MCP Server Access

The MCP Gateway lets sandboxes interact with Model Context Protocol servers exposed at your enterprise — without giving the sandbox direct access to the underlying credentials.

A sandbox created with chalk_identity=True authenticates to the MCP Gateway with its workload identity, with no other credential. A sandbox created without it must send a Chalk access token in the Authorization header and the environment ID in the X-Chalk-Env-Id header.

The gateway validates the identity, then proxies the request to the upstream MCP server using credentials managed by your organization. The sandbox never sees the real credential.

┌─────────────┐        WIF token         ┌─────────────┐     real credential     ┌─────────────┐
│   Sandbox   │ ──────────────────────▸  │ MCP Gateway │ ──────────────────────▸ │  MCP Server │
└─────────────┘                          └─────────────┘                         └─────────────┘

This is particularly useful for agent workloads. A code-generation agent may need to call tool-use APIs, search indexes, or retrieval services. With the gateway:

The agent can leak its own temporary token without compromising the real upstream credential.
You retain centralized control over which MCP servers are reachable and by which workloads.
Audit logs capture every proxied call, tied to the originating workload identity.