ScriptGrain

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)
• No account yet? https://mcp.scriptgrain.com/try needs no key or sign-in: start_session gives your assistant a 7-day guest session that builds one voice profile and scores text against it, then hands you a link to keep it in a free account
• 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 sg_live_...
• Plans: every plan, including Free. Drafting uses credits from your plan; scoring and reading are free.
• Server version: 1.23.1, 41 tools and 2 prompts; every tool has a title and read-only / destructive hints
• Building a profile: your assistant can use writing of yours it already holds (messages you typed to it, documents or emails you shared, your posts), quoted exactly, never its notes about you or AI-written text, and it shows you which pieces it sends
• 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

41 tools, listed from the server's own registrations (server 1.23.1). The tools that delete or overwrite (delete_memory, forget_piece, edit_memory, remove_monitor_url, set_voice_brain, delete_brief_template) are marked destructive, so your client can ask before running them. Credits are from your ScriptGrain plan; "free" means no credit is used.

Drafts, polish and humanise are priced by length: up to 5,000 words 1 credit, up to 10,000 words 2, up to 15,000 words 3 (the most one piece can be). A draft over 4,000 words, or a polish or humanise over 3,000 words, runs in the background: the tool returns at once with a job, and get_job shows its progress until it has succeeded (about a minute per 2,000 words). Credits are charged as the words are delivered, never above the tier asked for.

Voice profiles

Drafting, scoring and revising

Voice Brain: the memory of what you have already written

Voice monitor: published pages, scored monthly

Company context

Account

Prompts

• write_in_my_voice: draft a piece, report its score, iterate, and save the final edit.
• build_my_voice_profile: gather your own writing, create the profile, and walk through the result.

Worked examples

1. Build a voice profile from your writing and read it
2. Draft in your voice, score it, polish it, save your edit
3. Check whether pages sound like one writer, with no profile

Limits worth knowing

• 60 requests per minute per key.
• Five profile extractions an hour.
• Drafts are written in UK or US English.
• mimic_brand needs your explicit consent to analyse a website's writing.
• Payments never happen through the connector.

Privacy and security

• With OAuth, your password is used once on the consent page and never stored; the grant holds an encrypted key that is never shown to the client, and revoking it in Settings, API ends the access.
• With a pasted key, keep the key in the client's secret store or an untracked config file.
• ScriptGrain receives only what a tool call contains.
• Subprocessors and data handling: https://scriptgrain.com/trust · Privacy: https://scriptgrain.com/privacy · Terms: https://scriptgrain.com/terms
• Report a security issue to [email protected] (https://scriptgrain.com/.well-known/security.txt).

More about ScriptGrain

• The 45 attributes, one page each: https://scriptgrain.com/attributes
• How a voice is measured and scored: https://scriptgrain.com/reference/voice-measurement-framework
• Published studies, with method and limitations: https://scriptgrain.com/research
• Every MCP tool and what it costs: https://scriptgrain.com/reference/mcp-tool-reference
• For AI assistants: https://scriptgrain.com/llms.txt

Support

[email protected] · https://scriptgrain.com/support

ScriptGrain is a product of Adapt Progress Evolve Limited, registered in England and Wales (10047328), London.

Licence

The documentation and configuration files in this repository are released under the MIT licence (see LICENSE). The ScriptGrain name, logo and service are not covered by it.