From 9c3da20b3f6dadf60646d6fb16f5e357c234760d Mon Sep 17 00:00:00 2001
From: jif <jif@openai.com>
Date: Fri, 21 Aug 2026 13:15:46 +0000
Subject: [PATCH] Track remote MCP header environment variables (#39930)

## Why

Remote HTTP MCP connections can source header values from the host environment,
so those variables must remain part of the connection identity even when the MCP
server runs in an executor environment.

## What changed

- Track `env_http_headers` variables for remote HTTP MCP connections.
- Continue tracking `bearer_token_env_var` only for local environments, where the
  host resolves the token.

## Testing

Add coverage that verifies remote connections track host header variables without
tracking executor bearer-token variables, while local connections track both.

GitOrigin-RevId: 8fe175c54a101721a27b76495dcd298f0c2bc6a3
---
 codex-rs/codex-mcp/src/server.rs       |  8 ++++---
 codex-rs/codex-mcp/src/server_tests.rs | 32 ++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 3 deletions(-)
 create mode 100644 codex-rs/codex-mcp/src/server_tests.rs

diff --git a/codex-rs/codex-mcp/src/server.rs b/codex-rs/codex-mcp/src/server.rs
index f0e739a904..002e1d5e99 100644
--- a/codex-rs/codex-mcp/src/server.rs
+++ b/codex-rs/codex-mcp/src/server.rs
@@ -329,15 +329,13 @@ fn referenced_environment_variables(config: &McpServerConfig) -> Vec<(String, Op
             .filter(|env_var| !env_var.is_remote_source())
             .map(|env_var| env_var.name().to_string())
             .collect::<Vec<_>>(),
-        McpServerTransportConfig::StreamableHttp { .. } if !config.is_local_environment() => {
-            Vec::new()
-        }
         McpServerTransportConfig::StreamableHttp {
             bearer_token_env_var,
             env_http_headers,
             ..
         } => bearer_token_env_var
             .iter()
+            .filter(|_| config.is_local_environment())
             .chain(env_http_headers.iter().flat_map(|headers| headers.values()))
             .cloned()
             .collect(),
@@ -421,3 +419,7 @@ impl From<&EffectiveMcpServer> for McpServerMetadata {
         }
     }
 }
+
+#[cfg(test)]
+#[path = "server_tests.rs"]
+mod tests;
diff --git a/codex-rs/codex-mcp/src/server_tests.rs b/codex-rs/codex-mcp/src/server_tests.rs
new file mode 100644
index 0000000000..87992a8800
--- /dev/null
+++ b/codex-rs/codex-mcp/src/server_tests.rs
@@ -0,0 +1,32 @@
+use super::referenced_environment_variables;
+use codex_config::DEFAULT_MCP_SERVER_ENVIRONMENT_ID;
+use codex_config::McpServerConfig;
+use pretty_assertions::assert_eq;
+
+#[test]
+fn remote_http_connections_track_host_headers_but_not_executor_bearer_tokens() {
+    let mut config: McpServerConfig = serde_json::from_value(serde_json::json!({
+        "url": "https://example.com/mcp",
+        "environment_id": "executor-1",
+        "bearer_token_env_var": "NODE_REPL_AUTH_TOKEN",
+        "env_http_headers": {"X-Api-Key": "PATH"},
+    }))
+    .expect("remote MCP configuration should deserialize");
+
+    assert_eq!(
+        referenced_environment_variables(&config),
+        vec![("PATH".to_string(), std::env::var_os("PATH"))],
+    );
+
+    config.environment_id = DEFAULT_MCP_SERVER_ENVIRONMENT_ID.to_string();
+    assert_eq!(
+        referenced_environment_variables(&config),
+        vec![
+            (
+                "NODE_REPL_AUTH_TOKEN".to_string(),
+                std::env::var_os("NODE_REPL_AUTH_TOKEN"),
+            ),
+            ("PATH".to_string(), std::env::var_os("PATH")),
+        ],
+    );
+}