diff --git a/codex-rs/Cargo.lock b/codex-rs/Cargo.lock
index 17b2696cbf5..51a6cd08cc6 100644
--- a/codex-rs/Cargo.lock
+++ b/codex-rs/Cargo.lock
@@ -3047,7 +3047,6 @@ name = "codex-goal-extension"
 version = "0.0.0"
 dependencies = [
  "anyhow",
- "async-trait",
  "chrono",
  "codex-analytics",
  "codex-core",
@@ -3101,7 +3100,6 @@ dependencies = [
 name = "codex-image-generation-extension"
 version = "0.0.0"
 dependencies = [
- "async-trait",
  "codex-api",
  "codex-core",
  "codex-extension-api",
@@ -3301,7 +3299,6 @@ dependencies = [
 name = "codex-memories-extension"
 version = "0.0.0"
 dependencies = [
- "async-trait",
  "codex-core",
  "codex-extension-api",
  "codex-features",
@@ -3916,7 +3913,6 @@ dependencies = [
 name = "codex-tools"
 version = "0.0.0"
 dependencies = [
- "async-trait",
  "codex-app-server-protocol",
  "codex-code-mode",
  "codex-features",
@@ -4297,7 +4293,6 @@ dependencies = [
 name = "codex-web-search-extension"
 version = "0.0.0"
 dependencies = [
- "async-trait",
  "codex-api",
  "codex-core",
  "codex-extension-api",
diff --git a/codex-rs/core/src/tools/code_mode/execute_handler.rs b/codex-rs/core/src/tools/code_mode/execute_handler.rs
index 0bdb8b20a6e..2e46c1bd6b9 100644
--- a/codex-rs/core/src/tools/code_mode/execute_handler.rs
+++ b/codex-rs/core/src/tools/code_mode/execute_handler.rs
@@ -91,7 +91,6 @@ impl CodeModeExecuteHandler {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for CodeModeExecuteHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain(PUBLIC_TOOL_NAME)
@@ -101,11 +100,8 @@ impl ToolExecutor<ToolInvocation> for CodeModeExecuteHandler {
         self.spec.clone()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/code_mode/wait_handler.rs b/codex-rs/core/src/tools/code_mode/wait_handler.rs
index c1928955f4a..953391a573c 100644
--- a/codex-rs/core/src/tools/code_mode/wait_handler.rs
+++ b/codex-rs/core/src/tools/code_mode/wait_handler.rs
@@ -44,7 +44,6 @@ where
     })
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for CodeModeWaitHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain(WAIT_TOOL_NAME)
@@ -54,11 +53,8 @@ impl ToolExecutor<ToolInvocation> for CodeModeWaitHandler {
         create_wait_tool()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/agent_jobs/report_agent_job_result.rs b/codex-rs/core/src/tools/handlers/agent_jobs/report_agent_job_result.rs
index 5f2a6153295..579cc25ffb7 100644
--- a/codex-rs/core/src/tools/handlers/agent_jobs/report_agent_job_result.rs
+++ b/codex-rs/core/src/tools/handlers/agent_jobs/report_agent_job_result.rs
@@ -13,7 +13,6 @@ use super::*;
 
 pub struct ReportAgentJobResultHandler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for ReportAgentJobResultHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("report_agent_job_result")
@@ -23,11 +22,8 @@ impl ToolExecutor<ToolInvocation> for ReportAgentJobResultHandler {
         create_report_agent_job_result_tool()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/agent_jobs/spawn_agents_on_csv.rs b/codex-rs/core/src/tools/handlers/agent_jobs/spawn_agents_on_csv.rs
index 16e1b1f72c8..6da517b9cc5 100644
--- a/codex-rs/core/src/tools/handlers/agent_jobs/spawn_agents_on_csv.rs
+++ b/codex-rs/core/src/tools/handlers/agent_jobs/spawn_agents_on_csv.rs
@@ -14,7 +14,6 @@ use super::*;
 
 pub struct SpawnAgentsOnCsvHandler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for SpawnAgentsOnCsvHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("spawn_agents_on_csv")
@@ -24,11 +23,8 @@ impl ToolExecutor<ToolInvocation> for SpawnAgentsOnCsvHandler {
         create_spawn_agents_on_csv_tool()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/apply_patch.rs b/codex-rs/core/src/tools/handlers/apply_patch.rs
index 6a322ed6aea..70452b6657e 100644
--- a/codex-rs/core/src/tools/handlers/apply_patch.rs
+++ b/codex-rs/core/src/tools/handlers/apply_patch.rs
@@ -305,7 +305,6 @@ async fn effective_patch_permissions(
     )
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for ApplyPatchHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("apply_patch")
@@ -315,11 +314,8 @@ impl ToolExecutor<ToolInvocation> for ApplyPatchHandler {
         create_apply_patch_freeform_tool(self.multi_environment)
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/dynamic.rs b/codex-rs/core/src/tools/handlers/dynamic.rs
index e0151cf1896..dabcea8e5af 100644
--- a/codex-rs/core/src/tools/handlers/dynamic.rs
+++ b/codex-rs/core/src/tools/handlers/dynamic.rs
@@ -61,7 +61,6 @@ impl DynamicToolHandler {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for DynamicToolHandler {
     fn tool_name(&self) -> ToolName {
         self.tool_name.clone()
@@ -86,11 +85,8 @@ impl ToolExecutor<ToolInvocation> for DynamicToolHandler {
         )
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/extension_tools.rs b/codex-rs/core/src/tools/handlers/extension_tools.rs
index a94c764a9f7..d429b6c1fc0 100644
--- a/codex-rs/core/src/tools/handlers/extension_tools.rs
+++ b/codex-rs/core/src/tools/handlers/extension_tools.rs
@@ -11,13 +11,11 @@ use codex_tools::ToolSpec;
 use codex_tools::TurnItemEmissionFuture;
 use codex_tools::TurnItemEmitter;
 
-use crate::function_tool::FunctionCallError;
 use crate::session::session::Session;
 use crate::session::turn_context::TurnContext;
 use crate::stream_events_utils::TurnItemContributorPolicy;
 use crate::stream_events_utils::finalize_turn_item;
 use crate::tools::context::ToolInvocation;
-use crate::tools::context::ToolOutput;
 use crate::tools::context::ToolPayload;
 use crate::tools::registry::CoreToolRuntime;
 use crate::tools::registry::ToolExecutor;
@@ -30,7 +28,6 @@ impl ExtensionToolAdapter {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for ExtensionToolAdapter {
     fn tool_name(&self) -> ToolName {
         self.0.tool_name()
@@ -52,11 +49,8 @@ impl ToolExecutor<ToolInvocation> for ExtensionToolAdapter {
         self.0.search_info()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn ToolOutput>, FunctionCallError> {
-        self.0.handle(to_extension_call(&invocation).await).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(async move { self.0.handle(to_extension_call(&invocation).await).await })
     }
 }
 
