feat: drop CodexExtension (#22140)

Drop `CodexExtension` as not needed for now

codex-rs/app-server/src/extensions.rs

@@ -5,9 +5,7 @@ use codex_extension_api::ExtensionRegistry;
 use codex_extension_api::ExtensionRegistryBuilder;
 
 pub(crate) fn thread_extensions() -> Arc<ExtensionRegistry<Config>> {
-    Arc::new(
-        ExtensionRegistryBuilder::<Config>::new()
-            .with_extension(codex_git_attribution::extension())
-            .build(),
-    )
+    let mut builder = ExtensionRegistryBuilder::<Config>::new();
+    codex_git_attribution::install(&mut builder);
+    Arc::new(builder.build())
 }

codex-rs/ext/extension-api/examples/enabled_extensions.rs

@@ -1,29 +1,23 @@
 #[path = "enabled_extensions/shared_state_extension.rs"]
 mod shared_state_extension;
 
-use std::sync::Arc;
-
 use codex_extension_api::ExtensionData;
 use codex_extension_api::ExtensionRegistryBuilder;
-use shared_state_extension::SharedStateExtension;
 use shared_state_extension::recorded_style_contributions;
 use shared_state_extension::recorded_usage_contributions;
 
 fn main() {
-    // 1. Build the extension value owned by the host.
-    let extension = Arc::new(SharedStateExtension);
+    // 1. Install the contributors for the thread-start input type this host exposes.
+    let mut builder = ExtensionRegistryBuilder::<()>::new();
+    shared_state_extension::install(&mut builder);
+    let registry = builder.build();
 
-    // 2. Install it into the registry for the thread-start input type this host exposes.
-    let registry = ExtensionRegistryBuilder::<()>::new()
-        .with_extension(extension)
-        .build();
-
-    // 3. The host decides which stores are shared.
+    // 2. The host decides which stores are shared.
     let session_store = ExtensionData::new();
     let first_thread_store = ExtensionData::new();
     let second_thread_store = ExtensionData::new();
 
-    // 4. Reusing the same session store shares session state across threads.
+    // 3. Reusing the same session store shares session state across threads.
     let first_thread_fragments = contribute_prompt(&registry, &session_store, &first_thread_store);
     contribute_prompt(&registry, &session_store, &first_thread_store);
     contribute_prompt(&registry, &session_store, &second_thread_store);

codex-rs/ext/extension-api/examples/enabled_extensions/shared_state_extension.rs

@@ -2,21 +2,15 @@ use std::sync::Arc;
 use std::sync::atomic::AtomicU64;
 use std::sync::atomic::Ordering;
 
-use codex_extension_api::CodexExtension;
 use codex_extension_api::ContextContributor;
 use codex_extension_api::ExtensionData;
 use codex_extension_api::ExtensionRegistryBuilder;
 use codex_extension_api::PromptFragment;
 
-/// Small tutorial extension that installs two prompt contributors.
-#[derive(Debug, Default)]
-pub struct SharedStateExtension;
-
-impl CodexExtension<()> for SharedStateExtension {
-    fn install(self: Arc<Self>, registry: &mut ExtensionRegistryBuilder<()>) {
-        registry.prompt_contributor(Arc::new(StyleContributor));
-        registry.prompt_contributor(Arc::new(UsageContributor));
-    }
+/// Installs the tutorial contributors used by the example host.
+pub fn install(registry: &mut ExtensionRegistryBuilder<()>) {
+    registry.prompt_contributor(Arc::new(StyleContributor));
+    registry.prompt_contributor(Arc::new(UsageContributor));
 }
 
 #[derive(Debug)]

codex-rs/ext/extension-api/src/extension.rs

@@ -1,12 +0,0 @@
-use std::sync::Arc;
-
-use crate::ExtensionRegistryBuilder;
-
-/// First-party extension that can install one or more typed runtime contributions.
-///
-/// Implementations should use [`Self::install`] only to register the concrete
-/// providers they own.
-pub trait CodexExtension<C>: Send + Sync {
-    /// Registers this extension's concrete typed contributions.
-    fn install(self: Arc<Self>, registry: &mut ExtensionRegistryBuilder<C>);
-}

codex-rs/ext/extension-api/src/lib.rs

@@ -1,5 +1,4 @@
 mod contributors;
-mod extension;
 mod registry;
 mod state;
 
