docs(teleportation): update build instructions and add trajectory_teleporter.ts

packages/core/src/teleportation/TELEPORTATION.md

@@ -69,11 +69,27 @@ compatibility.
 
 To keep the CLI up to date:
 
-1. Update `trajectory_teleporter.ts` in the Antigravity workspace.
-2. Re-bundle using `esbuild` or a similar tool to produce a new
-   `trajectory_teleporter.min.js`.
-3. Copy the new `.min.js` into `packages/core/src/teleportation/`.
-4. Rebuild the Gemini CLI.
+1. Update `packages/core/src/teleportation/trajectory_teleporter.ts` with any
+   logic changes.
+2. To build a new minified bundle, you must run it from within the Antigravity
+   `Exafunction` workspace because it depends on the complex Protobuf schema
+   definitions there
+   (`exa/proto_ts/dist/exa/gemini_coder/proto/trajectory_pb.js`).
+3. If the Protobuf JS definitions haven't been generated in your `Exafunction`
+   project yet, build them first:
+   ```bash
+   pnpm --dir exa/proto_ts build
+   ```
+4. Inside the `Exafunction` project root, run:
+   ```bash
+   pnpm dlx esbuild /path/to/orions-belt/packages/core/src/teleportation/trajectory_teleporter.ts \
+     --bundle \
+     --minify \
+     --format=esm \
+     --platform=node \
+     --outfile=/path/to/orions-belt/packages/core/src/teleportation/trajectory_teleporter.min.js
+   ```
+5. Verify the new `trajectory_teleporter.min.js` works locally in the CLI.
 
 > [!TIP] In the long term, this logic could be moved to a shared NPM package
 > published from the Antigravity repository, allowing the Gemini CLI to stay

packages/core/src/teleportation/trajectory_teleporter.ts

@@ -0,0 +1,72 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+// @ts-nocheck
+import * as crypto from 'node:crypto';
+import { Trajectory } from './exa/proto_ts/dist/exa/gemini_coder/proto/trajectory_pb.js';
+
+const DEFAULT_KEY = Buffer.from('safeCodeiumworldKeYsecretBalloon');
+const NONCE_SIZE = 12; // GCM default nonce size
+const TAG_SIZE = 16; // GCM default tag size
+
+/**
+ * Decrypts data using AES-256-GCM.
+ * The data is expected to be in the format: [nonce (12b)][ciphertext][tag (16b)]
+ */
+export function decrypt(data: Buffer, key: Buffer = DEFAULT_KEY): Buffer {
+  if (data.length < NONCE_SIZE + TAG_SIZE) {
+    throw new Error('Data too short');
+  }
+
+  const nonce = data.subarray(0, NONCE_SIZE);
+  const tag = data.subarray(data.length - TAG_SIZE);
+  const ciphertext = data.subarray(NONCE_SIZE, data.length - TAG_SIZE);
+
+  const decipher = crypto.createDecipheriv('aes-256-gcm', key, nonce);
+  decipher.setAuthTag(tag);
+
+  return Buffer.concat([decipher.update(ciphertext), decipher.final()]);
+}
+
+/**
+ * Encrypts data using AES-256-GCM.
+ * Returns data in the format: [nonce (12b)][ciphertext][tag (16b)]
+ */
+export function encrypt(data: Buffer, key: Buffer = DEFAULT_KEY): Buffer {
+  const nonce = crypto.randomBytes(NONCE_SIZE);
+  const cipher = crypto.createCipheriv('aes-256-gcm', key, nonce);
+
+  const ciphertext = Buffer.concat([cipher.update(data), cipher.final()]);
+  const tag = cipher.getAuthTag();
+
+  return Buffer.concat([nonce, ciphertext, tag]);
+}
+
+/**
+ * Converts Antigravity binary trajectory to JSON.
+ */
+export function trajectoryToJson(data: Buffer): unknown {
+  let pbData: Buffer;
+  try {
+    // Try to decrypt first
+    pbData = decrypt(data);
+  } catch (_e) {
+    // Fallback to plain protobuf if decryption fails
+    pbData = data;
+  }
+
+  const trajectory = Trajectory.fromBinary(pbData);
+  return trajectory.toJson();
+}
+
+/**
+ * Converts JSON to Antigravity binary trajectory (encrypted).
+ */
+export function jsonToTrajectory(json: unknown): Buffer {
+  const trajectory = Trajectory.fromJson(json, { ignoreUnknownFields: true });
+  const pbData = Buffer.from(trajectory.toBinary());
+  return encrypt(pbData);
+}