Preserve namespaces on custom tool calls

codex-rs/core/src/codex_delegate_tests.rs

@@ -80,6 +80,7 @@ async fn forward_events_cancelled_while_send_blocked_shuts_down_delegate() {
                     status: None,
                     call_id: "call-1".to_string(),
                     name: "tool".to_string(),
+                    namespace: None,
                     input: "{}".to_string(),
                     internal_chat_message_metadata_passthrough: None,
                 },

codex-rs/core/src/context_manager/history_tests.rs

@@ -513,6 +513,7 @@ fn for_prompt_strips_images_when_model_does_not_support_images() {
             status: None,
             call_id: "tool-1".to_string(),
             name: "js_repl".to_string(),
+            namespace: None,
             input: "view_image".to_string(),
             internal_chat_message_metadata_passthrough: None,
         },
@@ -582,6 +583,7 @@ fn for_prompt_strips_images_when_model_does_not_support_images() {
             status: None,
             call_id: "tool-1".to_string(),
             name: "js_repl".to_string(),
+            namespace: None,
             input: "view_image".to_string(),
             internal_chat_message_metadata_passthrough: None,
         },
@@ -1090,6 +1092,7 @@ fn remove_first_item_handles_custom_tool_pair() {
             status: None,
             call_id: "tool-1".to_string(),
             name: "my_tool".to_string(),
+            namespace: None,
             input: "{}".to_string(),
             internal_chat_message_metadata_passthrough: None,
         },
@@ -1378,6 +1381,7 @@ fn normalize_adds_missing_output_for_custom_tool_call() {
         status: None,
         call_id: "tool-x".to_string(),
         name: "custom".to_string(),
+        namespace: None,
         input: "{}".to_string(),
         internal_chat_message_metadata_passthrough: None,
     }];
@@ -1393,6 +1397,7 @@ fn normalize_adds_missing_output_for_custom_tool_call() {
                 status: None,
                 call_id: "tool-x".to_string(),
                 name: "custom".to_string(),
+                namespace: None,
                 input: "{}".to_string(),
                 internal_chat_message_metadata_passthrough: None,
             },
@@ -1512,6 +1517,7 @@ fn normalize_mixed_inserts_and_removals() {
             status: None,
             call_id: "t1".to_string(),
             name: "tool".to_string(),
+            namespace: None,
             input: "{}".to_string(),
             internal_chat_message_metadata_passthrough: None,
         },
@@ -1556,6 +1562,7 @@ fn normalize_mixed_inserts_and_removals() {
                 status: None,
                 call_id: "t1".to_string(),
                 name: "tool".to_string(),
+                namespace: None,
                 input: "{}".to_string(),
                 internal_chat_message_metadata_passthrough: None,
             },
@@ -1668,6 +1675,7 @@ fn normalize_adds_missing_output_for_custom_tool_call_panics_in_debug() {
         status: None,
         call_id: "tool-x".to_string(),
         name: "custom".to_string(),
+        namespace: None,
         input: "{}".to_string(),
         internal_chat_message_metadata_passthrough: None,
     }];
@@ -1810,6 +1818,7 @@ fn normalize_mixed_inserts_and_removals_panics_in_debug() {
             status: None,
             call_id: "t1".to_string(),
             name: "tool".to_string(),
+            namespace: None,
             input: "{}".to_string(),
             internal_chat_message_metadata_passthrough: None,
         },

codex-rs/core/src/session/tests.rs

@@ -10482,6 +10482,7 @@ async fn fatal_tool_error_stops_turn_and_reports_error() {
         status: None,
         call_id: "call-1".to_string(),
         name: "shell_command".to_string(),
+        namespace: None,
         input: "{}".to_string(),
         internal_chat_message_metadata_passthrough: None,
     };

codex-rs/core/src/session/turn.rs

@@ -2080,8 +2080,14 @@ async fn try_run_sampling_request(
                 }
             }
             ResponseEvent::OutputItemAdded(item) => {
-                if let ResponseItem::CustomToolCall { call_id, name, .. } = &item {
-                    let tool_name = ToolName::plain(name.as_str());
+                if let ResponseItem::CustomToolCall {
+                    call_id,
+                    name,
+                    namespace,
+                    ..
+                } = &item
+                {
+                    let tool_name = ToolName::new(namespace.clone(), name.as_str());
                     active_tool_argument_diff_consumer = tool_runtime
                         .create_diff_consumer(&tool_name)
                         .map(|consumer| (call_id.clone(), consumer));

codex-rs/core/src/stream_events_utils_tests.rs

@@ -116,6 +116,7 @@ fn external_context_pollution_items_exclude_local_tool_calls() {
             status: None,
             call_id: "custom-1".to_string(),
             name: "apply_patch".to_string(),
+            namespace: None,
             input: "*** Begin Patch\n*** End Patch\n".to_string(),
             internal_chat_message_metadata_passthrough: None,
         },

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

@@ -25,7 +25,7 @@ use tracing::instrument;
 
 pub use crate::tools::context::ToolCallSource;
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
 pub struct ToolCall {
     pub tool_name: ToolName,
     pub call_id: String,
@@ -147,11 +147,12 @@ impl ToolRouter {
             ResponseItem::ToolSearchCall { .. } => Ok(None),
             ResponseItem::CustomToolCall {
                 name,
+                namespace,
                 input,
                 call_id,
                 ..
             } => Ok(Some(ToolCall {
-                tool_name: ToolName::plain(name),
+                tool_name: ToolName::new(namespace, name),
                 call_id,
                 payload: ToolPayload::Custom { input },
             })),

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

@@ -179,6 +179,35 @@ async fn build_tool_call_uses_namespace_for_registry_name() -> anyhow::Result<()
     Ok(())
 }
 
+#[tokio::test]
+async fn build_custom_tool_call_uses_namespace_for_registry_name() -> anyhow::Result<()> {
+    let tool_name = "exec".to_string();
+
+    let call = ToolRouter::build_tool_call(ResponseItem::CustomToolCall {
+        id: None,
+        status: None,
+        call_id: "call-namespace".to_string(),
+        name: tool_name.clone(),
+        namespace: Some("mcp__python".to_string()),
+        input: "print('hello')".to_string(),
+        internal_chat_message_metadata_passthrough: None,
+    })?
+    .expect("custom_tool_call should produce a tool call");
+
+    assert_eq!(
+        call,
+        ToolCall {
+            tool_name: ToolName::namespaced("mcp__python", tool_name),
+            call_id: "call-namespace".to_string(),
+            payload: ToolPayload::Custom {
+                input: "print('hello')".to_string(),
+            },
+        }
+    );
+
+    Ok(())
+}
+
 #[tokio::test]
 async fn mcp_parallel_support_uses_handler_data() -> anyhow::Result<()> {
     let (_, turn) = make_session_and_context().await;

codex-rs/core/src/turn_timing_tests.rs

@@ -121,6 +121,7 @@ fn response_item_records_turn_ttft_for_first_output_signals() {
             status: None,
             call_id: "call-2".to_string(),
             name: "custom".to_string(),
+            namespace: None,
             input: "echo hi".to_string(),
             internal_chat_message_metadata_passthrough: None,
         }