@@ -14,7 +13,6 @@ pub use contributors::ToolContributor;
 pub use contributors::ToolHandler;
 pub use contributors::TurnItemContributionFuture;
 pub use contributors::TurnItemContributor;
-pub use extension::CodexExtension;
 pub use registry::ExtensionRegistry;
 pub use registry::ExtensionRegistryBuilder;
 pub use registry::empty_extension_registry;

codex-rs/ext/extension-api/src/registry.rs

@@ -1,13 +1,12 @@
 use std::sync::Arc;
 
 use crate::ApprovalInterceptorContributor;
-use crate::CodexExtension;
 use crate::ContextContributor;
 use crate::ThreadStartContributor;
 use crate::ToolContributor;
 use crate::TurnItemContributor;
 
-/// Mutable registry used while extensions install their typed contributions.
+/// Mutable registry used while hosts register typed runtime contributions.
 pub struct ExtensionRegistryBuilder<C> {
     thread_start_contributors: Vec<Arc<dyn ThreadStartContributor<C>>>,
     context_contributors: Vec<Arc<dyn ContextContributor>>,
@@ -34,24 +33,6 @@ impl<C> ExtensionRegistryBuilder<C> {
         Self::default()
     }
 
-    /// Installs one extension and returns the builder.
-    #[must_use]
-    pub fn with_extension<E>(mut self, extension: Arc<E>) -> Self
-    where
-        E: CodexExtension<C> + 'static,
-    {
-        self.install_extension(extension);
-        self
-    }
-
-    /// Installs one extension into the registry under construction.
-    pub fn install_extension<E>(&mut self, extension: Arc<E>)
-    where
-        E: CodexExtension<C> + 'static,
-    {
-        extension.install(self);
-    }
-
     /// Registers one approval interceptor contributor.
     pub fn approval_interceptor_contributor(
         &mut self,
@@ -128,7 +109,7 @@ impl<C> ExtensionRegistry<C> {
     }
 }
 
-/// Creates an empty shared registry for hosts that do not install extensions.
+/// Creates an empty shared registry for hosts that do not register contributions.
 pub fn empty_extension_registry<C>() -> Arc<ExtensionRegistry<C>> {
     Arc::new(ExtensionRegistryBuilder::new().build())
 }

codex-rs/ext/git-attribution/src/lib.rs

@@ -1,7 +1,6 @@
 use std::sync::Arc;
 
 use codex_core::config::Config;
-use codex_extension_api::CodexExtension;
 use codex_extension_api::ContextContributor;
 use codex_extension_api::ExtensionData;
 use codex_extension_api::ExtensionRegistryBuilder;
@@ -11,17 +10,10 @@ use codex_features::Feature;
 
 const DEFAULT_ATTRIBUTION_VALUE: &str = "Codex <noreply@openai.com>";
 
-/// Prompt-only extension that contributes the configured git-attribution instruction.
+/// Contributes the configured git-attribution instruction.
 #[derive(Clone, Copy, Debug, Default)]
 pub struct GitAttributionExtension;
 
-impl GitAttributionExtension {
-    /// Creates an extension instance.
-    pub fn new() -> Self {
-        Self
-    }
-}
-
 impl ContextContributor for GitAttributionExtension {
     fn contribute(
         &self,
@@ -61,16 +53,11 @@ impl ThreadStartContributor<Config> for GitAttributionExtension {
     }
 }
 
-impl CodexExtension<Config> for GitAttributionExtension {
-    fn install(self: Arc<Self>, registry: &mut ExtensionRegistryBuilder<Config>) {
-        registry.thread_start_contributor(self.clone());
-        registry.prompt_contributor(self);
-    }
-}
-
-/// Creates a shared git-attribution extension instance.
-pub fn extension() -> Arc<GitAttributionExtension> {
-    Arc::new(GitAttributionExtension::new())
+/// Installs the git-attribution contributors into the extension registry.
+pub fn install(registry: &mut ExtensionRegistryBuilder<Config>) {
+    let extension = Arc::new(GitAttributionExtension);
+    registry.thread_start_contributor(extension.clone());
+    registry.prompt_contributor(extension);
 }
 
 fn build_commit_message_trailer(config_attribution: Option<&str>) -> Option<String> {