
+                        "the <recommended_plugins> list".to_string()
                     }
                 };
                 FunctionCallError::RespondToModel(format!(

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

@@ -39,8 +39,8 @@ pub(crate) fn create_request_plugin_install_tool(
         ToolSuggestPresentation::ListTool => format!(
             "# Request plugin/connector install\n\nUse this tool only after `{LIST_AVAILABLE_PLUGINS_TO_INSTALL_TOOL_NAME}` returns a plugin or connector that exactly matches the user's explicit request.\n\nDo not use it for adjacent capabilities, broad recommendations, or tools that merely seem useful. Pass the returned `tool_type` through directly, and pass the returned `id` as `tool_id`.\n\nIMPORTANT: DO NOT call this tool in parallel with other tools."
         ),
-        ToolSuggestPresentation::DeveloperContext =>
-            "# Suggest a recommended plugin installation\n\nSuggest installing a plugin from the developer `<recommended_plugins>` list when it would help with the user's current request. Briefly explain why in `suggest_reason`.".to_string(),
+        ToolSuggestPresentation::RecommendationContext =>
+            "# Suggest a recommended plugin installation\n\nSuggest installing a plugin from the `<recommended_plugins>` list when it would help with the user's current request. Briefly explain why in `suggest_reason`.".to_string(),
     };
 
     ToolSpec::Function(ResponsesApiTool {
@@ -126,15 +126,15 @@ mod tests {
     }
 
     #[test]
-    fn developer_recommendations_change_only_the_description() {
+    fn recommendation_context_changes_only_the_description() {
         let mut expected = create_request_plugin_install_tool(ToolSuggestPresentation::ListTool);
         let recommendations =
-            create_request_plugin_install_tool(ToolSuggestPresentation::DeveloperContext);
+            create_request_plugin_install_tool(ToolSuggestPresentation::RecommendationContext);
 
         let ToolSpec::Function(expected_function) = &mut expected else {
             panic!("expected function tool specs");
         };
-        expected_function.description = "# Suggest a recommended plugin installation\n\nSuggest installing a plugin from the developer `<recommended_plugins>` list when it would help with the user's current request. Briefly explain why in `suggest_reason`.".to_string();
+        expected_function.description = "# Suggest a recommended plugin installation\n\nSuggest installing a plugin from the `<recommended_plugins>` list when it would help with the user's current request. Briefly explain why in `suggest_reason`.".to_string();
 
         assert_eq!(recommendations, expected);
     }

codex-rs/core/src/tools/router.rs

@@ -48,8 +48,7 @@ pub(crate) struct ToolRouterParams<'a> {
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub(crate) enum ToolSuggestPresentation {
     ListTool,
-    #[allow(dead_code)]
-    DeveloperContext,
+    RecommendationContext,
 }
 
 #[derive(Clone, Debug)]

codex-rs/core/src/tools/spec_plan_tests.rs

@@ -883,7 +883,7 @@ async fn request_plugin_install_requires_all_discovery_features() {
         None,
         Some(ToolSuggestCandidates {
             tools: Vec::new(),
-            presentation: ToolSuggestPresentation::DeveloperContext,
+            presentation: ToolSuggestPresentation::RecommendationContext,
         }),
     ] {
         let plan = probe_with(
@@ -959,7 +959,7 @@ async fn request_plugin_install_description_refers_to_recommended_plugins_hint()
         },
         ToolPlanInputs {
             tool_suggest_candidates: Some(plugin_candidates(
-                ToolSuggestPresentation::DeveloperContext,
+                ToolSuggestPresentation::RecommendationContext,
             )),
             ..ToolPlanInputs::default()
         },
@@ -973,7 +973,7 @@ async fn request_plugin_install_description_refers_to_recommended_plugins_hint()
     else {
         panic!("expected request_plugin_install function spec");
     };
-    assert!(request_description.contains("developer `<recommended_plugins>` list"));
+    assert!(request_description.contains("the `<recommended_plugins>` list"));
     assert!(!request_description.contains("list_available_plugins_to_install"));
     assert!(!request_description.contains("github"));
     plan.assert_visible_lacks(&["list_available_plugins_to_install"]);