Two plans. One engine. A key in your inbox.
Proseify's book engine as a hosted MCP server, priced by requests per minute. Flat monthly billing — no per-request charge — and the same engine that writes the published books. Every plan is access only: your own model key does the prose and we host no book for you — no plan includes hosted books.
Proseify MCP
- Hosted books: none — bring your own model key, the writing is yours
- The hosted MCP server at
mcp.proseify.xyz/mcp - API key or OAuth 2.1 sign-in — both accepted
- The corpus, the craft recipes and the plan → draft → evaluate pipeline
- One key, one customer, minted the moment you pay
For a first real project: the API and the pipeline, your own model key, no hosted books.
Free tier: 5,000 requests a month at 30 a minute — no key and no card, just sign in, no hosted books. Paid plans are billed monthly by our payment provider and bound to the account you sign in with.
The engine the books are made with — not a lookalike.
These plans buy access to the server behind every Proseify book: the same tools, the same corpus, the same evaluator.
https://mcp.proseify.xyz/mcp — Streamable
HTTP, reachable by any MCP client, seventeen tools including plan, draft and evaluate.Authorization: Bearer <key>,
or OAuth 2.1 access tokens from Proseify's own authorization server.What actually happens, in order.
checkout → order.paid
Checkout runs on Polar. A completed order fires a signed webhook at
api.proseify.xyz/api/polar/webhook; nothing else issues a key.
the key is minted
The worker looks your product id up in its plan table and mints one key for your email. An unrecognised product id issues nothing — the path fails closed.
the key is emailed to you
It arrives at the address on the order, together with the client config below, and it is on your account page whenever you need it again. One key per customer: a renewal, a retried delivery or a duplicate webhook reuses it instead of minting another.
you call the server
Send it as Authorization: Bearer <key> to
https://mcp.proseify.xyz/mcp. Your plan's per-minute ceiling applies; past it
the request is answered with 429 and the limit in the message.
One paste, then a request.
This is the client configuration the site itself hands out — the same block your key email contains. Paste it into your MCP client and swap in your own key.
{
"mcpServers": {
"proseify": {
"type": "http",
"url": "https://mcp.proseify.xyz/mcp",
"headers": { "Authorization": "Bearer sk-sub-YOUR-KEY" }
}
}
}Using a hosted client that cannot hold a static key — ChatGPT, Claude,
Cursor, VS Code? Point it at https://mcp.proseify.xyz/mcp and skip the key:
an unauthenticated call answers 401 with a pointer to
/.well-known/oauth-protected-resource, which names the authorization server, and
the client completes the OAuth 2.1 sign-in itself.
The developer FAQ.
What are the rate limits?
Per minute: 120 requests, enforced per credential by the MCP server. Past the ceiling a request is answered with 429 and the limit is named in the message. The free tier is capped separately at 5,000 requests a month at 30 a minute. Every plan is API access only: the writing runs on your own model key and no plan includes hosted books.
What happens if my key leaks?
It can burn your rate limit for the rest of the minute and nothing more: a plan is a flat monthly price, so a leaked key cannot spend money, and one key belongs to one customer. Nobody else can read it — the key lookup endpoint only answers a session signed in as the account that owns the address. If a key does leak, email support@proseify.xyz and we revoke it; a cancelled or refunded subscription has its key revoked automatically.
Are the books and the plans the same product?
No. The plans on this page are the developer product: a monthly subscription to the MCP server, for people building their own thing. The books are a separate product sold one payment at a time — a Short book at $19 and a Full novella at $29, written for you and delivered as PDF and EPUB. Every plan is access only — you bring your own model key and no hosted book is included. Ordering a book does not give you API access. Book pricing is here.
What does one request cost?
Nothing above the monthly price. It is flat — $9.99 a month — with no per-request charge. The per-minute number is a rate limit, not a meter: a request costs the same whether you send one or ten thousand.
Do I need an API key, or can I sign in?
Either works. The server accepts API keys sent as Authorization: Bearer <key> and OAuth 2.1 access tokens issued by Proseify's own authorization server. Hosted clients that cannot hold a static key — ChatGPT, Claude, Cursor, VS Code — use OAuth: an unauthenticated call returns 401 naming the protected-resource metadata, and the client runs the sign-in itself.
This page is the developer product. The books are separate — one payment each.
Everything above buys the engine: a monthly developer subscription to the MCP server, for people building their own thing. A book is an end product — Short book $19, Full novella $29, one payment each, written for you and delivered as PDF and EPUB. Every plan is access only — you bring your own model key and no hosted book is included. Ordering a book does not give you API access. Read the first two chapters free in the library before you decide either way.
- Building:
- MCP plan — $9.99/mo; your own model key, no hosted books
- Reading:
- Books — $19 or $29, once
- Billing:
- Monthly · one payment
- Sold as:
- Two separate products