Normalize /mcp tool grouping for hyphenated server names (#15946)

Fix display for servers with special characters.

codex-rs/core/src/mcp/mod.rs

@@ -33,6 +33,32 @@ const MCP_TOOL_NAME_DELIMITER: &str = "__";
 pub(crate) const CODEX_APPS_MCP_SERVER_NAME: &str = "codex_apps";
 const CODEX_CONNECTORS_TOKEN_ENV_VAR: &str = "CODEX_CONNECTORS_TOKEN";
 
+/// The Responses API requires tool names to match `^[a-zA-Z0-9_-]+$`.
+/// MCP server/tool names are user-controlled, so sanitize the fully-qualified
+/// name we expose to the model by replacing any disallowed character with `_`.
+pub(crate) fn sanitize_responses_api_tool_name(name: &str) -> String {
+    let mut sanitized = String::with_capacity(name.len());
+    for c in name.chars() {
+        if c.is_ascii_alphanumeric() || c == '_' {
+            sanitized.push(c);
+        } else {
+            sanitized.push('_');
+        }
+    }
+
+    if sanitized.is_empty() {
+        "_".to_string()
+    } else {
+        sanitized
+    }
+}
+
+pub fn qualified_mcp_tool_name_prefix(server_name: &str) -> String {
+    sanitize_responses_api_tool_name(&format!(
+        "{MCP_TOOL_NAME_PREFIX}{MCP_TOOL_NAME_DELIMITER}{server_name}{MCP_TOOL_NAME_DELIMITER}"
+    ))
+}
+
 #[derive(Debug, Clone, Default, PartialEq, Eq)]
 pub struct ToolPluginProvenance {
     plugin_display_names_by_connector_id: HashMap<String, Vec<String>>,

codex-rs/core/src/mcp/mod_tests.rs

@@ -52,6 +52,14 @@ fn split_qualified_tool_name_returns_server_and_tool() {
     );
 }
 
+#[test]
+fn qualified_mcp_tool_name_prefix_sanitizes_server_names_without_lowercasing() {
+    assert_eq!(
+        qualified_mcp_tool_name_prefix("Some-Server"),
+        "mcp__Some_Server__".to_string()
+    );
+}
+
 #[test]
 fn split_qualified_tool_name_rejects_invalid_names() {
     assert_eq!(split_qualified_tool_name("other__alpha__do_thing"), None);

codex-rs/core/src/mcp_connection_manager.rs

@@ -22,6 +22,7 @@ use std::time::Instant;
 use crate::mcp::CODEX_APPS_MCP_SERVER_NAME;
 use crate::mcp::ToolPluginProvenance;
 use crate::mcp::auth::McpAuthStatusEntry;
+use crate::mcp::sanitize_responses_api_tool_name;
 use anyhow::Context;
 use anyhow::Result;
 use anyhow::anyhow;
@@ -104,26 +105,6 @@ const MCP_TOOLS_LIST_DURATION_METRIC: &str = "codex.mcp.tools.list.duration_ms";
 const MCP_TOOLS_FETCH_UNCACHED_DURATION_METRIC: &str = "codex.mcp.tools.fetch_uncached.duration_ms";
 const MCP_TOOLS_CACHE_WRITE_DURATION_METRIC: &str = "codex.mcp.tools.cache_write.duration_ms";
 
-/// The Responses API requires tool names to match `^[a-zA-Z0-9_-]+$`.
-/// MCP server/tool names are user-controlled, so sanitize the fully-qualified
-/// name we expose to the model by replacing any disallowed character with `_`.
-fn sanitize_responses_api_tool_name(name: &str) -> String {
-    let mut sanitized = String::with_capacity(name.len());
-    for c in name.chars() {
-        if c.is_ascii_alphanumeric() || c == '_' {
-            sanitized.push(c);
-        } else {
-            sanitized.push('_');
-        }
-    }
-
-    if sanitized.is_empty() {
-        "_".to_string()
-    } else {
-        sanitized
-    }
-}
-
 fn sha1_hex(s: &str) -> String {
     let mut hasher = Sha1::new();
     hasher.update(s.as_bytes());