Use Thirdraft with AI agents

For Claude, Claude Code, Cursor and any agent that supports MCP.

AI agents write more and more on your behalf: emails, docs, Slack updates, PR descriptions. Connect Thirdraft and your agent can run that text through your own voice before it goes out, learned from things you've actually written. Facts, names and numbers stay exactly as they were.

You'll need a Thirdraft account with a few writing samples. Free accounts get 3 rewrites a week to try it (shared with the website and extension); Thirdraft Personal covers everyday use.

Connect

Every option signs you in to Thirdraft in your browser the first time, then you click Allow. No keys to copy.

Claude (desktop or web)

Settings → Connectors → Add custom connector. Name it Thirdraft, paste this URL, then click Connect:

https://api.thirdraft.com/mcp

Cursor or VS Code

Add to Cursor Add to VS Code

Or add it yourself, in ~/.cursor/mcp.json:

{
  "mcpServers": {
    "thirdraft": { "url": "https://api.thirdraft.com/mcp" }
  }
}

Claude Code

Run this once, then type /mcp in Claude Code and sign in:

claude mcp add --transport http thirdraft https://api.thirdraft.com/mcp

Other agents

Any MCP client that supports remote servers with OAuth can connect to https://api.thirdraft.com/mcp. If yours can't sign in, create an API key under Connect an agent at thirdraft.com/app and send it as Authorization: Bearer <key>.

Zapier, Make and n8n

Automations call Thirdraft with a web request and an API key. Create a key under Connect an agent at thirdraft.com/app, then add the step: in Zapier, Webhooks by Zapier → Custom Request; in Make, the HTTP module; in n8n, the HTTP Request node.

Method: POST. URL:

https://api.thirdraft.com/mcp

Headers:

Authorization: Bearer YOUR_API_KEY
Content-Type: application/json
Accept: application/json, text/event-stream

Body (put your earlier step's text in text):

{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"rewrite_in_my_voice","arguments":{"text":"TEXT TO REWRITE","context":"email to a client"}}}

The rewrite comes back at result → content → 1 → text (in n8n and Make, result.content[0].text). Use it in your next step, like a Gmail draft or a Slack message.

Each run uses one rewrite from your plan. Text with quotes or line breaks has to be escaped for JSON; Make and n8n do that for you if you build the body as JSON fields instead of raw text.

Make it automatic

Agents use Thirdraft when they're told to. Add this to your agent's instructions (Claude Code's CLAUDE.md, a Cursor rule, or a Claude project's instructions):

Before publishing anything you write for me (emails, docs, messages, posts, PR descriptions), run it through Thirdraft's rewrite_in_my_voice tool and use the result.

What your agent can do

Tool	What it does
`rewrite_in_my_voice`	Rewrites text so it sounds like you, keeping every fact, name and number. It can say what the text is for, like "Slack update".
`add_writing_sample`	Saves something you wrote (a past email you paste in) so Thirdraft learns your voice. Never for AI-written text.
`get_my_voice`	Reads a short summary of how you write, so the agent can draft closer to you first. Read-only.
`check_status`	Your plan and how much you have left today. Read-only.

Agents can't delete your samples or read them out. Manage samples at thirdraft.com/app.

Try it

Once connected, ask your agent something like:

Draft an email to Dana at Northwind: the launch is moving from May 12 to May 19 because our payments vendor is running late. The pilot stays at 50 seats, and we'll cover the extra week of support at no cost. Keep it short and honest, then run it through Thirdraft so it sounds like me before I send it.

New to Thirdraft? Give it your voice first:

Here are three emails I wrote. Add them to Thirdraft as writing samples: …

Limits

150 rewrites a week on Personal, 375 on Pro, shared with the website and extension (no more than 10 a minute through agents), up to 8,000 characters each.
20 samples a day through agents, up to 2,000 characters each.
Rewrites reset every Monday, samples at midnight UTC. See fair use.

Your data

Text your agent sends is handled exactly like text you rewrite yourself: sent to Anthropic to write the rewrite, and not stored. Agent rewrites are never saved as samples, so your agent's writing never teaches Thirdraft what you sound like. Samples an agent adds are marked "via agent" so you can review them. Full details in the privacy policy.

If something doesn't work

"Thirdraft doesn't know this person's voice yet": add a few things you've written, at thirdraft.com/app or through add_writing_sample.
"Used its 3 free rewrites for this week": they come back on Monday, or see pricing.
Sign-in doesn't finish: remove Thirdraft from your agent, add it again, and sign in with the same account you use on the website.
To disconnect: remove Thirdraft in your agent's settings. API keys can be revoked at thirdraft.com/app.

Anything else: support@thirdraft.com.