From 64815da52cc7610886fbdb2545caba0ec080fde2 Mon Sep 17 00:00:00 2001
From: Sayan Sisodiya <sayan@openai.com>
Date: Sat, 11 Apr 2026 18:59:20 -0700
Subject: [PATCH] Fix MCP resolution for split flat names

---
 .../codex-mcp/src/mcp_connection_manager.rs   | 19 +++++++++++--------
 .../src/mcp_connection_manager_tests.rs       | 13 +++++++++++++
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/codex-rs/codex-mcp/src/mcp_connection_manager.rs b/codex-rs/codex-mcp/src/mcp_connection_manager.rs
index 97e8e30ad8..54838b6ea4 100644
--- a/codex-rs/codex-mcp/src/mcp_connection_manager.rs
+++ b/codex-rs/codex-mcp/src/mcp_connection_manager.rs
@@ -1200,15 +1200,18 @@ impl McpConnectionManager {
 
     pub async fn resolve_tool_info(&self, tool_name: &ToolName) -> Option<ToolInfo> {
         let all_tools = self.list_all_tools().await;
-        if tool_name.namespace.is_some() {
-            let tools_by_name = all_tools
-                .into_values()
-                .map(|tool| (tool.callable_tool_name(), tool))
-                .collect::<HashMap<_, _>>();
-            tools_by_name.get(tool_name).cloned()
-        } else {
-            all_tools.get(&tool_name.name).cloned()
+        let tools_by_name = all_tools
+            .into_values()
+            .map(|tool| (tool.callable_tool_name(), tool))
+            .collect::<HashMap<_, _>>();
+
+        if let Some(tool) = tools_by_name.get(tool_name) {
+            return Some(tool.clone());
         }
+
+        tools_by_name
+            .into_iter()
+            .find_map(|(name, tool)| (name.display() == tool_name.name).then_some(tool))
     }
 
     pub async fn notify_sandbox_state_change(&self, sandbox_state: &SandboxState) -> Result<()> {
diff --git a/codex-rs/codex-mcp/src/mcp_connection_manager_tests.rs b/codex-rs/codex-mcp/src/mcp_connection_manager_tests.rs
index 427fc9308d..f093918211 100644
--- a/codex-rs/codex-mcp/src/mcp_connection_manager_tests.rs
+++ b/codex-rs/codex-mcp/src/mcp_connection_manager_tests.rs
@@ -674,6 +674,10 @@ async fn resolve_tool_info_accepts_plain_and_namespaced_tool_names() {
         .resolve_tool_info(&ToolName::namespaced("mcp__rmcp__", "echo"))
         .await
         .expect("split MCP tool namespace and name should resolve");
+    let split_with_flat_name = manager
+        .resolve_tool_info(&ToolName::namespaced("mcp__rmcp__", "mcp__rmcp__echo"))
+        .await
+        .expect("split namespace with flat qualified MCP tool name should resolve");
 
     let expected = ("rmcp", "mcp__rmcp__", "echo", "echo");
     assert_eq!(
@@ -694,6 +698,15 @@ async fn resolve_tool_info_accepts_plain_and_namespaced_tool_names() {
         ),
         expected
     );
+    assert_eq!(
+        (
+            split_with_flat_name.server_name.as_str(),
+            split_with_flat_name.callable_namespace.as_str(),
+            split_with_flat_name.callable_name.as_str(),
+            split_with_flat_name.tool.name.as_ref(),
+        ),
+        expected
+    );
 }
 
 #[tokio::test]