Newton Browser MCP server

Newton Browser

Newton Browser is a local MCP browser-control product for agents. Each session launches an isolated Chrome or Edge process and controls it through inherited private CDP pipes. By default browser traffic uses Chromium's normal networking with no Newton proxy, origin allowlist, request interception, or resource filtering.

The default runtime requires no browser extension, relay, daemon, debug TCP port, database, telemetry, hosted service, or model-provider integration.

Status

The default source runtime now uses the replacement shared engine, with isolated workers from a shared Newton login source and an optional thin existing-browser adapter. Native actions, precise editing, contextual controls, records/documents, screenshots, tab ownership and update foundations are implemented. This is an unreleased development checkpoint, not completed real-world acceptance.

The legacy direct runtime is retired (2026-09-25): the session engine is the only action, receipt and ref authority. Build, typecheck, boundary lint and the full suite pass. Feedback/reading refinements, platform and authenticated task QA, and three unchanged packed release gates remain open. See the current progress ledger, remaining roadmap and consolidation record.

Package version remains 0.6.4; historical receipts apply only to their recorded candidates. No package or browser-store release is implied by the source checkpoint.

Newton implements only stateless MCP 2026-07-28 over newline-delimited stdio JSON. Clients send protocol version and capabilities in every request. Newton exposes no legacy handshake or framing mode.

Requirements

• Node.js 24 or newer.
• A current local Chrome or Edge installation.
• An MCP client that supports MCP 2026-07-28, local stdio servers, and image content.

Build and connect

pnpm install --frozen-lockfile
pnpm build
node apps/mcp-server/dist/index.js doctor --live

That is enough for ephemeral sessions: Newton discovers Chrome or Edge and creates a fresh isolated identity per session. Optional setup only selects a default browser:

node apps/mcp-server/dist/index.js setup --browser chrome

Every owned session is an isolated copy of a shared login source (default unless the session names another). To sign in once for later sessions, open the source's visible browser, sign in personally, and confirm:

node apps/mcp-server/dist/index.js source login --id default --browser chrome

Newton never asks an agent to enter or retrieve credentials. The published sign-in becomes the source's next generation; running sessions keep their own copies, and nothing a session does is merged back.

MCP configuration

{
  "mcpServers": {
    "newton-browser": {
      "command": "node",
      "args": ["C:\\absolute\\path\\newton-browser\\apps\\mcp-server\\dist\\index.js"]
    }
  }
}

The local installer can update Codex configuration or print a generic entry:

node apps/mcp-server/dist/index.js install codex --dry-run
node apps/mcp-server/dist/index.js install generic

Codex installation enables Codex's mcp20260728 feature, pins CODEXMCPPROTOCOLVERSION=2026-07-28, and verifies the exact candidate's live stateless discovery, self-reported package version, and required browser-tool catalog before atomically replacing its configuration. The resulting entrypoint/version pair is pinned; incompatible or stale candidates cannot displace a working install.

Agent workflow

Shortened. The full README is on GitHub.