Workers

Extension gateway

The gateway between the Ultron browser extension and the rest of the platform. Each connected user has their own Durable Object instance holding extension state: open tabs, queued events, current selection, last command. Acts as a thin authenticated proxy so the extension never has direct credentials for downstream surfaces.

Updated today

Overview

At a glance

Worker: extension-gateway
Durable Object: UserExtensionDO
DO key: (user_id, extension_session)
Purpose: Proxy + per-user state for the browser extension
Auth: Short-lived tokens issued by edge-auth, validated per call

Worker shape

wrangler.toml (key bindings)toml

1name = "extension-gateway"

2main = "src/index.ts"

4[[durable_objects.bindings]]

5class_name = "UserExtensionDO"

6name = "USER_EXT"

8[vars]

9APP_ORIGIN = "https://app.51ultron.com"

UserExtensionDO

One DO per connected user.

src/index.ts (DO sketch)ts

1export class UserExtensionDO {

2 // Storage keys:

3 // open_tabs : Array<TabInfo> (most-recent first, capped at 32)

4 // queued_events : Array<EventMsg> (drained on each /flush)

5 // last_selection : { text, url, ts }

6 // pinned_brain_notes : Array<NoteRef> (extension can pin notes for quick access)

8 async fetch(req: Request) {

9 // Routes:

10 // POST /report-tab update open_tabs

11 // POST /report-selection update last_selection

12 // POST /queue enqueue event

13 // GET /flush drain queued_events, return JSON

14 // POST /act run a chat-v2 invocation (proxy)

15 // GET /state read snapshot of DO state

16 }

17}

Note

The DO is the single source of truth for the extension's state. A page reload in the browser does not lose anything; the next ping pulls the state back from the DO.

Endpoints

Method + path	Body	Returns
POST /report-tab	{ tabId, url, title, ts }	ok
POST /report-selection	{ text, url, ts }	ok
POST /queue	{ kind, payload }	ok (event queued)
GET /flush	-	Array of queued events; clears the queue
POST /act	{ prompt, scopes? }	Streams the chat-v2 response back to the extension
GET /state	-	Snapshot of DO state for diagnostics
POST /pin-note	{ noteId }	Pin a brain note for quick access

Per-tab session state

The extension reports tab events into the gateway so the DO always knows what page the user is looking at. When the user invokes the extension, the gateway can build context from current tab + recent tabs without an extra round trip to the browser. This makes "summarise this page" or "save this contact to leads" actions fast and stateless on the extension side.

State key	Updated by	Used by
open_tabs	POST /report-tab	POST /act when the prompt needs current-tab context
last_selection	POST /report-selection	POST /act for selection-driven prompts
queued_events	POST /queue	GET /flush from a follow-up extension call
pinned_brain_notes	POST /pin-note	POST /act injects pinned notes as context

File map

cf-workers/extension-gateway

wrangler.toml

src

index.tsDO class, route table, app proxy

auth.tstoken validation against edge-auth

act.tsstreaming proxy to chat-v2