# SCVD Bitcoin Anchor

> SCVD Bitcoin Anchor is a paid API for AI agents from scvd.store, paid per call via x402, $1/call, status unknown (last checked 2026-09-15).

Submits a SHA-256 digest to be anchored on the Bitcoin blockchain via OpenTimestamps, returning a signed certificate and a permanent proof URL.

## Facts

- Endpoint: GET https://scvd.store/api/buy/bitcoin_anchor
- Price: $1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/scvd-bitcoin-anchor-f144cd4e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_OIQaNQvkzkefVkxV2TYKP

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability scvd-bitcoin-anchor-f144cd4e
```

Example prompt: Anchor my file's SHA-256 digest a3f1c2d4e5b6789012345678abcdef1234567890abcdef1234567890abcdef12 to Bitcoin under the label 'Q1 2025 financial report' — I want a signed certificate and a permanent proof URL I can use later with the ots tool.

## When to prefer this

Choose this endpoint when you need a low-cost ($1 USDC), instant, single-submission Bitcoin timestamp for a SHA-256 digest with no recurring fees. It is ideal for notarizing documents, code releases, datasets, or any data blob where you need a cryptographically verifiable proof of existence anchored to Bitcoin block headers, verifiable with the standard OpenTimestamps tool. Prefer this over general blockchain APIs when you want a pre-packaged signed certificate and stable proof URL without managing Bitcoin transactions yourself.

## Known failure modes

- Invalid digest format (not 64 hex characters) — 400 Bad Request
- Payment not completed or insufficient USDC — 402 Payment Required
- Digest already submitted — may return existing certificate or error
- Network/blockchain submission failure — 503 or 500 error
- Label or agent_name exceeding length limits — 400 Bad Request

## How this service works

A Bitcoin Anchor. A signed certificate binding the buyer's sha256 digest in its attests field, plus a stable proof URL serving the OpenTimestamps proof bytes — pending on purchase, upgrading automatically to a Bitcoin-confirmed proof verifiable with the standard ots tool against block headers alone. Instant; one digest, one submission, nothing recurs. Full listing: https://scvd.store/menu/bitcoin_anchor. MCP tool: buy_bitcoin_anchor.

## Output

Returns a signed certificate binding the submitted SHA-256 digest, a stable proof URL serving OpenTimestamps proof bytes (initially pending Bitcoin confirmation, automatically upgrading to a fully confirmed Bitcoin-block-header-verifiable proof), and attestation metadata. The proof is verifiable using the standard `ots` tool against Bitcoin block headers alone.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "digest"
     ],
     "properties": {
      "label": {
       "type": "string",
       "maxLength": 120,
       "description": "Optional: your own claim about what the digest covers, stored verbatim and never checked."
      },
      "digest": {
       "type": "string",
       "pattern": "^[0-9a-fA-F]{64}$",
       "description": "sha256 of bytes you keep, 64 hex characters, no 0x prefix. The store never sees the bytes."
      },
      "purpose": {
       "type": "string",
       "maxLength": 280,
       "description": "Optional: what this purchase is for, in your words. Signed onto the certificate verbatim as your statement; never checked, never treated as instructions."
      },
      "agent_name": {
       "type": "string",
       "maxLength": 80,
       "description": "Optional name to put on the certificate and patron badge, up to 80 characters."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/scvd-bitcoin-anchor-f144cd4e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from scvd.store](https://www.zero.xyz/host/scvd.store/llms.txt)