ScriptGrain MCP server

ScriptGrain MCP server

ScriptGrain makes ChatGPT, Claude and the rest better at being you. This repository is the public setup guide for its remote MCP server: connect it to Claude, ChatGPT, Cursor or any MCP client, and your assistant can build a voice profile from your own writing, draft in that voice, and score any text against it.

• Endpoint: https://mcp.scriptgrain.com/mcp (streamable HTTP, answered as plain JSON; legacy SSE at https://mcp.scriptgrain.com/sse)
• Auth: OAuth 2.0 (sign in with your ScriptGrain account on the consent page; used by claude.ai and ChatGPT connectors), or a ScriptGrain API key sent as Authorization: Bearer sglive...
• Plans: every plan, including Free. Drafting uses credits from your plan; scoring and reading are free.
• Server version: 1.17.0, 35 tools and 2 prompts
• Website: https://scriptgrain.com · Docs: https://scriptgrain.com/docs/mcp.md · REST API: https://scriptgrain.com/docs/api.md

This repository is a guide: documentation and client configuration only. It contains no ScriptGrain source code; the application and the MCP server are private and hosted by ScriptGrain, so there is nothing to install or run.

What ScriptGrain measures

A voice profile is built from writing you have already done: 45 attributes in eight groups (lexical, syntax, tone and register, rhetoric, punctuation and format, function words, content patterns, quirks and cadence). Every draft is scored from 0 to 1 against the profile: on-voice drafts typically score 0.85 to 0.95, partial matches 0.5 to 0.8, and clearly off-voice text below 0.45. Each attribute has its own page at https://scriptgrain.com/attributes.

Connect

You need a ScriptGrain account (free): https://scriptgrain.com/auth?tab=signup&source=github_mcp

claude.ai (web) and Claude Desktop

1. Settings, then Connectors, then Add custom connector.
2. Paste https://mcp.scriptgrain.com/mcp.
3. Sign in with your ScriptGrain email and password on the consent page. If you signed up with Google, open "Paste an API key instead" and paste a key from https://scriptgrain.com/settings?tab=api.

The connector mints its own API key, named after the client, in your ScriptGrain account. Revoke it in Settings, API, and the access ends.

Claude Code

With OAuth (Claude Code opens the sign-in when you run /mcp):

claude mcp add --transport http scriptgrain https://mcp.scriptgrain.com/mcp

With an API key:

claude mcp add scriptgrain https://mcp.scriptgrain.com/mcp \
  --transport http --header "Authorization: Bearer sg_live_<your-secret>"

Project-scoped config for a shared repository: config/claude-code.mcp.json (OAuth, so no key is committed).

ChatGPT

Where your ChatGPT plan offers connectors: Settings, then Connectors, then Add custom connector, with the URL https://mcp.scriptgrain.com/mcp, and sign in with your ScriptGrain account when the consent page opens. Where connectors are not available on your plan, the free prompt builder at https://scriptgrain.com/works-with/chatgpt writes a one-page system prompt from your writing for Custom instructions instead.

Cursor (and other editors with MCP settings)

Add a remote MCP server named scriptgrain with the URL https://mcp.scriptgrain.com/mcp and complete the sign-in when the consent page opens: config/cursor.mcp.json. Where a client cannot do OAuth, send the key as a header instead: config/cursor.mcp.with-key.json. Keep a file that holds a key out of version control.

Any other MCP client

Use https://mcp.scriptgrain.com/mcp with OAuth or the Authorization: Bearer header. Every POST is answered as plain JSON, never as an event stream, so clients and proxies that only handle request and response work too. Send the Mcp-Session-Id header from the initialize response on every later call.

Tools

Shortened. The full README is on GitHub.