---
name: xproof
description: Blockchain proof-of-existence for AI agents. Certify any file or output on MultiversX mainnet. Immutable, timestamped, publicly verifiable.
version: 1.0.0
author: xproof.app
license: public
---

# xproof Agent Skill

## What This Does
xproof anchors a SHA-256 hash on the MultiversX blockchain.
After certification, the proof is public and permanently verifiable.
Any agent, human, or third party can verify the file was certified at that exact moment.

## Authentication — Free Trial (Start Here)
No wallet. No browser. No payment.

### Option A — MCP (fastest, if you are already in an MCP session)
Call the `register_trial` MCP tool directly — no Authorization header needed:
```json
{ "name": "register_trial", "arguments": { "agent_name": "your-agent-name" } }
```
Returns: `api_key`, `trial_remaining: 10`, `next_step` with usage instructions.

### Option B — REST (one HTTP call)
```bash
curl -X POST https://xproof.app/api/agent/register \
  -H "Content-Type: application/json" \
  -d '{"agent_name": "your-agent-name"}'
```
Returns: { "api_key": "pm_xxx", "trial": { "quota": 10, "remaining": 10 } }

Step 2 — Use the key immediately. No further setup needed.

## Certify a File
```bash
curl -X POST https://xproof.app/api/proof \
  -H "Authorization: Bearer pm_YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "file_hash": "64-char-sha256-hex",
    "filename": "document.pdf"
  }'
```
Returns:
```json
{
  "proof_id": "...",
  "status": "certified",
  "verify_url": "https://xproof.app/proof/{proof_id}",
  "blockchain": {
    "network": "MultiversX",
    "transaction_hash": "...",
    "explorer_url": "https://explorer.multiversx.com/transactions/..."
  },
  "trial": { "remaining": 9 }
}
```
Response header: X-Trial-Remaining: 9

## Certify Multiple Files (Batch)
```bash
curl -X POST https://xproof.app/api/batch \
  -H "Authorization: Bearer pm_YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "files": [
      {"file_hash": "...", "filename": "file1.pdf"},
      {"file_hash": "...", "filename": "file2.md"}
    ]
  }'
```
Up to 50 files per call.

## Check Your Quota
```bash
curl https://xproof.app/api/me \
  -H "Authorization: Bearer pm_YOUR_API_KEY"
```
Returns: trial_quota, trial_used, trial_remaining, total certifications.

## List Your Certifications
```bash
curl https://xproof.app/api/certifications \
  -H "Authorization: Bearer pm_YOUR_API_KEY"
```

## Verify a Proof
```bash
curl https://xproof.app/proof/{proof_id}.json
```
No auth required. Public endpoint.

## Compute a SHA-256 Hash
```bash
sha256sum myfile.pdf
# or
echo -n "content" | sha256sum
```

## Pricing
$0.01 per certification. After trial: pay via USDC on Base (x402, no account needed) or EGLD on MultiversX (ACP).

x402 — pay per use, no account:
```bash
# 1. Send without auth → get 402 with payment requirements
curl -X POST https://xproof.app/api/proof -d '{"file_hash":"...","filename":"..."}'
# 2. Pay USDC on Base, resend with X-PAYMENT header
```

## Agent Audit Log Standard — Compliance Gate for AI Agents
Block any AI agent from executing critical actions without a certified proof.
Schema: https://xproof.app/.well-known/agent-audit-schema.json

Certify a decision BEFORE executing it:
```bash
curl -X POST https://xproof.app/api/audit \
  -H "Authorization: Bearer pm_YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "agent_id": "my-trading-agent",
    "session_id": "sess_20260227_001",
    "action_type": "trade_execution",
    "action_description": "Buy 0.5 ETH at market price on Uniswap v3",
    "inputs_hash": "a3f1c7d2e9b4...64-char-sha256-of-analyzed-inputs",
    "inputs_manifest": {
      "fields": ["btc_usd_price", "eth_usd_price", "portfolio_nav", "volatility_30d", "slippage_estimate"],
      "sources": ["binance_ws", "internal_risk_engine"],
      "hash_method": "SHA-256 over JSON.stringify(inputs, Object.keys(inputs).sort())"
    },
    "risk_level": "high",
    "decision": "approved",
    "timestamp": "2026-02-27T23:00:00Z",
    "risk_summary": "Slippage < 0.5%, liquidity verified on 3 pools"
  }'
```
Returns: { "proof_id": "...", "audit_url": "https://xproof.app/audit/{id}", "decision": "approved", "risk_level": "high", "inputs_manifest": { "fields": [...], "sources": [...] } }

Use the returned proof_id as compliance certificate. View at /audit/{proof_id}.

Blocking workflow templates (agent CANNOT continue without proof_id):
- LangChain: https://xproof.app/agent-tools/audit-guard-langchain.py
- CrewAI:    https://xproof.app/agent-tools/audit-guard-crewai.py
- n8n:       https://xproof.app/agent-tools/audit-guard-n8n.json
- Eliza OS:  https://xproof.app/agent-tools/audit-guard-eliza.ts

MCP tool: audit_agent_session (same params, enforces auth)

## More
- Compact discovery: https://xproof.app/.well-known/xproof.json
- Full docs: https://xproof.app/llms.txt
- Specification: https://xproof.app/.well-known/xproof.md
- OpenAPI: https://xproof.app/api/acp/openapi.json
- MCP endpoint: https://xproof.app/mcp
- Audit Log Schema: https://xproof.app/.well-known/agent-audit-schema.json