# proofread-mcp

An MCP server for [proofread.law](https://proofread.law). It lets Claude Desktop, Claude Code, Cursor and the OpenAI Agents SDK check US case citations before a draft is filed.

proofread.law checks each citation against an open register of about 10 million court opinions (CourtListener bulk data). Every result says what was checked, what was found, and what the register cannot see.

## What it does

Six tools:

| Tool | Input | What comes back |
|---|---|---|
| `check_citations` | text, `deep` (optional) | The coverage statement, counts per tier, one line per row that needs a human, the number of citations found, a report id |
| `check_document` | path to a `.pdf`, `.docx` or `.txt` (up to 10 MB), `deep` (optional) | The same, for a file on disk |
| `resolve_citation` | one citation string | The register's answer for that citation: found (case, court, date, parallel citations, link), ambiguous (candidates), not in the register, cannot verify, known citation, or no citation recognised; the coverage of that volume; the coverage statement |
| `resolve_citations` | a list of up to 500 citation strings | Counts by status, one line per citation in input order, the coverage statement |
| `coverage` | nothing | The coverage statement and the storage notice |
| `render_report` | a report id from a previous check, or the full report JSON | A markdown diligence report |

`check_citations` and `check_document` read prose: they compare the case name and any quotation with the register. `resolve_citation` and `resolve_citations` look the citation string up in the register (the `/v1/resolve` API) and tell you which case sits there; they do not compare it with the name you have.

Tiers, in the words the tools use:

| Tier | Word | Meaning |
|---|---|---|
| red | check this | The register holds something concrete that disagrees: a different case at that citation, a volume or page that does not match, quoted words not in the opinion |
| orange | cannot verify | Nothing to check against: a Westlaw or Lexis identifier, a volume newer than the register, a reporter the register holds only in part. Not evidence either way |
| green | found | The citation resolves to a case whose caption matches |
| white | deep check | With `deep: true` only: whether the opinion supports the sentence it is cited for. A review queue, not a verdict |

What it cannot do: resolve Westlaw (WL) or Lexis identifiers, check statutes, regulations or secondary sources, or say whether a case is still good law. Those limits are stated in every tool description and in the coverage statement that comes with every result.

## Install

Needs Node 20 or newer. No install step is required; `npx` fetches it.

Until the package is on npm, clone this repository, run `npm install && npm run build`, and use `node /absolute/path/to/proofread-mcp/dist/cli.js` wherever the snippets below say `npx -y proofread-mcp`.

### Claude Desktop

Edit `claude_desktop_config.json` (Settings, Developer, Edit Config):

```json
{
  "mcpServers": {
    "proofread": {
      "command": "npx",
      "args": ["-y", "proofread-mcp"],
      "env": {
        "PROOFREAD_API_KEY": "pl_..."
      }
    }
  }
}
```

Leave out `env` to use the free tier.

### Claude Code

```bash
claude mcp add proofread -- npx -y proofread-mcp
# with a Firm key:
claude mcp add proofread -e PROOFREAD_API_KEY=pl_... -- npx -y proofread-mcp
```

### Cursor

Settings, MCP, Add new global MCP server, or write `.cursor/mcp.json` in the project:

```json
{
  "mcpServers": {
    "proofread": {
      "command": "npx",
      "args": ["-y", "proofread-mcp"],
      "env": { "PROOFREAD_API_KEY": "pl_..." }
    }
  }
}
```

### OpenAI Agents SDK (over HTTP)

Start the server with the HTTP transport:

```bash
PROOFREAD_API_KEY=pl_... npx proofread-mcp --http --port 3333
# MCP endpoint: http://127.0.0.1:3333/mcp   health: http://127.0.0.1:3333/health
```

Then connect from the Agents SDK:

```python
from agents import Agent, Runner
from agents.mcp import MCPServerStreamableHttp

async with MCPServerStreamableHttp(params={"url": "http://127.0.0.1:3333/mcp"}) as proofread:
    agent = Agent(name="Drafting assistant", instructions="Check every case citation before you rely on it.", mcp_servers=[proofread])
    result = await Runner.run(agent, "Check the citations in this paragraph: ...")
```

```ts
import { Agent, run, MCPServerStreamableHttp } from "@openai/agents";

const proofread = new MCPServerStreamableHttp({ url: "http://127.0.0.1:3333/mcp", name: "proofread" });
await proofread.connect();
const agent = new Agent({ name: "Drafting assistant", mcpServers: [proofread] });
const result = await run(agent, "Check the citations in this paragraph: ...");
```

The HTTP server binds to 127.0.0.1 by default. To expose it on a network use `--host 0.0.0.0` and put it behind something that adds authentication; the server has none of its own.

