Control network egress

The runtime HTTP client is always present, but what it can reach is first shaped by the manifest and then adjusted further at startup through runtime configuration. This guide shows how to start from the default policy and narrow it to the exact network surface a component needs.

Start from the default

With no network block, outbound requests are unrestricted by URL pattern. Loopback, private, and link-local addresses are still refused by default.

The manifest is the first place network policy is defined. Runtime configuration can also control the policy at startup, including when the manifest omits the network block entirely, so one compiled binary can still be tightened or relaxed per deployment.

Allow one API host

Add a network block with a single allow pattern when the component should reach one API host and nothing else.

network {
  policy {
    allow = [
      {
        protocol = "https"
        hostname = "api.example.com"
      }
    ]
  }
}

Requests to any other host are now refused.

Narrow the methods

Add methods to limit which HTTP methods the client may use. When methods is unset, methods are unrestricted.

network {
  policy {
    methods = ["GET", "POST"]

    allow = [
      {
        protocol = "https"
        hostname = "api.example.com"
      }
    ]
  }
}

Set a timeout

Add request_timeout_ms when the whole request should have a deadline. Use runtime() when the operator should be able to adjust the value at startup.

network {
  limits {
    request_timeout_ms = runtime("NETWORK_REQUEST_TIMEOUT_MS", 5000)
  }

  policy {
    allow = [
      {
        protocol = "https"
        hostname = "api.example.com"
      }
    ]
  }
}

Permit an address class for local development

Loopback is off by default because allowing it lets component code talk to services bound on the same machine, which is usually broader access than a production agent should have. Make it runtime configurable when local development needs it.

network {
  policy {
    addresses {
      allow_loopback = runtime("NETWORK_ALLOW_LOOPBACK", false)
    }

    allow = [
      {
        protocol = "http"
        hostname = "127.0.0.1"
        port     = "3000"
      }
    ]
  }
}

The default stays off, but an operator can enable it where it is explicitly wanted.

Make a request from a component

Send a request from a component using the corresponding runtime library.

import { fetch } from "agentc:http";

try {
  const response = await fetch("https://api.example.com/status");

  if (!response.ok) {
    throw new Error(`upstream returned ${response.status}`);
  }

  const body = await response.text();
  console.log(body);
} catch (error) {
  console.error(String(error));
}

If the request violates the egress policy, fetch rejects and the error message explains the refusal.

Where to go next

• network reference
• agentc:http