@@ -162,7 +156,6 @@ mod tests {
 
     struct StubExtensionExecutor;
 
-    #[async_trait::async_trait]
     impl codex_extension_api::ToolExecutor<codex_tools::ToolCall> for StubExtensionExecutor {
         fn tool_name(&self) -> codex_tools::ToolName {
             codex_tools::ToolName::plain("extension_echo")
@@ -187,13 +180,13 @@ mod tests {
             })
         }
 
-        async fn handle(
-            &self,
-            _call: codex_tools::ToolCall,
-        ) -> Result<Box<dyn codex_tools::ToolOutput>, codex_tools::FunctionCallError> {
-            Ok(Box::new(codex_tools::JsonToolOutput::new(
-                json!({ "ok": true }),
-            )))
+        fn handle(&self, _call: codex_tools::ToolCall) -> codex_tools::ToolExecutorFuture<'_> {
+            Box::pin(async {
+                Ok(
+                    Box::new(codex_tools::JsonToolOutput::new(json!({ "ok": true })))
+                        as Box<dyn codex_tools::ToolOutput>,
+                )
+            })
         }
     }
 
@@ -201,7 +194,6 @@ mod tests {
         captured_call: Arc<Mutex<Option<codex_tools::ToolCall>>>,
     }
 
-    #[async_trait::async_trait]
     impl codex_extension_api::ToolExecutor<codex_tools::ToolCall> for CapturingExtensionExecutor {
         fn tool_name(&self) -> codex_tools::ToolName {
             codex_tools::ToolName::plain("extension_echo")
@@ -218,11 +210,8 @@ mod tests {
             })
         }
 
-        async fn handle(
-            &self,
-            call: codex_tools::ToolCall,
-        ) -> Result<Box<dyn codex_tools::ToolOutput>, codex_tools::FunctionCallError> {
-            self.handle_call(call).await
+        fn handle(&self, call: codex_tools::ToolCall) -> codex_tools::ToolExecutorFuture<'_> {
+            Box::pin(self.handle_call(call))
         }
     }
 
@@ -242,9 +231,10 @@ mod tests {
             call.turn_item_emitter.emit_started(item.clone()).await;
             call.turn_item_emitter.emit_completed(item).await;
             *self.captured_call.lock().await = Some(call);
-            Ok(Box::new(codex_tools::JsonToolOutput::new(
-                json!({ "ok": true }),
-            )))
+            Ok(
+                Box::new(codex_tools::JsonToolOutput::new(json!({ "ok": true })))
+                    as Box<dyn codex_tools::ToolOutput>,
+            )
         }
     }
 
@@ -441,7 +431,6 @@ mod tests {
         );
     }
 
-    #[async_trait::async_trait]
     impl codex_extension_api::ToolExecutor<codex_tools::ToolCall> for ImageGenerationExtensionExecutor {
         fn tool_name(&self) -> codex_tools::ToolName {
             codex_tools::ToolName::namespaced("image_gen", "imagegen")
@@ -458,11 +447,8 @@ mod tests {
             })
         }
 
-        async fn handle(
-            &self,
-            call: codex_tools::ToolCall,
-        ) -> Result<Box<dyn codex_tools::ToolOutput>, codex_tools::FunctionCallError> {
-            self.handle_call(call).await
+        fn handle(&self, call: codex_tools::ToolCall) -> codex_tools::ToolExecutorFuture<'_> {
+            Box::pin(self.handle_call(call))
         }
     }
 
@@ -493,9 +479,10 @@ mod tests {
                     },
                 ))
                 .await;
-            Ok(Box::new(codex_tools::JsonToolOutput::new(
-                json!({ "ok": true }),
-            )))
+            Ok(
+                Box::new(codex_tools::JsonToolOutput::new(json!({ "ok": true })))
+                    as Box<dyn codex_tools::ToolOutput>,
+            )
         }
     }
 
diff --git a/codex-rs/core/src/tools/handlers/list_available_plugins_to_install.rs b/codex-rs/core/src/tools/handlers/list_available_plugins_to_install.rs
index 2b782e4552f..766b0e9b753 100644
--- a/codex-rs/core/src/tools/handlers/list_available_plugins_to_install.rs
+++ b/codex-rs/core/src/tools/handlers/list_available_plugins_to_install.rs
@@ -54,7 +54,6 @@ impl ListAvailablePluginsToInstallHandler {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for ListAvailablePluginsToInstallHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain(LIST_AVAILABLE_PLUGINS_TO_INSTALL_TOOL_NAME)
@@ -68,11 +67,8 @@ impl ToolExecutor<ToolInvocation> for ListAvailablePluginsToInstallHandler {
         false
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/mcp.rs b/codex-rs/core/src/tools/handlers/mcp.rs
index d60cdfdd0cf..efb32aab945 100644
--- a/codex-rs/core/src/tools/handlers/mcp.rs
+++ b/codex-rs/core/src/tools/handlers/mcp.rs
@@ -64,7 +64,6 @@ fn ensure_mcp_prefix(name: &str) -> String {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for McpHandler {
     fn tool_name(&self) -> ToolName {
         self.tool_info.canonical_tool_name()
@@ -113,11 +112,8 @@ impl ToolExecutor<ToolInvocation> for McpHandler {
         )
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/mcp_resource/list_mcp_resource_templates.rs b/codex-rs/core/src/tools/handlers/mcp_resource/list_mcp_resource_templates.rs
index 8974d678fdd..80b183dabab 100644
--- a/codex-rs/core/src/tools/handlers/mcp_resource/list_mcp_resource_templates.rs
+++ b/codex-rs/core/src/tools/handlers/mcp_resource/list_mcp_resource_templates.rs
@@ -26,7 +26,6 @@ use super::serialize_function_output;
 
 pub struct ListMcpResourceTemplatesHandler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for ListMcpResourceTemplatesHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("list_mcp_resource_templates")
@@ -40,11 +39,8 @@ impl ToolExecutor<ToolInvocation> for ListMcpResourceTemplatesHandler {
         true
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/mcp_resource/list_mcp_resources.rs b/codex-rs/core/src/tools/handlers/mcp_resource/list_mcp_resources.rs
index f3a7b43c28b..a77d617b942 100644
--- a/codex-rs/core/src/tools/handlers/mcp_resource/list_mcp_resources.rs
+++ b/codex-rs/core/src/tools/handlers/mcp_resource/list_mcp_resources.rs
@@ -26,7 +26,6 @@ use super::serialize_function_output;
 