### Any MCP client

stdio: run `proofread-mcp`. Streamable HTTP: run `proofread-mcp --http --port 3333` and point the client at `/mcp`.

## Environment variables

| Variable | Default | Meaning |
|---|---|---|
| `PROOFREAD_API_KEY` | unset | A Firm plan API key (`pl_...`), sent as `Authorization: Bearer`. Without it the free tier applies |
| `PROOFREAD_API` | `https://proofread.law` | Base URL, for a self-hosted or test instance |

## Free tier

Without a key, per IP address and per month:

| Tools | Quota |
|---|---|
| `check_citations`, `check_document` | 20 checks, of which 3 may be deep checks |
| `resolve_citation`, `resolve_citations` | 1,000 resolves (each citation in a list counts as one) |
| `coverage`, `render_report` | free, not counted |

There is also a limit of 20 requests an hour per IP. When a limit is reached the tool returns a plain message with the retry time or the upgrade link; nothing is thrown at the protocol level.

`.docx` upload and unlimited checks need a paid plan. See [proofread.law/pricing](https://proofread.law/pricing).

## Privacy

- The text or file goes to proofread.law, which runs on its own machine, not a cloud provider's API. It is processed in memory and discarded when the report is returned. Only counts (citations, tiers, timing) are logged, never text.
- A citation string the local register cannot resolve may be looked up in the CourtListener citation API. Only the citation string leaves, never a party name or prose.
- Deep check (`deep: true`) is opt-in. In that mode the clause before each citation (up to 700 characters) is sent to a model judge, together with the cited opinion. That is the only mode in which any of the document's prose leaves proofread.law.
- This server stores nothing on disk. It keeps the last 50 reports in memory so `render_report` can be called with a short id; they are gone when the process exits.

## The coverage caveat

Every result starts with the coverage statement, for example:

> Checked against 10.1 M cases (CourtListener bulk data 2026-06-30, last refreshed 2026-09-19); federal appellate 2019 to 2023 is 10 to 15% incomplete; Westlaw/Lexis identifiers are not resolvable; statutes, regulations and secondary sources are not checked.

Read it. A citation that is not in the register is a register fact with a coverage qualifier, not proof that the case does not exist. A red row says "check this"; the tools say what was checked and what was found, never that a case is invented.

## Example

Input:

> Title VII forbids discrimination because of sexual orientation. Bostock v. Clayton County, 509 U.S. 644 (2020).

`check_citations` returns (real output, review instance, 2026-09-20):

```
Coverage: Checked against 10.1 M cases (CourtListener bulk data 2026-06-30, last refreshed 2026-09-19); federal appellate 2019 to 2023 is 10 to 15% incomplete; Westlaw/Lexis identifiers are not resolvable; statutes, regulations and secondary sources are not checked.
Summary: 1 citation, 1 row. Check this (red): 1. Cannot verify (orange): 0. Found (green): 0.
Flagged rows:
- CHECK THIS: 509 U.S. 644 (Bostock v. Clayton County). Register has Bostock v. Clayton County at 590 U.S. 644. Check the volume. In the register, 509 U.S. 644 is Shaw v. Reno. The case named in the document exists; this citation does not point to it. Register: https://www.courtlistener.com/opinion/4760997/bostock-v-clayton-county/
Found: 0 rows resolved to a case in the register.
Report id: r_1ff74051 (give it to render_report for a markdown report). Elapsed: 0.03 s.
Storage: Nothing you submit is stored. The document is processed in memory and discarded when this report is returned; only counts (citations, tiers, timing) are logged, never text.
```

## Development

```bash
npm install
npm run build          # tsc -> dist/
npm test               # vitest, mocked fetch, no network
LIVE=1 npm test -- test/live.test.ts   # three live calls against proofread.law (counts against the free tier)
node scripts/smoke-stdio.mjs           # spawn the stdio server, initialize, tools/list, four live tool calls
node scripts/smoke-stdio.mjs --offline # the same without network
```

Layout: `src/client.ts` is the typed HTTP client (`/verify`, `/render`, `/api/coverage`, `/v1/resolve` single and batch), `src/format.ts` the compact formatter for checks, `src/resolve_format.ts` the one for register answers, `src/tools/<name>.ts` one file per tool, `src/server.ts` registers them, `src/cli.ts` picks the transport. The remaining register routes (`/v1/extract`, `/v1/case/{id}`, `/v1/coverage` per reporter) slot in the same way: one method on the client, one file under `src/tools/`.

## Publishing

See [RELEASE.md](RELEASE.md). The package is not on npm yet and the repository is private until the owner makes it public.

## License

MIT, Data Alchemy Labs.