Actually - What Markets Really Think

A Chrome extension and an MCP server that put prediction-market odds on top of

the news you are already reading.

News tells you that "experts are concerned" or that "odds are rising". It

rarely tells you a number. The number exists - on a prediction market, where

people are betting their own money on the outcome. It just lives in another

tab, and finding it means knowing such a market exists in the first place.

Actually closes that gap. Open an article, click the toolbar icon, and the

extension matches the text against live Polymarket markets and shows the

market's own probability. No account, no wallet, no signup.

What it does

• Matches an article to a market. A local embedding model

(`Xenova/all-MiniLM-L12-v2`, ~33 MB) scores the article text against the

cached market set, boosted by keyword and number overlap - numbers matter

because the encoder is nearly blind to them, and "dip to $57,500" embeds

almost identically to "reach $120,000".

• Runs on your device. Model and WASM runtime are bundled at build time -

nothing is fetched from a CDN at install or runtime, and on the default

settings the article text never leaves the machine.

• Reads non-English pages. They are translated to English before matching,

using Chrome's own built-in `Translator` API (local, no network). Every

Polymarket question is written in English, and the local model holds 86

Cyrillic tokens out of 30522 - an untranslated Russian headline embeds to

noise. Translated, the same headline scores 0.53-0.71 against the market it

is actually about, against a 0.35 floor.

• Trades, optionally. Connect any WalletConnect v2 wallet for limit and

market orders, selling, cancelling resting orders, and a positions panel with

cost basis and P&L. Keys and funds are never held by us.

• Serves agents too. The same capabilities are exposed over the Model

Context Protocol: `check_news`, `get_market`, `place_order`, `sell_order`,

`cancel_order`, `get_positions`.

Using the MCP server

The MCP server is published, so it needs no clone and no build. Add it to any

MCP client (Claude Desktop, Cursor, and anything else that speaks the

protocol):

{
  "mcpServers": {
    "actually": {
      "command": "npx",
      "args": ["actually-mcp-server"]
    }
  }
}

That gives an agent the signal tools - `check_news` and `get_market` - with no

key and no wallet. Ask it "what do markets think about this?" with a headline

and it answers with the market's own price.

Trading tools appear only if you supply a key of your own:

"env": {
  "POLYMARKET_PRIVATE_KEY": "0x...",
  "ACTUALLY_MAX_ORDER_USD": "100",
  "ACTUALLY_DAILY_LIMIT_USD": "500"
}

Both caps are enforced server-side against a persisted spend ledger, so an

agent cannot talk its way past them by claiming a different price.

`redeem_position` needs a further explicit opt-in

(`ACTUALLY_ENABLE_REDEEM=true`) because it submits a real on-chain transaction

and is still in testing.

Full documentation, including every environment variable and the reasoning

behind the guards: `packages/mcp-server/README.md`.

Listed in the official MCP registry

as `io.github.Sofiia7/actually`, on mcpservers.org, and on Glama:

How it fits together

extension/            Chrome MV3 extension (React popup, offscreen document)
extension/worker/     Cloudflare Worker - API proxy, rate limiting, market cache
packages/core/        Matching, pricing and Polymarket API logic, shared by both clients
packages/mcp-server/  MCP server, published to npm as actually-mcp-server
packages/market-cache-builder/   Cron job that precomputes the market embeddings

The heavy work lives in an offscreen document because MV3 service workers

cannot run WASM, hold a WebSocket, or survive long enough to sign an order.

The market cache is 2000 open markets with precomputed embeddings, rebuilt

every two hours. Selection blends three orderings - 24h volume, lifetime

volume, and recency - because ranking by lifetime volume alone is the wrong

shelf for a news tool: a market opened this morning under today's headline has

no history and loses to a year-old election market every time.

The Worker exists so no client has to hold a credential. It proxies

Polymarket's APIs, serves the precomputed cache, and acts as a remote signer

for the relayer, so the builder credential stays on the server and never ships

inside an extension.

Running it

npm install
npm run models:fetch -w extension   # bundle the embedding model
npm run build -w extension          # type-check + build to extension/dist

Load `extension/dist` as an unpacked extension in Chrome. Copy

`extension/.env.example` to `.env.local` and fill it in first - the build bakes

the Worker URL, the WalletConnect project id and the builder code.

npm test --workspaces               # 686 tests across four workspaces

Privacy

Discovery is free and needs no account. There are no content scripts: the page

is read only when you click, and only the active tab. On the default settings

(local embeddings, translation off-device) the article text does not leave your

machine. Telemetry is opt-in and off by default.

Full policy: https://actually-api.sofiaseremeteva.workers.dev/privacy

Status

The extension is built and passing its release gates; the Chrome Web Store

submission is in progress. `actually-mcp-server` is published on npm and listed

in the official MCP registry.

Redeeming a resolved position is in testing: builder authentication,

neg-risk contract selection and the zero-balance guard are each verified

against live services, but no redeem has yet been observed collecting funds end

to end.

Trading is unavailable in several jurisdictions (US, GB, FR, BE, AU, SG, TH,

TW, PL, and sanctioned countries), enforced Worker-side. Viewing odds works

everywhere.

Actually does not provide financial advice.

License

See LICENSE.