diff --git a/apps/pi-extension/server/network.test.ts b/apps/pi-extension/server/network.test.ts
index c261b32b..174e7157 100644
--- a/apps/pi-extension/server/network.test.ts
+++ b/apps/pi-extension/server/network.test.ts
@@ -1,5 +1,5 @@
 import { afterEach, describe, expect, test } from "bun:test";
-import { getServerPort, isRemoteSession } from "./network";
+import { getServerHostname, getServerPort, isRemoteSession } from "./network";
 
 const savedEnv: Record<string, string | undefined> = {};
 const envKeys = ["PLANNOTATOR_REMOTE", "PLANNOTATOR_PORT", "SSH_TTY", "SSH_CONNECTION"];
@@ -94,3 +94,16 @@ describe("pi port selection", () => {
 		expect(getServerPort()).toEqual({ port: 9999, portSource: "env" });
 	});
 });
+
+describe("pi server hostname", () => {
+	test("binds local sessions to loopback", () => {
+		clearEnv();
+		expect(getServerHostname()).toBe("127.0.0.1");
+	});
+
+	test("binds remote sessions to all interfaces", () => {
+		clearEnv();
+		process.env.PLANNOTATOR_REMOTE = "1";
+		expect(getServerHostname()).toBe("0.0.0.0");
+	});
+});
diff --git a/apps/pi-extension/server/network.ts b/apps/pi-extension/server/network.ts
index 1399aa05..522f4ef5 100644
--- a/apps/pi-extension/server/network.ts
+++ b/apps/pi-extension/server/network.ts
@@ -8,6 +8,7 @@ import type { Server } from "node:http";
 import { release } from "node:os";
 
 const DEFAULT_REMOTE_PORT = 19432;
+const LOOPBACK_HOST = "127.0.0.1";
 
 /**
  * Check if running in a remote session (SSH, devcontainer, etc.)
@@ -67,6 +68,10 @@ export function getServerPort(): {
 	return { port: 0, portSource: "random" };
 }
 
+export function getServerHostname(): string {
+	return isRemoteSession() ? "0.0.0.0" : LOOPBACK_HOST;
+}
+
 const MAX_RETRIES = 5;
 const RETRY_DELAY_MS = 500;
 
@@ -81,7 +86,7 @@ export async function listenOnPort(
 				server.once("error", reject);
 				server.listen(
 					result.port,
-					isRemoteSession() ? "0.0.0.0" : "127.0.0.1",
+					getServerHostname(),
 					() => {
 						server.removeListener("error", reject);
 						resolve();
diff --git a/packages/server/annotate.ts b/packages/server/annotate.ts
index 7d913c55..13865f2a 100644
--- a/packages/server/annotate.ts
+++ b/packages/server/annotate.ts
@@ -11,7 +11,7 @@
  *   PLANNOTATOR_PORT   - Fixed port to use (default: random locally, 19432 for remote)
  */
 
-import { isRemoteSession, getServerPort } from "./remote";
+import { isRemoteSession, getServerHostname, getServerPort } from "./remote";
 import { getRepoInfo } from "./repo";
 import type { Origin } from "@plannotator/shared/agents";
 import { handleImage, handleUpload, handleServerReady, handleDraftSave, handleDraftLoad, handleDraftDelete, handleFavicon } from "./shared-handlers";
@@ -131,6 +131,7 @@ export async function startAnnotateServer(
   for (let attempt = 1; attempt <= MAX_RETRIES; attempt++) {
     try {
       server = Bun.serve({
+        hostname: getServerHostname(),
         port: configuredPort,
 
         async fetch(req, server) {
diff --git a/packages/server/index.ts b/packages/server/index.ts
index 91f01f5d..d2c416aa 100644
--- a/packages/server/index.ts
+++ b/packages/server/index.ts
@@ -11,7 +11,7 @@
 
 import type { Origin } from "@plannotator/shared/agents";
 import { resolve } from "path";
-import { isRemoteSession, getServerPort } from "./remote";
+import { isRemoteSession, getServerHostname, getServerPort } from "./remote";
 import { openEditorDiff } from "./ide";
 import {
   saveToObsidian,
@@ -200,6 +200,7 @@ export async function startPlannotatorServer(
   for (let attempt = 1; attempt <= MAX_RETRIES; attempt++) {
     try {
       server = Bun.serve({
+        hostname: getServerHostname(),
         port: configuredPort,
 
         async fetch(req, server) {
diff --git a/packages/server/remote.test.ts b/packages/server/remote.test.ts
index 6cc4eba9..bdf6840d 100644
--- a/packages/server/remote.test.ts
+++ b/packages/server/remote.test.ts
@@ -5,7 +5,7 @@
  */
 
 import { afterEach, describe, expect, test } from "bun:test";
-import { isRemoteSession, getServerPort } from "./remote";
+import { isRemoteSession, getServerHostname, getServerPort } from "./remote";
 
 // Save and restore env between tests
 const savedEnv: Record<string, string | undefined> = {};
@@ -135,3 +135,16 @@ describe("getServerPort", () => {
     expect(getServerPort()).toBe(0);
   });
 });
+
+describe("getServerHostname", () => {
+  test("returns loopback for local sessions", () => {
+    clearEnv();
+    expect(getServerHostname()).toBe("127.0.0.1");
+  });
+
+  test("returns all interfaces for remote sessions", () => {
+    clearEnv();
+    process.env.PLANNOTATOR_REMOTE = "1";
+    expect(getServerHostname()).toBe("0.0.0.0");
+  });
+});
diff --git a/packages/server/remote.ts b/packages/server/remote.ts
index 379afca0..64d84f6e 100644
--- a/packages/server/remote.ts
+++ b/packages/server/remote.ts
@@ -9,6 +9,7 @@
  */
 
 const DEFAULT_REMOTE_PORT = 19432;
+const LOOPBACK_HOST = "127.0.0.1";
 
 function getRemoteOverride(): boolean | null {
   const remote = process.env.PLANNOTATOR_REMOTE;
@@ -63,3 +64,11 @@ export function getServerPort(): number {
   // Remote sessions use fixed port for port forwarding; local uses random
   return isRemoteSession() ? DEFAULT_REMOTE_PORT : 0;
 }
+
+/**
+ * Bind local sessions to loopback, but keep remote sessions reachable via the
+ * container or host network interface for SSH/devcontainer/Docker forwarding.
+ */
+export function getServerHostname(): string {
+  return isRemoteSession() ? "0.0.0.0" : LOOPBACK_HOST;
+}
diff --git a/packages/server/review.ts b/packages/server/review.ts
index 4c785c8f..c6b98ac0 100644
--- a/packages/server/review.ts
+++ b/packages/server/review.ts
@@ -9,7 +9,7 @@
  *   PLANNOTATOR_PORT   - Fixed port to use (default: random locally, 19432 for remote)
  */
 
-import { isRemoteSession, getServerPort } from "./remote";
+import { isRemoteSession, getServerHostname, getServerPort } from "./remote";
 import type { Origin } from "@plannotator/shared/agents";
 import { type DiffType, type GitContext, runVcsDiff, getVcsFileContentsForDiff, canStageFiles, stageFile, unstageFile, resolveVcsCwd, validateFilePath } from "./vcs";
 import { getRepoInfo } from "./repo";
@@ -348,6 +348,7 @@ export async function startReviewServer(
   for (let attempt = 1; attempt <= MAX_RETRIES; attempt++) {
     try {
       server = Bun.serve({
+        hostname: getServerHostname(),
         port: configuredPort,
 
         async fetch(req, server) {