Execution Delivery Harness

Controlled delivery of agent actions into user-owned execution environments. The current reference implementation connects ChatGPT/MCP to explicitly shared browser pages, with Job Search OS as the first real-world consumer. By Daniel Chechik. Independent of Mozilla, OpenAI, LinkedIn, Google and Opera.

Version 0.1.1

Firefox extension + local Node.js companion. Four read-only tools: list_tabs, read_page, find_in_page, bridge_status. Use it for visible job listings and recruiter conversations, including LinkedIn pages you already have open. The bridge does not log in, crawl message history, send messages or submit applications. Only loaded main-document text is read.

Each page is shared from the toolbar for 30 minutes. Navigation, reload, tab closure, extension restart and manual revocation end access. Unshared tabs are not listed. No browser history, cookie API, raw profile or form-draft export.

Related MCP server: ff-mcp

Quickstart

Requires Firefox 140+ and Node.js 22+. The companion is a separate installation:

git clone https://github.com/dzzk-r/execution-delivery-harness.git
cd execution-delivery-harness
npm ci
npm start

Load firefox/manifest.json using Firefox about:debugging → This Firefox → Load Temporary Add-on. Temporary installation ends when Firefox restarts. For permanent installation, Mozilla must sign the submitted package.

Paste the companion's extension pairing token into the extension settings and accept the data-flow disclosure. Keep that token out of chats and screenshots. Open the toolbar button and check that the companion is Connected.

ChatGPT

Installing the extension alone does not connect ChatGPT. ChatGPT needs a supported developer-mode MCP connection to the companion. For a public HTTPS transport, set PUBLIC_URL to your tunnel's stable HTTPS origin before starting npm start, and point the tunnel at http://127.0.0.1:43119. Connect ChatGPT to https://YOUR-ORIGIN/mcp with OAuth / dynamic client registration. Keep the companion bound to loopback. Alternatively a supported private MCP tunnel can reach the local server; availability depends on your account and workspace.

During OAuth linking, open the extension popup and approve the displayed client and callback origin. Then open your job page and click Share this page. Ask the client to list shared tabs, read one by its opaque handle, or find text. Stop sharing to block subsequent reads. Disconnect also revokes client tokens.

The browser path has no required paid automation service. ChatGPT, hosting and transport providers have their own account, plan and availability requirements.

Stop and approval controls

In the extension popup, use Pause all actions to stop every client, cancel queued or in-flight requests, and remove page grants. Resume does not restore grants; share each page again. Local pause stays effective if the companion is unavailable.

Each authorized client has four permission selectors: list shared pages, read page text, find passages and check connection. Allow performs that operation within existing page grants. Ask every time holds each request until you choose Allow once or Deny once in Firefox; an approval is never reused. Block refuses that operation until you change it. New authorized clients default to Allow after the explicit connection approval. Choose Ask or Block before sharing pages if desired.

Only extension UI can change these settings; MCP client credentials cannot. Policies persist in the local companion and survive reauthorization of the same registered client. A newly registered client needs fresh connection approval. Revoking a connection removes its tokens. Stop and revoke cannot retract data already returned to a client. ChatGPT's own plugin approval settings are an additional, independent control.

Development

npm test
npm run lint
npm run build
FIREFOX_BIN=/path/to/firefox npm run test:firefox

dist/dzzk_job_search_os_browser_bridge-0.1.1.zip is the unsigned AMO submission package. An unsigned ZIP is not an approved AMO release. Firefox smoke testing uses a disposable profile and synthetic pages, never personal browser sessions.

Boundaries and next adapters

Privacy · Security · Controls · Compatibility · AMO submission.

Chrome/Chromium, Opera, Safari and site-specific adapters are later work. The existing Opera Browser Connector remains an independent third-party option. No Chrome, Opera or Safari adapter support in this release is claimed. Other websites can be manually shared as ordinary pages; dedicated extraction and end-to-end compatibility need testing.

MIT license. Support: GitHub issues. Do not post private browser data or tokens.