For AI agents¶

The docs are built so that an AI assistant — Claude, ChatGPT, Cursor, Codex — can read them in full and write the integration without guessing. There are three ways.

1. Markdown version of any page¶

Append .md to a page address to get its source Markdown with code samples:

HTML	Markdown
`/en/quickstart/`	`/en/quickstart.md`
`/signing/` (Russian)	`/signing.md`
`/en/`	`/en/index.md`

Every page header has a Copy as Markdown button and an "Open in ChatGPT / Claude" menu that opens the assistant with a link to the page.

2. llms.txt¶

/llms.txt — every page in both languages with a one-line description, per the llms.txt standard.
/llms-full.txt — all the docs in one file, handy to paste into context.

3. Docs MCP server¶

The MCP server gives the assistant search and read tools over the docs. Read-only, no authentication.

Tool	What it does
`search_docs(query, lang)`	Full-text search, returns sections with excerpts
`get_page(path, lang)`	A whole page in Markdown
`list_pages(lang)`	All pages with descriptions
`get_api_operation(operation_id)`	An API method from the OpenAPI spec: `createPayment`, `getPayment`, `getProject`
`get_code_example(language, topic)`	A tested sample: `curl`, `php`, `python`, `node`, `go` × `sign_request`, `verify_callback`, `create_sbp_payment`, `generate_key`, `callback_receiver`

Pages are also MCP resources: docs://ru/quickstart, docs://en/signing.

Server address: /mcp, on the same host as these docs (Streamable HTTP transport).

Claude CodeCursorCodexChatGPT

claude mcp add --transport http payment-api-docs /mcp

.cursor/mcp.json in the project or ~/.cursor/mcp.json:

{
  "mcpServers": {
    "payment-api-docs": { "url": "/mcp" }
  }
}

~/.codex/config.toml:

[mcp_servers.payment-api-docs]
url = "/mcp"

In ChatGPT: Settings → Apps & Connectors → Advanced → Developer mode, then Create, enter the server URL and choose No authentication. ChatGPT connects only to a public https:// address: for a local copy of the docs, use a tunnel.

Prompt for your assistant¶

Paste at the start of a conversation:

You are helping integrate the payments API. The source of truth is the docs:
/mcp (MCP) or llms.txt. Rules:
- Every POST is signed per RFC 9421 with Ed25519: use the ready-made function from
  get_code_example(<language>, "sign_request"); do not write signing from scratch.
- Check the function against the test vector on the signing page.
- merchant_payment_id is the idempotency key: on retry keep the id, re-sign the request.
- Verify callbacks with HMAC-SHA256 over the raw body: get_code_example(<language>, "verify_callback").
- Keep the API base URL {{base_url}} (sandbox and production differ) in configuration, not in code.