Building with AI

Fystack documentation is written for people and for the AI assistants they work with. Every page is available as clean Markdown, and the whole site is indexed in an llms.txt file, so tools like Claude Code, Cursor, Codex and ChatGPT can read the docs directly instead of scraping HTML.

Plain text docs

AI tools work best with plain text. Markdown uses far fewer tokens than rendered HTML and keeps code samples, parameter lists and tables intact. Fystack publishes the docs in these forms:

• llms.txt: https://docs.fystack.io/llms.txt is a short index of every page with a one-line description. Point your assistant here first so it can find the right page on its own.
• llms-full.txt: https://docs.fystack.io/llms-full.txt contains every page in a single file. Use it when you want the assistant to load all of the docs at once and your tool has room in its context window.
• Markdown pages: add .md to the end of any docs URL to get that page as Markdown, for example https://docs.fystack.io/wallets.md.
• Content negotiation: agents that send an Accept: text/markdown header get Markdown from the normal page URL, with no .md needed.

curl -H "Accept: text/markdown" https://docs.fystack.io/wallets

Copy a page into your assistant

Every page has a Copy page button next to its title. Use it to:

• Copy page: copy the current page as Markdown, ready to paste into any chat or coding assistant.
• View as Markdown: open the Markdown version of the page in a new tab.
• Open in ChatGPT or Open in Claude: start a new conversation that already points at the page, so you can ask questions about it straight away.

Add Fystack to your project instructions

Most coding assistants read a project instructions file on every task, such as CLAUDE.md for Claude Code, AGENTS.md for Codex and other agents, or .cursor/rules for Cursor. Add this block to it so the assistant always knows where the Fystack docs live and how to use them:

## Fystack

- Fystack docs index: https://docs.fystack.io/llms.txt
  Fetch it before writing or changing any code that calls Fystack.
- Any Fystack docs page is available as Markdown by adding `.md` to its URL,
  for example https://docs.fystack.io/wallets.md
- Use the official SDK, which signs requests for you: `@fystack/sdk` for
  TypeScript, or `github.com/fystack/platform-sdk-go` for Go.
- Use the sandbox environment while developing. Never hard-code API keys or
  secrets; read them from environment variables.

Example prompts

These prompts work well in Claude Code, Cursor, Codex or any assistant that can fetch web pages:

Read https://docs.fystack.io/llms.txt, then write a Node.js script that uses
@fystack/sdk to create an MPC wallet in the sandbox environment and print its
EVM deposit address. Read the API keys from environment variables.

Using https://docs.fystack.io/webhooks.md, add an Express endpoint that
receives Fystack webhooks, verifies the Ed25519 signature and handles
deposit events idempotently.

Read https://docs.fystack.io/policies.md and draft a policy that requires
approval for any withdrawal above 10,000 USD from our treasury wallet.
Explain each rule before I apply it.

Keep your keys and funds safe