diff --git a/packages/adapter-utils/src/server-utils.ts b/packages/adapter-utils/src/server-utils.ts
index 9de5b7cc..1c8b76bd 100644
--- a/packages/adapter-utils/src/server-utils.ts
+++ b/packages/adapter-utils/src/server-utils.ts
@@ -91,11 +91,21 @@ export function redactEnvForLogs(env: Record<string, string>): Record<string, st
 }
 
 export function buildPaperclipEnv(agent: { id: string; companyId: string }): Record<string, string> {
+  const resolveHostForUrl = (rawHost: string): string => {
+    const host = rawHost.trim();
+    if (!host || host === "0.0.0.0" || host === "::") return "localhost";
+    if (host.includes(":") && !host.startsWith("[") && !host.endsWith("]")) return `[${host}]`;
+    return host;
+  };
   const vars: Record<string, string> = {
     PAPERCLIP_AGENT_ID: agent.id,
     PAPERCLIP_COMPANY_ID: agent.companyId,
   };
-  const apiUrl = process.env.PAPERCLIP_API_URL ?? `http://localhost:${process.env.PORT ?? 3100}`;
+  const runtimeHost = resolveHostForUrl(
+    process.env.PAPERCLIP_LISTEN_HOST ?? process.env.HOST ?? "localhost",
+  );
+  const runtimePort = process.env.PAPERCLIP_LISTEN_PORT ?? process.env.PORT ?? "3100";
+  const apiUrl = process.env.PAPERCLIP_API_URL ?? `http://${runtimeHost}:${runtimePort}`;
   vars.PAPERCLIP_API_URL = apiUrl;
   return vars;
 }
diff --git a/server/src/__tests__/paperclip-env.test.ts b/server/src/__tests__/paperclip-env.test.ts
new file mode 100644
index 00000000..1a65d9e9
--- /dev/null
+++ b/server/src/__tests__/paperclip-env.test.ts
@@ -0,0 +1,58 @@
+import { afterEach, describe, expect, it } from "vitest";
+import { buildPaperclipEnv } from "../adapters/utils.js";
+
+const ORIGINAL_PAPERCLIP_API_URL = process.env.PAPERCLIP_API_URL;
+const ORIGINAL_PAPERCLIP_LISTEN_HOST = process.env.PAPERCLIP_LISTEN_HOST;
+const ORIGINAL_PAPERCLIP_LISTEN_PORT = process.env.PAPERCLIP_LISTEN_PORT;
+const ORIGINAL_HOST = process.env.HOST;
+const ORIGINAL_PORT = process.env.PORT;
+
+afterEach(() => {
+  if (ORIGINAL_PAPERCLIP_API_URL === undefined) delete process.env.PAPERCLIP_API_URL;
+  else process.env.PAPERCLIP_API_URL = ORIGINAL_PAPERCLIP_API_URL;
+
+  if (ORIGINAL_PAPERCLIP_LISTEN_HOST === undefined) delete process.env.PAPERCLIP_LISTEN_HOST;
+  else process.env.PAPERCLIP_LISTEN_HOST = ORIGINAL_PAPERCLIP_LISTEN_HOST;
+
+  if (ORIGINAL_PAPERCLIP_LISTEN_PORT === undefined) delete process.env.PAPERCLIP_LISTEN_PORT;
+  else process.env.PAPERCLIP_LISTEN_PORT = ORIGINAL_PAPERCLIP_LISTEN_PORT;
+
+  if (ORIGINAL_HOST === undefined) delete process.env.HOST;
+  else process.env.HOST = ORIGINAL_HOST;
+
+  if (ORIGINAL_PORT === undefined) delete process.env.PORT;
+  else process.env.PORT = ORIGINAL_PORT;
+});
+
+describe("buildPaperclipEnv", () => {
+  it("prefers an explicit PAPERCLIP_API_URL", () => {
+    process.env.PAPERCLIP_API_URL = "http://localhost:4100";
+    process.env.PAPERCLIP_LISTEN_HOST = "127.0.0.1";
+    process.env.PAPERCLIP_LISTEN_PORT = "3101";
+
+    const env = buildPaperclipEnv({ id: "agent-1", companyId: "company-1" });
+
+    expect(env.PAPERCLIP_API_URL).toBe("http://localhost:4100");
+  });
+
+  it("uses runtime listen host/port when explicit URL is not set", () => {
+    delete process.env.PAPERCLIP_API_URL;
+    process.env.PAPERCLIP_LISTEN_HOST = "0.0.0.0";
+    process.env.PAPERCLIP_LISTEN_PORT = "3101";
+    process.env.PORT = "3100";
+
+    const env = buildPaperclipEnv({ id: "agent-1", companyId: "company-1" });
+
+    expect(env.PAPERCLIP_API_URL).toBe("http://localhost:3101");
+  });
+
+  it("formats IPv6 hosts safely in fallback URL generation", () => {
+    delete process.env.PAPERCLIP_API_URL;
+    process.env.PAPERCLIP_LISTEN_HOST = "::1";
+    process.env.PAPERCLIP_LISTEN_PORT = "3101";
+
+    const env = buildPaperclipEnv({ id: "agent-1", companyId: "company-1" });
+
+    expect(env.PAPERCLIP_API_URL).toBe("http://[::1]:3101");
+  });
+});
diff --git a/server/src/index.ts b/server/src/index.ts
index 2eef0c31..5cf414da 100644
--- a/server/src/index.ts
+++ b/server/src/index.ts
@@ -434,6 +434,15 @@ if (listenPort !== config.port) {
   logger.warn(`Requested port is busy; using next free port (requestedPort=${config.port}, selectedPort=${listenPort})`);
 }
 
+const runtimeListenHost = config.host;
+const runtimeApiHost =
+  runtimeListenHost === "0.0.0.0" || runtimeListenHost === "::"
+    ? "localhost"
+    : runtimeListenHost;
+process.env.PAPERCLIP_LISTEN_HOST = runtimeListenHost;
+process.env.PAPERCLIP_LISTEN_PORT = String(listenPort);
+process.env.PAPERCLIP_API_URL = `http://${runtimeApiHost}:${listenPort}`;
+
 setupLiveEventsWebSocketServer(server, db as any, {
   deploymentMode: config.deploymentMode,
   resolveSessionFromHeaders,