Reach120 MCP server
An MCP server that gives an AI agent a governed
path to the Reach120 TOEFL iBT practice API: fetch
Writing practice prompts, and score a learner's written response.
Reach120 is an independent practice platform. It is not affiliated with, endorsed
by, or administered by ETS. TOEFL® is a registered trademark of ETS. Reach120 is
not affiliated with, endorsed by, or approved by ETS.
| Tool | What it does | Cost |
|---|
list_practice_prompts | List Writing practice prompts, with the id used to score against one | Reads stored rows, runs no model |
get_practice_prompt | Fetch one prompt with its full scenario or discussion context | Reads a stored row, runs no model |
score_writing_response | Score a written response, returning an automated practice score and a short rationale | Runs the scorer; metered against your key |
You bring the key
This server carries no credential. It forwards the key you place in
REACH120_API_KEY and returns the API's answer unchanged.
That is a design decision, not an omission. Every limit that matters lives on the
server side of the API and is evaluated on every call — a per-key request window,
a per-key daily scoring allowance, and a service-wide spending gate. A client that
enforced its own limits would only be enforcing them on people who chose to keep
using the client, so this one enforces none and cannot be a way around any of
them. Delete this package and call the endpoint directly and you get identical
refusals.
There is no unauthenticated scoring path. An agent with no key receives a refusal
naming where a key comes from, and nothing is sent.
Request a key and read the full limit, error-code and version policy at
https://www.reach120.com/developers.
Install
This package is not published on npm. The install path is this repository, and
it is the only one — @reach120/mcp-server does not resolve on the public npm
registry and no other package name stands in for it.
npx -y github:reach120/reach120-mcp
npm compiles the TypeScript during that install through the prepare script, so
there is no separate build step.
Or clone it and run it from source:
git clone https://github.com/reach120/reach120-mcp.git
cd reach120-mcp
npm install
npm run build
node dist/index.js
Claude Desktop (claude_desktop_config.json), Claude Code, or any MCP client that
speaks stdio:
{
"mcpServers": {
"reach120": {
"command": "npx",
"args": ["-y", "github:reach120/reach120-mcp"],
"env": {
"REACH120_API_KEY": "r120_live_your_key_here"
}
}
}
}
| Variable | Required | Default | Meaning |
|---|
REACH120_API_KEY | yes | — | Your Reach120 API key. Tools refuse without it. |
REACH120_API_BASE_URL | no | https://www.reach120.com | Point at another deployment. |
REACH120_API_TIMEOUT_MS | no | see readConfig in src/api.ts | Per-request timeout, in milliseconds. |
What a refusal looks like
Limits refuse with a machine-readable code rather than degrading. A call that hits
the key's daily allowance is not quietly scored on a cheaper engine and handed back
as if it were the engine you asked for — the code names what happened, and the
error table on /developers says what each one means.
Verify it locally
npm install
npm run build
npm run verify
npm run verify starts the built server over stdio, completes a real MCP
handshake with the SDK client, prints the advertised tools, and calls one tool
without a key to show the refusal path.
Scores are practice feedback
score_writing_response returns automated practice feedback produced by Reach120.
It is not an ETS score and is not reported on the official scale. This README
deliberately does not name the scale the number is on: that fact is published
beside a mandatory limitation the claims ledger requires, which a package page
cannot render. The response shape is documented on
https://www.reach120.com/developers.
TOEFL® is a registered trademark of ETS. Reach120 is not affiliated with, endorsed
by, or approved by ETS.
Licence
MIT. See LICENSE.