Remove step-scoped data from extension contributors (#34734)

## What changed

- Remove the step-scoped `ExtensionData` argument from context, turn-input, and tool contributors.
- Pass the host's optional `McpResourceClient` through `ThreadStartInput` so extensions can retain session capabilities explicitly.
- Keep the MCP resource client in skills-owned session state for catalog loading and skill tools.

GitOrigin-RevId: bafa77bcd998aff408d6a396c5fd9ac268c4cce4

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

@@ -52,7 +52,6 @@ impl ContextContributor for MemoriesExtension {
         &'a self,
         _session_store: &'a ExtensionData,
         thread_store: &'a ExtensionData,
-        _step_store: &'a ExtensionData,
     ) -> std::pin::Pin<Box<dyn std::future::Future<Output = Vec<PromptFragment>> + Send + 'a>> {
         Box::pin(async move {
             let Some(config) = thread_store.get::<MemoriesExtensionConfig>() else {
@@ -101,7 +100,6 @@ impl ToolContributor for MemoriesExtension {
         &self,
         _session_store: &ExtensionData,
         thread_store: &ExtensionData,
-        _step_store: &ExtensionData,
     ) -> Vec<Arc<dyn codex_extension_api::ToolExecutor<codex_extension_api::ToolCall>>> {
         let Some(config) = thread_store.get::<MemoriesExtensionConfig>() else {
             return Vec::new();

codex-rs/ext/memories/src/tests.rs

@@ -42,7 +42,6 @@ fn tools_are_not_contributed_without_thread_config() {
             .tools(
                 &ExtensionData::new("session"),
                 &ExtensionData::new("thread"),
-                &ExtensionData::new("step")
             )
             .is_empty()
     );
@@ -60,11 +59,7 @@ fn tools_are_not_contributed_when_disabled() {
 
     assert!(
         extension
-            .tools(
-                &ExtensionData::new("session"),
-                &thread_store,
-                &ExtensionData::new("step"),
-            )
+            .tools(&ExtensionData::new("session"), &thread_store)
             .is_empty()
     );
 }
@@ -81,11 +76,7 @@ fn tools_are_not_contributed_when_dedicated_tools_disabled() {
 
     assert!(
         extension
-            .tools(
-                &ExtensionData::new("session"),
-                &thread_store,
-                &ExtensionData::new("step"),
-            )
+            .tools(&ExtensionData::new("session"), &thread_store)
             .is_empty()
     );
 }
@@ -101,11 +92,7 @@ fn tools_are_contributed_when_enabled_with_dedicated_tools() {
     });
 
     let tool_names = extension
-        .tools(
-            &ExtensionData::new("session"),
-            &thread_store,
-            &ExtensionData::new("step"),
-        )
+        .tools(&ExtensionData::new("session"), &thread_store)
         .into_iter()
         .map(|tool| tool.tool_name())
         .collect::<Vec<_>>();
@@ -136,13 +123,7 @@ fn install_registers_dedicated_tool_contributor() {
     let tool_names = registry
         .tool_contributors()
         .iter()
-        .flat_map(|contributor| {
-            contributor.tools(
-                &ExtensionData::new("session"),
-                &thread_store,
-                &ExtensionData::new("step"),
-            )
-        })
+        .flat_map(|contributor| contributor.tools(&ExtensionData::new("session"), &thread_store))
         .map(|tool| tool.tool_name())
         .collect::<Vec<_>>();
 
@@ -200,11 +181,7 @@ async fn prompt_contribution_uses_memory_summary_when_enabled() {
     });
 
     let fragments = extension
-        .contribute_thread_context(
-            &ExtensionData::new("session"),
-            &thread_store,
-            &ExtensionData::new("step"),
-        )
+        .contribute_thread_context(&ExtensionData::new("session"), &thread_store)
         .await;
 
     assert_eq!(fragments.len(), 1);