 pub struct ListMcpResourcesHandler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for ListMcpResourcesHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("list_mcp_resources")
@@ -40,11 +39,8 @@ impl ToolExecutor<ToolInvocation> for ListMcpResourcesHandler {
         true
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/mcp_resource/read_mcp_resource.rs b/codex-rs/core/src/tools/handlers/mcp_resource/read_mcp_resource.rs
index 9861e5d22d6..9ca15718a0c 100644
--- a/codex-rs/core/src/tools/handlers/mcp_resource/read_mcp_resource.rs
+++ b/codex-rs/core/src/tools/handlers/mcp_resource/read_mcp_resource.rs
@@ -26,7 +26,6 @@ use super::serialize_function_output;
 
 pub struct ReadMcpResourceHandler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for ReadMcpResourceHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("read_mcp_resource")
@@ -40,11 +39,8 @@ impl ToolExecutor<ToolInvocation> for ReadMcpResourceHandler {
         true
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/multi_agents/close_agent.rs b/codex-rs/core/src/tools/handlers/multi_agents/close_agent.rs
index 0d4e17447dc..d1017adb65c 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents/close_agent.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents/close_agent.rs
@@ -6,7 +6,6 @@ use codex_tools::ToolSpec;
 
 pub(crate) struct Handler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for Handler {
     fn tool_name(&self) -> ToolName {
         ToolName::namespaced(MULTI_AGENT_V1_NAMESPACE, "close_agent")
@@ -23,11 +22,8 @@ impl ToolExecutor<ToolInvocation> for Handler {
         )
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        handle_close_agent(invocation).await.map(boxed_tool_output)
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(async move { handle_close_agent(invocation).await.map(boxed_tool_output) })
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/multi_agents/resume_agent.rs b/codex-rs/core/src/tools/handlers/multi_agents/resume_agent.rs
index 8f95abe4e31..fa464ddbbb2 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents/resume_agent.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents/resume_agent.rs
@@ -7,7 +7,6 @@ use std::sync::Arc;
 
 pub(crate) struct Handler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for Handler {
     fn tool_name(&self) -> ToolName {
         ToolName::namespaced(MULTI_AGENT_V1_NAMESPACE, "resume_agent")
@@ -24,11 +23,8 @@ impl ToolExecutor<ToolInvocation> for Handler {
         )
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        handle_resume_agent(invocation).await.map(boxed_tool_output)
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(async move { handle_resume_agent(invocation).await.map(boxed_tool_output) })
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/multi_agents/send_input.rs b/codex-rs/core/src/tools/handlers/multi_agents/send_input.rs
index b811faf91a6..375bb50ac7c 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents/send_input.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents/send_input.rs
@@ -6,7 +6,6 @@ use codex_tools::ToolSpec;
 
 pub(crate) struct Handler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for Handler {
     fn tool_name(&self) -> ToolName {
         ToolName::namespaced(MULTI_AGENT_V1_NAMESPACE, "send_input")
@@ -23,11 +22,8 @@ impl ToolExecutor<ToolInvocation> for Handler {
         )
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/multi_agents/spawn.rs b/codex-rs/core/src/tools/handlers/multi_agents/spawn.rs
index 3f6c97fcbcb..204385934e2 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents/spawn.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents/spawn.rs
@@ -22,7 +22,6 @@ impl Handler {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for Handler {
     fn tool_name(&self) -> ToolName {
         ToolName::namespaced(MULTI_AGENT_V1_NAMESPACE, "spawn_agent")
@@ -39,11 +38,8 @@ impl ToolExecutor<ToolInvocation> for Handler {
         )
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        handle_spawn_agent(invocation).await.map(boxed_tool_output)
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(async move { handle_spawn_agent(invocation).await.map(boxed_tool_output) })
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/multi_agents/wait.rs b/codex-rs/core/src/tools/handlers/multi_agents/wait.rs
index 1f6b7db8f10..be22b369082 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents/wait.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents/wait.rs
@@ -27,7 +27,6 @@ impl Handler {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for Handler {
     fn tool_name(&self) -> ToolName {
         ToolName::namespaced(MULTI_AGENT_V1_NAMESPACE, "wait_agent")
@@ -44,11 +43,8 @@ impl ToolExecutor<ToolInvocation> for Handler {
         )
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/multi_agents_v2/followup_task.rs b/codex-rs/core/src/tools/handlers/multi_agents_v2/followup_task.rs
index 66a39cc79d0..bd4dafe7c26 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents_v2/followup_task.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents_v2/followup_task.rs
@@ -7,7 +7,6 @@ use codex_tools::ToolSpec;
 
 pub(crate) struct Handler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for Handler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("followup_task")
@@ -17,11 +16,8 @@ impl ToolExecutor<ToolInvocation> for Handler {
         create_followup_task_tool()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/multi_agents_v2/interrupt_agent.rs b/codex-rs/core/src/tools/handlers/multi_agents_v2/interrupt_agent.rs
index 159c49127a8..aeed055b4ef 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents_v2/interrupt_agent.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents_v2/interrupt_agent.rs
@@ -6,7 +6,6 @@ use codex_tools::ToolSpec;
 
 pub(crate) struct Handler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for Handler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("interrupt_agent")
@@ -16,13 +15,12 @@ impl ToolExecutor<ToolInvocation> for Handler {
         create_interrupt_agent_tool_v2()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        handle_interrupt_agent(invocation)
-            .await
-            .map(boxed_tool_output)
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(async move {
+            handle_interrupt_agent(invocation)
+                .await
+                .map(boxed_tool_output)
+        })
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/multi_agents_v2/list_agents.rs b/codex-rs/core/src/tools/handlers/multi_agents_v2/list_agents.rs
index 18421278fe0..99e54e1ce91 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents_v2/list_agents.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents_v2/list_agents.rs
@@ -5,7 +5,6 @@ use codex_tools::ToolSpec;
 
 pub(crate) struct Handler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for Handler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("list_agents")
@@ -15,11 +14,8 @@ impl ToolExecutor<ToolInvocation> for Handler {
         create_list_agents_tool()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/multi_agents_v2/send_message.rs b/codex-rs/core/src/tools/handlers/multi_agents_v2/send_message.rs
index 2fd636a85c5..717e3bc9203 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents_v2/send_message.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents_v2/send_message.rs
@@ -7,7 +7,6 @@ use codex_tools::ToolSpec;
 
