ScriptGrain makes Claude better at being you

By Jack Stovell · published 2026-09-20

Claude can write for you. It cannot measure you. ScriptGrain measures your voice as 45 attributes from writing you have already published, connects to Claude, and scores every draft against the measurement, so the assistant you already use writes as you rather than as its average.

Start with the prompt builder below: paste your writing and get a system prompt written in measured numbers, ready for custom instructions or a project. The connector does the same with the full profile.

How to connect

Works with Claude (claude.ai, Claude Desktop and Claude Code).

  1. Measure your voice. Create a free ScriptGrain account and paste three or more pieces you wrote (3,000 words works best). The profile takes a few minutes and costs nothing.
  2. Connect. In claude.ai open Settings, then Connectors, then Add custom connector, and give it `https://mcp.scriptgrain.com/mcp`. Claude opens ScriptGrain's consent page; sign in and the connector is live. In Claude Code run `claude mcp add scriptgrain https://mcp.scriptgrain.com/mcp` and sign in the same way.
  3. Write, then score. Claude can build the profile too: give it three or more pieces of your writing and ask it to call `create_profile`, then `get_profile` until the status is complete. From then on every draft can be generated in the voice, scored with `check_voice_match`, and polished toward 0.9.

What changes

Without a profile, Claude writes from a description: whatever you can say about your own style. Most of a voice is what you cannot say: contraction rate, clause ordering, how often you open with a question, the words you reach for without noticing. With ScriptGrain connected, Claude writes from the measured profile and every draft comes back with a voice-match score and the exact features that moved. On-voice drafts score 0.85 to 0.95; a clearly different voice scores under 0.45. Paste any two pieces into the free off-voice check to see the same measurement with no account.

What stays free

The profile, the connector, scoring any text against your profile, and comparing pieces with no profile at all are free on every plan. Generating drafts in your voice, polishing toward a target and the monthly voice monitor are paid.

Questions

Do I need a paid plan to connect ScriptGrain to Claude?

No. The connector, the profile and voice-match scoring are on the Free plan. Paid plans add generation credits, polishing and the monthly voice monitor.

Does Claude send my conversations to ScriptGrain?

No. Claude calls ScriptGrain only when it uses a tool (score this text, generate this brief), and ScriptGrain receives only what that call contains. Your API key or sign-in token never appears in the conversation.

What is the voice-match score measuring?

Stylistic alignment: sentence rhythm, punctuation habits, pronoun mix, formality, argument structure and the rest of the measured attributes, compared feature by feature against your profile. It says whether the draft sounds like you, not whether it is any good.

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