Codex MCP and Dome

1. 01

   Turn on interactive access

   The allow-list takes exact emails or identity provider subjects. Turning access on creates the managed agent Codex sessions run as.

   $ dome gateways interactive enable eng-gateway \
     --email priya@example.com \
     --email tom@example.com

2. 02

   Permit what it may call

   Attach the rule below to that agent with --agent. dome gateways get prints the name.

   $ dome rules apply interactive-access.cedar \
     --agent gateway-interactive-<gateway-id> \
     --name interactive-access

3. 03

   Add the Gateway to Codex

   This writes the server to ~/.codex/config.toml with no token. The login opens a browser to sign in.

   $ codex mcp add dome \
     --url https://<gateway-host>/gateways/<gateway-id>/mcp
   $ codex mcp login dome

Commands and rules tested against a Dome workspace on October 1, 2026. For anything about Codex itself, see OpenAI's documentation.

permit (
  principal is Dome::Agent,
  action == Dome::Action::"mcp:discover",
  resource
);
 
permit (
  principal is Dome::Agent,
  action == Dome::Action::"mcp:call",
  resource is Dome::MCPTool
) when { resource.connection_name == "github" };
 
forbid (principal, action == Dome::Action::"mcp:call", resource is Dome::MCPTool)
when {
  resource.connection_name == "github" &&
  resource.tool_name == "merge_pull_request"
}
unless {
  principal has act_as &&
  principal.act_as.email == "priya@example.com"
};