 pub(crate) struct Handler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for Handler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("send_message")
@@ -17,11 +16,8 @@ impl ToolExecutor<ToolInvocation> for Handler {
         create_send_message_tool()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/multi_agents_v2/spawn.rs b/codex-rs/core/src/tools/handlers/multi_agents_v2/spawn.rs
index 34fddc60b4e..2186a4a6d60 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents_v2/spawn.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents_v2/spawn.rs
@@ -22,7 +22,6 @@ impl Handler {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for Handler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("spawn_agent")
@@ -32,11 +31,8 @@ impl ToolExecutor<ToolInvocation> for Handler {
         create_spawn_agent_tool_v2(self.options.clone())
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        handle_spawn_agent(invocation).await.map(boxed_tool_output)
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(async move { handle_spawn_agent(invocation).await.map(boxed_tool_output) })
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/multi_agents_v2/wait.rs b/codex-rs/core/src/tools/handlers/multi_agents_v2/wait.rs
index 9d671b1989a..36e5aa24f68 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents_v2/wait.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents_v2/wait.rs
@@ -19,7 +19,6 @@ impl Handler {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for Handler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("wait_agent")
@@ -29,11 +28,8 @@ impl ToolExecutor<ToolInvocation> for Handler {
         create_wait_agent_tool_v2(self.options)
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/plan.rs b/codex-rs/core/src/tools/handlers/plan.rs
index ff18a328131..1b30c281ce2 100644
--- a/codex-rs/core/src/tools/handlers/plan.rs
+++ b/codex-rs/core/src/tools/handlers/plan.rs
@@ -45,7 +45,6 @@ impl ToolOutput for PlanToolOutput {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for PlanHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("update_plan")
@@ -55,11 +54,8 @@ impl ToolExecutor<ToolInvocation> for PlanHandler {
         create_update_plan_tool()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/request_permissions.rs b/codex-rs/core/src/tools/handlers/request_permissions.rs
index 7c24f15697a..4faf9d328b3 100644
--- a/codex-rs/core/src/tools/handlers/request_permissions.rs
+++ b/codex-rs/core/src/tools/handlers/request_permissions.rs
@@ -25,7 +25,6 @@ struct RequestPermissionsEnvironmentArgs {
     environment_id: Option<String>,
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for RequestPermissionsHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("request_permissions")
@@ -35,11 +34,8 @@ impl ToolExecutor<ToolInvocation> for RequestPermissionsHandler {
         create_request_permissions_tool(request_permissions_tool_description())
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/request_plugin_install.rs b/codex-rs/core/src/tools/handlers/request_plugin_install.rs
index 64625aaac0d..801031348f3 100644
--- a/codex-rs/core/src/tools/handlers/request_plugin_install.rs
+++ b/codex-rs/core/src/tools/handlers/request_plugin_install.rs
@@ -48,7 +48,6 @@ impl RequestPluginInstallHandler {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for RequestPluginInstallHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain(REQUEST_PLUGIN_INSTALL_TOOL_NAME)
@@ -62,11 +61,8 @@ impl ToolExecutor<ToolInvocation> for RequestPluginInstallHandler {
         true
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/request_user_input.rs b/codex-rs/core/src/tools/handlers/request_user_input.rs
index 3f3adf0ba39..4f26865a687 100644
--- a/codex-rs/core/src/tools/handlers/request_user_input.rs
+++ b/codex-rs/core/src/tools/handlers/request_user_input.rs
@@ -20,7 +20,6 @@ pub struct RequestUserInputHandler {
     pub available_modes: Vec<ModeKind>,
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for RequestUserInputHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain(REQUEST_USER_INPUT_TOOL_NAME)
@@ -30,11 +29,8 @@ impl ToolExecutor<ToolInvocation> for RequestUserInputHandler {
         create_request_user_input_tool(request_user_input_tool_description(&self.available_modes))
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/shell/shell_command.rs b/codex-rs/core/src/tools/handlers/shell/shell_command.rs
index e9fcf82046d..b754187d4ac 100644
--- a/codex-rs/core/src/tools/handlers/shell/shell_command.rs
+++ b/codex-rs/core/src/tools/handlers/shell/shell_command.rs
@@ -124,7 +124,6 @@ impl From<ShellCommandBackendConfig> for ShellCommandHandler {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for ShellCommandHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("shell_command")
@@ -141,11 +140,8 @@ impl ToolExecutor<ToolInvocation> for ShellCommandHandler {
         true
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/test_sync.rs b/codex-rs/core/src/tools/handlers/test_sync.rs
index 802859c916c..08d983b6160 100644
--- a/codex-rs/core/src/tools/handlers/test_sync.rs
+++ b/codex-rs/core/src/tools/handlers/test_sync.rs
@@ -57,7 +57,6 @@ fn barrier_map() -> &'static tokio::sync::Mutex<HashMap<String, BarrierState>> {
     BARRIERS.get_or_init(|| tokio::sync::Mutex::new(HashMap::new()))
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for TestSyncHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("test_sync_tool")
@@ -71,11 +70,8 @@ impl ToolExecutor<ToolInvocation> for TestSyncHandler {
         true
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/tool_search.rs b/codex-rs/core/src/tools/handlers/tool_search.rs
index a4781e75e21..9254f4bee07 100644
--- a/codex-rs/core/src/tools/handlers/tool_search.rs
+++ b/codex-rs/core/src/tools/handlers/tool_search.rs
@@ -53,7 +53,6 @@ impl ToolSearchHandler {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for ToolSearchHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain(TOOL_SEARCH_TOOL_NAME)
@@ -67,11 +66,8 @@ impl ToolExecutor<ToolInvocation> for ToolSearchHandler {
         true
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/unified_exec/exec_command.rs b/codex-rs/core/src/tools/handlers/unified_exec/exec_command.rs
index 9fe3b343b57..7c914deb4f5 100644
--- a/codex-rs/core/src/tools/handlers/unified_exec/exec_command.rs
+++ b/codex-rs/core/src/tools/handlers/unified_exec/exec_command.rs
@@ -71,7 +71,6 @@ impl ExecCommandHandler {
     }
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for ExecCommandHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("exec_command")
@@ -92,11 +91,8 @@ impl ToolExecutor<ToolInvocation> for ExecCommandHandler {
         true
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/unified_exec/write_stdin.rs b/codex-rs/core/src/tools/handlers/unified_exec/write_stdin.rs
index 9b319d54336..8ddce658402 100644
--- a/codex-rs/core/src/tools/handlers/unified_exec/write_stdin.rs
+++ b/codex-rs/core/src/tools/handlers/unified_exec/write_stdin.rs
@@ -31,7 +31,6 @@ struct WriteStdinArgs {
 
