diff --git a/codex-rs/codex-mcp/src/connection_manager.rs b/codex-rs/codex-mcp/src/connection_manager.rs
index 858fc884da..e480251ea8 100644
--- a/codex-rs/codex-mcp/src/connection_manager.rs
+++ b/codex-rs/codex-mcp/src/connection_manager.rs
@@ -12,6 +12,7 @@ use std::sync::Arc;
 use std::sync::Mutex;
 use std::sync::PoisonError;
 use std::sync::RwLock;
+use std::sync::Weak;
 use std::sync::atomic::Ordering;
 use std::time::Duration;
 use std::time::Instant;
@@ -116,6 +117,7 @@ pub struct McpConnectionManager {
 }
 
 struct McpConnections {
+    resource_cache_identity: Arc<()>,
     clients: HashMap<String, AsyncManagedClient>,
     server_metadata: HashMap<String, McpServerMetadata>,
     required_servers: Vec<String>,
@@ -297,6 +299,7 @@ impl McpConnectionManager {
     ) -> Self {
         Self {
             connections: RwLock::new(Arc::new(McpConnections {
+                resource_cache_identity: Arc::new(()),
                 clients: HashMap::new(),
                 server_metadata: HashMap::new(),
                 required_servers: Vec::new(),
@@ -321,6 +324,10 @@ impl McpConnectionManager {
         self.connections().clients.contains_key(server_name)
     }
 
+    pub(crate) fn resource_cache_key(&self) -> Weak<()> {
+        Arc::downgrade(&self.connections().resource_cache_identity)
+    }
+
     /// Cancels MCP servers that are still starting without shutting down ready clients.
     pub fn cancel_startup(&self) {
         self.startup_cancellation_token
@@ -975,6 +982,7 @@ async fn start_connections(
         });
     }
     let connections = McpConnections {
+        resource_cache_identity: Arc::new(()),
         clients,
         server_metadata,
         required_servers,
diff --git a/codex-rs/codex-mcp/src/resource_client.rs b/codex-rs/codex-mcp/src/resource_client.rs
index 4406b81a53..c4ef2b1d84 100644
--- a/codex-rs/codex-mcp/src/resource_client.rs
+++ b/codex-rs/codex-mcp/src/resource_client.rs
@@ -36,9 +36,9 @@ pub struct McpResourceClient {
     manager: Arc<ArcSwap<McpConnectionManager>>,
 }
 
-/// Opaque identity for the manager currently used by an MCP resource client.
+/// Opaque identity for the connection snapshot currently used by an MCP resource client.
 #[derive(Clone)]
-pub struct McpResourceClientCacheKey(Weak<McpConnectionManager>);
+pub struct McpResourceClientCacheKey(Weak<()>);
 
 impl PartialEq for McpResourceClientCacheKey {
     fn eq(&self, other: &Self) -> bool {
@@ -62,9 +62,9 @@ impl McpResourceClient {
         Self { manager }
     }
 
-    /// Returns an identity that changes whenever the published manager changes.
+    /// Returns an identity that changes whenever the manager's connections change.
     pub fn cache_key(&self) -> McpResourceClientCacheKey {
-        McpResourceClientCacheKey(Arc::downgrade(&self.manager.load_full()))
+        McpResourceClientCacheKey(self.manager.load_full().resource_cache_key())
     }
 
     /// Returns whether the current manager contains the named server.