Prompting Claude #

Claude is well-suited to Hypersnap integrations because the API surface is small, the auth model is well-documented, and the long-form nature of these docs fits Claude's context window comfortably (llms-full.txt is a few thousand lines).

System prompt to start from #

You are helping me build an integration against the Hypersnap Farcaster API.

Complete Hypersnap API documentation is provided below in plain text.

Rules:
1. Only use endpoints, headers, fields, and behaviors that are explicitly
   described in the documentation. Do not invent endpoints or fields.
2. When the documentation says a field is required, treat it as required.
   When it says optional, you may omit it. When it gives a default, don't
   re-specify it unless I ask.
3. If the documentation contradicts your prior training about other
   Farcaster-compatible APIs, the documentation wins.
4. For signed management requests, always:
   - Include all five X-Hypersnap-* headers.
   - Hash the literal request body bytes (do not re-serialize JSON).
   - Use a fresh nonce per request.
   - Cross-check the op string against the HTTP method+path.
5. For webhook receivers, always:
   - Verify the HMAC-SHA512 signature using the raw request body bytes
     before JSON-parsing.
   - Use constant-time comparison.
   - Accept multiple valid secrets during rotation grace windows.
   - Dedupe on the event's natural key.
   - Return 2xx only after durably enqueuing the event.
6. Write idiomatic code for the target language/framework. Prefer standard
   library where possible. Avoid heavy wrapper SDKs unless I ask.

When writing code, flag any assumption that isn't explicit in the docs.

How to provide the docs #

Option A — paste llms-full.txt into the conversation #

Copy the full file. The context window in Claude Sonnet/Opus 4.x is large enough to hold it alongside your question and Claude's response. This is the most reliable option — zero tool-use, everything Claude needs is in-band.

Option B — Claude with web access #

Provide the URL of llms.txt and let Claude fetch pages via its web/file tools:

The Hypersnap docs index is at https://hypersnap-docs.qstorage.quilibrium.com/llms.txt — fetch the pages you need.

Works well in Claude Code (where Claude already has fetch tools). Less reliable in plain Claude.ai unless the docs are on a host Claude can read.

Option C — Claude Code with the repo checked out #

Most efficient for ongoing work. Check the docs repo out alongside the hypersnap repo:

/code
├── hypersnap/
└── hypersnap-docs-web/
    └── src/

Then invoke Claude Code from /code/hypersnap-docs-web/ or /code/hypersnap/ and say:

Read the markdown in ../hypersnap-docs-web/src/ first, then help me write an integration that does X.

Claude Code will open the relevant files on demand. The directory layout is semantic (concepts/, reference/webhooks/, etc.) so "read reference/webhooks and reference/miniapps" is a perfectly clear instruction.

Example prompts #

Build an agent that watches for mentions #

Using only the Hypersnap docs, write a Node.js service that:

1. Registers a webhook subscribed to cast_created events mentioning FID 12345.
2. Verifies deliveries via HMAC-SHA512.
3. For each matching cast, posts a summary to Slack via an incoming webhook.

Use ethers v6 for EIP-712 signing. Include a rotation-safe secret set.

Build a mini-app send backend #

I have a registered mini app with app_id=3Hq9ZgK2p4vNfWxR. Using only the Hypersnap docs, write a Python Flask endpoint that accepts POST /internal/notify with JSON { fid, title, body } and forwards it to the Hypersnap send endpoint. Use the spec's recommended dedupe UUID per notification.

Build a read client #

Using only the Hypersnap docs, write a TypeScript function getThread(hash: string) that returns the cast plus the first three levels of replies. Use fetch, no SDK. Handle 404.

Tips #

• Name the op string explicitly in your prompt. Claude's training data includes other Farcaster-compatible APIs where op strings look different. Spelling it out ("use webhook.create") avoids a small but real hallucination risk.
• Constrain to "only use fields in the docs". This pre-empts field inventions.
• Ask for a test in the same prompt. Claude is happy to write a unit test for signature verification alongside the main code; you want that test.
• Review the signed bytes. For EIP-712 code specifically, have Claude print the body bytes it hashed and verify they match what actually gets sent over the wire. Body hash mismatches are the #1 failure mode on first run.