 pub struct WriteStdinHandler;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for WriteStdinHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("write_stdin")
@@ -41,11 +40,8 @@ impl ToolExecutor<ToolInvocation> for WriteStdinHandler {
         create_write_stdin_tool()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/handlers/view_image.rs b/codex-rs/core/src/tools/handlers/view_image.rs
index eb761359a7a..0432ad338fa 100644
--- a/codex-rs/core/src/tools/handlers/view_image.rs
+++ b/codex-rs/core/src/tools/handlers/view_image.rs
@@ -64,7 +64,6 @@ enum ViewImageDetail {
     Original,
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for ViewImageHandler {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("view_image")
@@ -78,11 +77,8 @@ impl ToolExecutor<ToolInvocation> for ViewImageHandler {
         true
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(invocation))
     }
 }
 
diff --git a/codex-rs/core/src/tools/parallel.rs b/codex-rs/core/src/tools/parallel.rs
index a6f630a342c..c40886b56cb 100644
--- a/codex-rs/core/src/tools/parallel.rs
+++ b/codex-rs/core/src/tools/parallel.rs
@@ -257,7 +257,6 @@ mod tests {
         tool_name: codex_tools::ToolName,
     }
 
-    #[async_trait::async_trait]
     impl ToolExecutor<ToolInvocation> for ImmediateHandler {
         fn tool_name(&self) -> codex_tools::ToolName {
             self.tool_name.clone()
@@ -274,14 +273,13 @@ mod tests {
             })
         }
 
-        async fn handle(
-            &self,
-            _invocation: ToolInvocation,
-        ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-            Ok(Box::new(FunctionToolOutput::from_text(
-                "ok".to_string(),
-                Some(true),
-            )))
+        fn handle(&self, _invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+            Box::pin(async {
+                Ok(
+                    Box::new(FunctionToolOutput::from_text("ok".to_string(), Some(true)))
+                        as Box<dyn crate::tools::context::ToolOutput>,
+                )
+            })
         }
     }
 
@@ -294,7 +292,6 @@ mod tests {
         allow_cleanup: Arc<Notify>,
     }
 
-    #[async_trait::async_trait]
     impl ToolExecutor<ToolInvocation> for CancellationCleanupHandler {
         fn tool_name(&self) -> codex_tools::ToolName {
             self.tool_name.clone()
@@ -311,11 +308,8 @@ mod tests {
             })
         }
 
-        async fn handle(
-            &self,
-            invocation: ToolInvocation,
-        ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-            self.handle_call(invocation).await
+        fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+            Box::pin(self.handle_call(invocation))
         }
     }
 
@@ -345,7 +339,7 @@ mod tests {
             Ok(Box::new(FunctionToolOutput::from_text(
                 "cleanup complete".to_string(),
                 Some(false),
-            )))
+            )) as Box<dyn crate::tools::context::ToolOutput>)
         }
     }
 
diff --git a/codex-rs/core/src/tools/registry.rs b/codex-rs/core/src/tools/registry.rs
index 20e08e9f7da..76e3f5f3414 100644
--- a/codex-rs/core/src/tools/registry.rs
+++ b/codex-rs/core/src/tools/registry.rs
@@ -250,7 +250,6 @@ struct ExposureOverride {
     exposure: ToolExposure,
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for ExposureOverride {
     fn tool_name(&self) -> ToolName {
         self.handler.tool_name()
@@ -272,11 +271,8 @@ impl ToolExecutor<ToolInvocation> for ExposureOverride {
         self.handler.search_info()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn ToolOutput>, FunctionCallError> {
-        self.handler.handle(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        self.handler.handle(invocation)
     }
 }
 
diff --git a/codex-rs/core/src/tools/registry_tests.rs b/codex-rs/core/src/tools/registry_tests.rs
index cc7f39e2a39..67613f1d081 100644
--- a/codex-rs/core/src/tools/registry_tests.rs
+++ b/codex-rs/core/src/tools/registry_tests.rs
@@ -5,7 +5,6 @@ struct TestHandler {
     tool_name: codex_tools::ToolName,
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for TestHandler {
     fn tool_name(&self) -> codex_tools::ToolName {
         self.tool_name.clone()
@@ -15,13 +14,15 @@ impl ToolExecutor<ToolInvocation> for TestHandler {
         test_spec(&self.tool_name)
     }
 
-    async fn handle(
-        &self,
-        _invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        Ok(Box::new(
-            crate::tools::context::FunctionToolOutput::from_text("ok".to_string(), Some(true)),
-        ))
+    fn handle(&self, _invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(async {
+            Ok(
+                Box::new(crate::tools::context::FunctionToolOutput::from_text(
+                    "ok".to_string(),
+                    Some(true),
+                )) as Box<dyn crate::tools::context::ToolOutput>,
+            )
+        })
     }
 }
 
@@ -38,7 +39,6 @@ struct LifecycleTestHandler {
     result: LifecycleTestResult,
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for LifecycleTestHandler {
     fn tool_name(&self) -> codex_tools::ToolName {
         self.tool_name.clone()
@@ -48,11 +48,8 @@ impl ToolExecutor<ToolInvocation> for LifecycleTestHandler {
         test_spec(&self.tool_name)
     }
 
-    async fn handle(
-        &self,
-        _invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        self.handle_call().await
+    fn handle(&self, _invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call())
     }
 }
 
@@ -66,7 +63,8 @@ impl LifecycleTestHandler {
                     "ok".to_string(),
                     Some(success),
                 ),
-            )),
+            )
+                as Box<dyn crate::tools::context::ToolOutput>),
             LifecycleTestResult::Err => Err(FunctionCallError::RespondToModel(
                 "handler failed".to_string(),
             )),
diff --git a/codex-rs/core/src/tools/router_tests.rs b/codex-rs/core/src/tools/router_tests.rs
index a9a52ca463c..4024cb61f73 100644
--- a/codex-rs/core/src/tools/router_tests.rs
+++ b/codex-rs/core/src/tools/router_tests.rs
@@ -44,7 +44,6 @@ impl codex_extension_api::ToolContributor for ExtensionEchoContributor {
 
 struct ExtensionEchoExecutor;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ExtensionToolCall> for ExtensionEchoExecutor {
     fn tool_name(&self) -> ToolName {
         ToolName::namespaced("extension/", "echo")
@@ -73,11 +72,8 @@ impl ToolExecutor<ExtensionToolCall> for ExtensionEchoExecutor {
         })
     }
 
