agent-computer: COMPUTER_BIND chooses the address a managed computer listens on

.env.example

@@ -343,6 +343,13 @@ COMPUTER_TOKEN=
 # credentialed proxy here is an operator's decision.
 # COMPUTER_SHELL_ENV=JAVA_HOME,GOPATH
 
+# The address the computer listens on. Unset, a managed computer listens on every interface, which
+# a container needs. A computer run straight on a laptop (`bun run dev` in agent-computer) is then
+# reachable from the local network too; its API needs the computer token, but nothing else needs to
+# reach it, so set 127.0.0.1 there. A computer driving a native Chrome (OpenBot Desktop's) always
+# listens on loopback, whatever this says.
+# COMPUTER_BIND=127.0.0.1
+
 # ---------------------------------------------------------------------------
 # The computer's profile and where its traffic leaves from
 # ---------------------------------------------------------------------------

CHANGELOG.md

@@ -84,6 +84,14 @@ The built-in safety rules hand paying, purchasing or moving money to you, but a
 (such as `SHOPIFY_CREATE_REFUND`) passed straight through: "refund" was not one of the words the
 rule looked for. It is now, so issuing a refund is handed to you like any other movement of money.
 
+### A computer run on a laptop can stay off the local network
+
+A managed computer listens on every network interface, which a container needs. Run straight on a
+laptop with `bun run dev`, that left its token-protected API reachable from the local network.
+`COMPUTER_BIND` now chooses the address it listens on: set `COMPUTER_BIND=127.0.0.1` to keep it to
+the machine itself. Unset, nothing changes, and a computer driving a native Chrome (OpenBot
+Desktop's) still always listens on loopback.
+
 ### A computer closes browsers nobody is using when its memory runs high
 
 A computer runs one browser for each Bot that is browsing, and the only limits were a count and half

agent-computer/src/browser-runtime.ts

@@ -5,7 +5,7 @@ export type BrowserRuntime = {
   channel: "chromium" | "chrome";
   mode: BrowserMode;
   useVirtualDisplay: boolean;
-  hostname?: "127.0.0.1";
+  hostname?: string;
   allowExec: boolean;
 };
 
@@ -21,6 +21,9 @@ export function browserRuntimeFromEnv(
     );
   }
   const local = backend === "local-chrome";
+  // Where the HTTP process listens. Native Chrome always listens on loopback. A managed computer listens on every interface unless COMPUTER_BIND names an address,
+  // so a computer that runs on a person's own machine (not in a container) can be kept off the network: COMPUTER_BIND=127.0.0.1.
+  const bind = env.COMPUTER_BIND?.trim();
   /*
    * Headed wherever a hosted computer runs, which is Linux: a container, a Kubernetes pod, the
    * desktop app's Podman machine. Headless Chromium is the browser bot checks are best at spotting
@@ -45,7 +48,7 @@ export function browserRuntimeFromEnv(
     channel: local ? "chrome" : "chromium",
     mode,
     useVirtualDisplay: platform === "linux" && mode === "headed",
-    ...(local ? { hostname: "127.0.0.1" as const } : {}),
+    ...(local ? { hostname: "127.0.0.1" } : bind ? { hostname: bind } : {}),
     allowExec: !local,
   };
 }

agent-computer/tests/browser-runtime.test.ts

@@ -13,6 +13,16 @@ describe("the configured browser runtime", () => {
     });
   });
 
+  test("a managed computer listens on every interface unless COMPUTER_BIND names one", () => {
+    expect(browserRuntimeFromEnv({}, "linux").hostname).toBeUndefined();
+    expect(
+      browserRuntimeFromEnv({ COMPUTER_BIND: " 127.0.0.1 " }, "win32").hostname,
+    ).toBe("127.0.0.1");
+    expect(
+      browserRuntimeFromEnv({ COMPUTER_BIND: "127.0.0.1" }, "win32").allowExec,
+    ).toBe(true);
+  });
+
   test.each(["darwin", "win32"])(
     "managed %s, a developer's own machine, stays headless",
     (platform) => {