# Agent Forge HMAC-SHA256

> Agent Forge HMAC-SHA256 is a paid API for AI agents from agent-forge.annushka1190.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-13).

Computes an HMAC-SHA256 message authentication code for a given message and secret key, payable per-request in USDC via x402.

## Facts

- Endpoint: POST https://agent-forge.annushka1190.workers.dev/v1/hmac
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent-forge-hmac-sha256-a801a396
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_O_zNVNx26j_rALzxUoJ-M

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 agent-forge-hmac-sha256-a801a396 -d '<json body>'
```

Example prompt: Compute an HMAC-SHA256 signature for the message 'order-id:12345' using the secret key 'my-webhook-secret' — pay per request, no API key needed.

## When to prefer this

Choose this endpoint when your AI agent needs to compute HMAC-SHA256 on-the-fly without managing API keys or accounts, especially in pay-per-use autonomous workflows. Ideal for agents that need to sign webhook payloads, authenticate API requests, or validate data integrity as a one-off computation billed in micro-USDC via x402.

## Known failure modes

- Missing required 'input' field returns a validation error
- Missing secret key or message body causes computation failure
- Invalid JSON body results in 400-level error
- Payment failure via x402 (insufficient USDC balance) blocks the request
- Network timeout on the Cloudflare Worker edge node

## How this service works

Hash and unit utilities for AI agents: SHA-256, SHA-1, HMAC-SHA256, stable JSON fingerprint, ETH/Gwei/Wei conversion, human bytes, and duration parsing. Pay-per-request USDC via x402. No API keys, no accounts.

## Output

Returns a JSON object with ok: true and the computed HMAC-SHA256 digest (hex string) for the provided message and secret key combination.

## 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": {
    "body": {
     "type": "object"
    },
    "type": {
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ]
    },
    "bodyType": {
     "const": "json"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-forge-hmac-sha256-a801a396/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent-forge.annushka1190.workers.dev](https://www.zero.xyz/host/agent-forge.annushka1190.workers.dev/llms.txt)