-    async fn handle(
-        &self,
-        call: ExtensionToolCall,
-    ) -> Result<Box<dyn codex_tools::ToolOutput>, codex_tools::FunctionCallError> {
-        self.handle_call(call).await
+    fn handle(&self, call: ExtensionToolCall) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(call))
     }
 }
 
@@ -93,7 +89,7 @@ impl ExtensionEchoExecutor {
             "callId": call.call_id,
             "conversationHistory": call.conversation_history.items(),
             "ok": true,
-        }))))
+        }))) as Box<dyn codex_tools::ToolOutput>)
     }
 }
 
diff --git a/codex-rs/core/src/tools/spec_plan.rs b/codex-rs/core/src/tools/spec_plan.rs
index 19f4c9f8976..697eba1d4a1 100644
--- a/codex-rs/core/src/tools/spec_plan.rs
+++ b/codex-rs/core/src/tools/spec_plan.rs
@@ -72,7 +72,6 @@ use codex_tools::ToolCall as ExtensionToolCall;
 use codex_tools::ToolEnvironmentMode;
 use codex_tools::ToolExecutor;
 use codex_tools::ToolName;
-use codex_tools::ToolOutput;
 use codex_tools::ToolSearchInfo;
 use codex_tools::ToolSpec;
 use codex_tools::UnifiedExecShellMode;
@@ -946,7 +945,6 @@ struct MultiAgentV2NamespaceOverride {
     namespace: String,
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for MultiAgentV2NamespaceOverride {
     fn tool_name(&self) -> ToolName {
         ToolName::namespaced(self.namespace.clone(), self.handler.tool_name().name)
@@ -975,11 +973,8 @@ impl ToolExecutor<ToolInvocation> for MultiAgentV2NamespaceOverride {
         self.handler.search_info()
     }
 
-    async fn handle(
-        &self,
-        invocation: ToolInvocation,
-    ) -> Result<Box<dyn ToolOutput>, codex_tools::FunctionCallError> {
-        self.handler.handle(invocation).await
+    fn handle(&self, invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        self.handler.handle(invocation)
     }
 }
 
diff --git a/codex-rs/core/src/tools/spec_plan_tests.rs b/codex-rs/core/src/tools/spec_plan_tests.rs
index f96f41f0f25..a9eb5012d52 100644
--- a/codex-rs/core/src/tools/spec_plan_tests.rs
+++ b/codex-rs/core/src/tools/spec_plan_tests.rs
@@ -285,7 +285,6 @@ fn use_bedrock_provider(turn: &mut TurnContext) {
 
 struct WebRunExtensionTool;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ExtensionToolCall> for WebRunExtensionTool {
     fn tool_name(&self) -> ToolName {
         ToolName::namespaced("web", "run")
@@ -306,17 +305,15 @@ impl ToolExecutor<ExtensionToolCall> for WebRunExtensionTool {
         })
     }
 
-    async fn handle(
-        &self,
-        _call: ExtensionToolCall,
-    ) -> Result<Box<dyn ToolOutput>, codex_tools::FunctionCallError> {
-        Ok(Box::new(codex_tools::JsonToolOutput::new(json!({}))))
+    fn handle(&self, _call: ExtensionToolCall) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(async {
+            Ok(Box::new(codex_tools::JsonToolOutput::new(json!({}))) as Box<dyn ToolOutput>)
+        })
     }
 }
 
 struct DeferredExtensionTool;
 
-#[async_trait::async_trait]
 impl ToolExecutor<ExtensionToolCall> for DeferredExtensionTool {
     fn tool_name(&self) -> ToolName {
         ToolName::plain("extension_echo")
@@ -344,11 +341,8 @@ impl ToolExecutor<ExtensionToolCall> for DeferredExtensionTool {
         ToolExposure::Deferred
     }
 
-    async fn handle(
-        &self,
-        _call: ExtensionToolCall,
-    ) -> Result<Box<dyn ToolOutput>, codex_tools::FunctionCallError> {
-        panic!("spec planning should not execute extension tools")
+    fn handle(&self, _call: ExtensionToolCall) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(async { panic!("spec planning should not execute extension tools") })
     }
 }
 
diff --git a/codex-rs/core/src/tools/tool_dispatch_trace_tests.rs b/codex-rs/core/src/tools/tool_dispatch_trace_tests.rs
index 69dc8ab5803..b09996872ea 100644
--- a/codex-rs/core/src/tools/tool_dispatch_trace_tests.rs
+++ b/codex-rs/core/src/tools/tool_dispatch_trace_tests.rs
@@ -30,7 +30,6 @@ struct TestHandler {
     tool_name: codex_tools::ToolName,
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolInvocation> for TestHandler {
     fn tool_name(&self) -> codex_tools::ToolName {
         self.tool_name.clone()
@@ -47,14 +46,13 @@ impl ToolExecutor<ToolInvocation> for TestHandler {
         })
     }
 
-    async fn handle(
-        &self,
-        _invocation: ToolInvocation,
-    ) -> Result<Box<dyn crate::tools::context::ToolOutput>, FunctionCallError> {
-        Ok(Box::new(FunctionToolOutput::from_text(
-            "ok".to_string(),
-            Some(true),
-        )))
+    fn handle(&self, _invocation: ToolInvocation) -> codex_tools::ToolExecutorFuture<'_> {
+        Box::pin(async {
+            Ok(
+                Box::new(FunctionToolOutput::from_text("ok".to_string(), Some(true)))
+                    as Box<dyn crate::tools::context::ToolOutput>,
+            )
+        })
     }
 }
 
diff --git a/codex-rs/ext/extension-api/src/lib.rs b/codex-rs/ext/extension-api/src/lib.rs
index dc3495a71c0..52f15c894c3 100644
--- a/codex-rs/ext/extension-api/src/lib.rs
+++ b/codex-rs/ext/extension-api/src/lib.rs
@@ -20,6 +20,7 @@ pub use codex_tools::NoopTurnItemEmitter;
 pub use codex_tools::ResponsesApiTool;
 pub use codex_tools::ToolCall;
 pub use codex_tools::ToolExecutor;
+pub use codex_tools::ToolExecutorFuture;
 pub use codex_tools::ToolName;
 pub use codex_tools::ToolOutput;
 pub use codex_tools::ToolPayload;
diff --git a/codex-rs/ext/goal/Cargo.toml b/codex-rs/ext/goal/Cargo.toml
index 1e21f5ac884..4d75ba2f26a 100644
--- a/codex-rs/ext/goal/Cargo.toml
+++ b/codex-rs/ext/goal/Cargo.toml
@@ -14,7 +14,6 @@ doctest = false
 workspace = true
 
 [dependencies]
-async-trait = { workspace = true }
 codex-analytics = { workspace = true }
 codex-core = { workspace = true }
 codex-extension-api = { workspace = true }
diff --git a/codex-rs/ext/goal/src/tool.rs b/codex-rs/ext/goal/src/tool.rs
index c45ed81b0ad..d280f6e04b6 100644
--- a/codex-rs/ext/goal/src/tool.rs
+++ b/codex-rs/ext/goal/src/tool.rs
@@ -1,6 +1,5 @@
 use std::sync::Arc;
 
-use async_trait::async_trait;
 use codex_extension_api::FunctionCallError;
 use codex_extension_api::JsonToolOutput;
 use codex_extension_api::ToolCall;
@@ -132,7 +131,6 @@ impl GoalToolExecutor {
     }
 }
 
-#[async_trait]
 impl ToolExecutor<ToolCall> for GoalToolExecutor {
     fn tool_name(&self) -> ToolName {
         ToolName::plain(match self.kind {
@@ -150,12 +148,14 @@ impl ToolExecutor<ToolCall> for GoalToolExecutor {
         }
     }
 
-    async fn handle(&self, invocation: ToolCall) -> Result<Box<dyn ToolOutput>, FunctionCallError> {
-        match self.kind {
-            GoalToolKind::Get => self.handle_get(invocation).await,
-            GoalToolKind::Create => self.handle_create(invocation).await,
-            GoalToolKind::Update => self.handle_update(invocation).await,
-        }
+    fn handle(&self, invocation: ToolCall) -> codex_extension_api::ToolExecutorFuture<'_> {
+        Box::pin(async move {
+            match self.kind {
+                GoalToolKind::Get => self.handle_get(invocation).await,
+                GoalToolKind::Create => self.handle_create(invocation).await,
+                GoalToolKind::Update => self.handle_update(invocation).await,
+            }
+        })
     }
 }
 
diff --git a/codex-rs/ext/image-generation/Cargo.toml b/codex-rs/ext/image-generation/Cargo.toml
index cb5ddda0a81..dfa85ee82e1 100644
--- a/codex-rs/ext/image-generation/Cargo.toml
+++ b/codex-rs/ext/image-generation/Cargo.toml
@@ -13,7 +13,6 @@ doctest = false
 workspace = true
 
 [dependencies]
-async-trait = { workspace = true }
 codex-api = { workspace = true }
 codex-core = { workspace = true }
 codex-extension-api = { workspace = true }
diff --git a/codex-rs/ext/image-generation/src/tool.rs b/codex-rs/ext/image-generation/src/tool.rs
index 70880b4661f..07ed8f4bf6f 100644
--- a/codex-rs/ext/image-generation/src/tool.rs
+++ b/codex-rs/ext/image-generation/src/tool.rs
@@ -78,7 +78,6 @@ struct ImagegenArgs {
     num_last_images_to_include: Option<usize>,
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolCall> for ImageGenerationTool {
     /// Keeps the tool in the existing image-generation Responses namespace.
     fn tool_name(&self) -> ToolName {
@@ -96,8 +95,8 @@ impl ToolExecutor<ToolCall> for ImageGenerationTool {
     }
 
     /// Executes the selected image operation and returns the completed image result.
-    async fn handle(&self, call: ToolCall) -> Result<Box<dyn ToolOutput>, FunctionCallError> {
-        self.handle_call(call).await
+    fn handle(&self, call: ToolCall) -> codex_extension_api::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(call))
     }
 }
 
diff --git a/codex-rs/ext/memories/Cargo.toml b/codex-rs/ext/memories/Cargo.toml
index 68eeaf8ec1b..e283140b15e 100644
--- a/codex-rs/ext/memories/Cargo.toml
+++ b/codex-rs/ext/memories/Cargo.toml
@@ -13,7 +13,6 @@ doctest = false
 workspace = true
 
 [dependencies]
-async-trait = { workspace = true }
 codex-core = { workspace = true }
 codex-extension-api = { workspace = true }
 codex-features = { workspace = true }
diff --git a/codex-rs/ext/memories/src/tools/ad_hoc_note.rs b/codex-rs/ext/memories/src/tools/ad_hoc_note.rs
index 3495d57d328..0ce9cade676 100644
--- a/codex-rs/ext/memories/src/tools/ad_hoc_note.rs
+++ b/codex-rs/ext/memories/src/tools/ad_hoc_note.rs
@@ -41,7 +41,6 @@ pub(super) struct AddAdHocNoteTool<B> {
     pub(super) metrics_client: Option<MetricsClient>,
 }
 
-#[async_trait::async_trait]
 impl<B> ToolExecutor<ToolCall> for AddAdHocNoteTool<B>
 where
     B: MemoriesBackend,
@@ -57,12 +56,8 @@ where
         )
     }
 
-    async fn handle(
-        &self,
-        call: ToolCall,
-    ) -> Result<Box<dyn codex_extension_api::ToolOutput>, codex_extension_api::FunctionCallError>
-    {
-        self.handle_call(call).await
+    fn handle(&self, call: ToolCall) -> codex_extension_api::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(call))
     }
 }
 
diff --git a/codex-rs/ext/memories/src/tools/list.rs b/codex-rs/ext/memories/src/tools/list.rs
index d3b23b1ca2e..b7b9ad05862 100644
--- a/codex-rs/ext/memories/src/tools/list.rs
+++ b/codex-rs/ext/memories/src/tools/list.rs
@@ -39,7 +39,6 @@ pub(super) struct ListTool<B> {
     pub(super) metrics_client: Option<MetricsClient>,
 }
 
-#[async_trait::async_trait]
 impl<B> ToolExecutor<ToolCall> for ListTool<B>
 where
     B: MemoriesBackend,
@@ -55,12 +54,8 @@ where
         )
     }
 
-    async fn handle(
-        &self,
-        call: ToolCall,
-    ) -> Result<Box<dyn codex_extension_api::ToolOutput>, codex_extension_api::FunctionCallError>
-    {
-        self.handle_call(call).await
+    fn handle(&self, call: ToolCall) -> codex_extension_api::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(call))
     }
 }
 
diff --git a/codex-rs/ext/memories/src/tools/read.rs b/codex-rs/ext/memories/src/tools/read.rs
index e408a17cad7..6625cdaf8bd 100644
--- a/codex-rs/ext/memories/src/tools/read.rs
+++ b/codex-rs/ext/memories/src/tools/read.rs
@@ -38,7 +38,6 @@ pub(super) struct ReadTool<B> {
     pub(super) metrics_client: Option<MetricsClient>,
 }
 
-#[async_trait::async_trait]
 impl<B> ToolExecutor<ToolCall> for ReadTool<B>
 where
     B: MemoriesBackend,
@@ -54,12 +53,8 @@ where
         )
     }
 
-    async fn handle(
-        &self,
-        call: ToolCall,
-    ) -> Result<Box<dyn codex_extension_api::ToolOutput>, codex_extension_api::FunctionCallError>
-    {
-        self.handle_call(call).await
+    fn handle(&self, call: ToolCall) -> codex_extension_api::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(call))
     }
 }
 
diff --git a/codex-rs/ext/memories/src/tools/search.rs b/codex-rs/ext/memories/src/tools/search.rs
index cc8ba201a65..928c98b475d 100644
--- a/codex-rs/ext/memories/src/tools/search.rs
+++ b/codex-rs/ext/memories/src/tools/search.rs
@@ -47,7 +47,6 @@ pub(super) struct SearchTool<B> {
     pub(super) metrics_client: Option<MetricsClient>,
 }
 
-#[async_trait::async_trait]
 impl<B> ToolExecutor<ToolCall> for SearchTool<B>
 where
     B: MemoriesBackend,
@@ -63,12 +62,8 @@ where
         )
     }
 
-    async fn handle(
-        &self,
-        call: ToolCall,
-    ) -> Result<Box<dyn codex_extension_api::ToolOutput>, codex_extension_api::FunctionCallError>
-    {
-        self.handle_call(call).await
+    fn handle(&self, call: ToolCall) -> codex_extension_api::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(call))
     }
 }
 
diff --git a/codex-rs/ext/web-search/Cargo.toml b/codex-rs/ext/web-search/Cargo.toml
index 954ac3dac9e..d007d6146de 100644
--- a/codex-rs/ext/web-search/Cargo.toml
+++ b/codex-rs/ext/web-search/Cargo.toml
@@ -13,7 +13,6 @@ doctest = false
 workspace = true
 
 [dependencies]
-async-trait = { workspace = true }
 codex-api = { workspace = true }
 codex-core = { workspace = true }
 codex-extension-api = { workspace = true }
diff --git a/codex-rs/ext/web-search/src/tool.rs b/codex-rs/ext/web-search/src/tool.rs
index 1de65edf865..9b8dbf56d6f 100644
--- a/codex-rs/ext/web-search/src/tool.rs
+++ b/codex-rs/ext/web-search/src/tool.rs
@@ -39,7 +39,6 @@ pub(crate) struct WebSearchTool {
     pub(crate) settings: SearchSettings,
 }
 
-#[async_trait::async_trait]
 impl ToolExecutor<ToolCall> for WebSearchTool {
     fn tool_name(&self) -> ToolName {
         ToolName::namespaced(WEB_NAMESPACE, RUN_TOOL_NAME)
@@ -74,8 +73,8 @@ impl ToolExecutor<ToolCall> for WebSearchTool {
         true
     }
 
-    async fn handle(&self, call: ToolCall) -> Result<Box<dyn ToolOutput>, FunctionCallError> {
-        self.handle_call(call).await
+    fn handle(&self, call: ToolCall) -> codex_extension_api::ToolExecutorFuture<'_> {
+        Box::pin(self.handle_call(call))
     }
 }
 
diff --git a/codex-rs/tools/Cargo.toml b/codex-rs/tools/Cargo.toml
index 7cc0e348458..4b2a3257f39 100644
--- a/codex-rs/tools/Cargo.toml
+++ b/codex-rs/tools/Cargo.toml
@@ -8,7 +8,6 @@ version.workspace = true
 workspace = true
 
 [dependencies]
-async-trait = { workspace = true }
 codex-app-server-protocol = { workspace = true }
 codex-code-mode = { workspace = true }
 codex-features = { workspace = true }
diff --git a/codex-rs/tools/src/lib.rs b/codex-rs/tools/src/lib.rs
index 1cee3f7d2d5..848bab3e1c0 100644
--- a/codex-rs/tools/src/lib.rs
+++ b/codex-rs/tools/src/lib.rs
@@ -93,6 +93,7 @@ pub use tool_discovery::ToolSearchSourceInfo;
 pub use tool_discovery::collect_request_plugin_install_entries;
 pub use tool_discovery::filter_request_plugin_install_discoverable_tools_for_client;
 pub use tool_executor::ToolExecutor;
+pub use tool_executor::ToolExecutorFuture;
 pub use tool_executor::ToolExposure;
 pub use tool_output::JsonToolOutput;
 pub use tool_output::ToolOutput;
diff --git a/codex-rs/tools/src/tool_executor.rs b/codex-rs/tools/src/tool_executor.rs
index 541d2443e0c..708ed1c3b1f 100644
--- a/codex-rs/tools/src/tool_executor.rs
+++ b/codex-rs/tools/src/tool_executor.rs
@@ -3,6 +3,12 @@ use crate::ToolName;
 use crate::ToolOutput;
 use crate::ToolSearchInfo;
 use crate::ToolSpec;
+use std::future::Future;
+use std::pin::Pin;
+
+/// The boxed future returned by [`ToolExecutor::handle`].
+pub type ToolExecutorFuture<'a> =
+    Pin<Box<dyn Future<Output = Result<Box<dyn ToolOutput>, FunctionCallError>> + Send + 'a>>;
 
 /// Controls where a tool is exposed to the model.
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
@@ -40,7 +46,6 @@ impl ToolExposure {
 /// Implementations keep the model-visible spec tied to the executable runtime.
 /// Host crates can layer routing, hooks, telemetry, or other orchestration on
 /// top without reopening the spec/runtime split.
-#[async_trait::async_trait]
 pub trait ToolExecutor<Invocation>: Send + Sync {
     /// The concrete tool name handled by this runtime instance.
     fn tool_name(&self) -> ToolName;
@@ -60,8 +65,5 @@ pub trait ToolExecutor<Invocation>: Send + Sync {
         false
     }
 
-    async fn handle(
-        &self,
-        invocation: Invocation,
-    ) -> Result<Box<dyn ToolOutput>, FunctionCallError>;
+    fn handle(&self, invocation: Invocation) -> ToolExecutorFuture<'_>;
 }