# Send xProof — Blockchain Proof for Agents to your agent
Hand the extracted package to your coding agent with a concrete install brief instead of figuring it out manually.
## Fast path
- Download the package from Yavira.
- Extract it into a folder your agent can access.
- Paste one of the prompts below and point your agent at the extracted folder.
## Suggested prompts
### New install

```text
I downloaded a skill package from Yavira. Read SKILL.md from the extracted folder and install it by following the included instructions. Tell me what you changed and call out any manual steps you could not complete.
```
### Upgrade existing

```text
I downloaded an updated skill package from Yavira. Read SKILL.md from the extracted folder, compare it with my current installation, and upgrade it while preserving any custom configuration unless the package docs explicitly say otherwise. Summarize what changed and any follow-up checks I should run.
```
## Machine-readable fields
```json
{
  "schemaVersion": "1.0",
  "item": {
    "slug": "xproof",
    "name": "xProof — Blockchain Proof for Agents",
    "source": "tencent",
    "type": "skill",
    "category": "AI 智能",
    "sourceUrl": "https://clawhub.ai/jasonxkensei/xproof",
    "canonicalUrl": "https://clawhub.ai/jasonxkensei/xproof",
    "targetPlatform": "OpenClaw"
  },
  "install": {
    "downloadUrl": "/downloads/xproof",
    "sourceDownloadUrl": "https://wry-manatee-359.convex.site/api/v1/download?slug=xproof",
    "sourcePlatform": "tencent",
    "targetPlatform": "OpenClaw",
    "packageFormat": "ZIP package",
    "primaryDoc": "SKILL.md",
    "includedAssets": [
      "SKILL.md"
    ],
    "downloadMode": "redirect",
    "sourceHealth": {
      "source": "tencent",
      "slug": "xproof",
      "status": "healthy",
      "reason": "direct_download_ok",
      "recommendedAction": "download",
      "checkedAt": "2026-05-05T07:06:04.930Z",
      "expiresAt": "2026-05-12T07:06:04.930Z",
      "httpStatus": 200,
      "finalUrl": "https://wry-manatee-359.convex.site/api/v1/download?slug=xproof",
      "contentType": "application/zip",
      "probeMethod": "head",
      "details": {
        "probeUrl": "https://wry-manatee-359.convex.site/api/v1/download?slug=xproof",
        "contentDisposition": "attachment; filename=\"xproof-1.5.0.zip\"",
        "redirectLocation": null,
        "bodySnippet": null,
        "slug": "xproof"
      },
      "scope": "item",
      "summary": "Item download looks usable.",
      "detail": "Yavira can redirect you to the upstream package for this item.",
      "primaryActionLabel": "Download for OpenClaw",
      "primaryActionHref": "/downloads/xproof"
    },
    "validation": {
      "installChecklist": [
        "Use the Yavira download entry.",
        "Review SKILL.md after the package is downloaded.",
        "Confirm the extracted package contains the expected setup assets."
      ],
      "postInstallChecks": [
        "Confirm the extracted package includes the expected docs or setup files.",
        "Validate the skill or prompts are available in your target agent workspace.",
        "Capture any manual follow-up steps the agent could not complete."
      ]
    }
  },
  "links": {
    "detailUrl": "https://openagent3.xyz/skills/xproof",
    "downloadUrl": "https://openagent3.xyz/downloads/xproof",
    "agentUrl": "https://openagent3.xyz/skills/xproof/agent",
    "manifestUrl": "https://openagent3.xyz/skills/xproof/agent.json",
    "briefUrl": "https://openagent3.xyz/skills/xproof/agent.md"
  }
}
```
## Documentation

### xProof — Blockchain Proof of Existence for Agents

xProof anchors agent outputs to the MultiversX blockchain. Any text, hash, file, or decision becomes a permanent, tamper-proof record with a verifiable on-chain certificate.

Use this skill when:

Certifying agent outputs, decisions, or reports that need to be verifiable
Anchoring content before it is shared, published, or acted upon
Building audit trails for autonomous agent pipelines
Proving a document or output existed at a specific point in time

### Authentication

Option 1 — API Key (recommended):
Set XPROOF_API_KEY in your environment. Get a key at https://xproof.app.

Option 2 — x402 (no account required):
Send USDC on Base. The API returns a 402 with payment instructions; include the X-Payment header (base64-encoded JSON) in your follow-up request.

### Certify Text or a Hash

# Certify text content
curl -s -X POST https://xproof.app/api/proof \\
  -H "Authorization: Bearer $XPROOF_API_KEY" \\
  -H "Content-Type: application/json" \\
  -d '{
    "content": "The agent decided: deploy to production at 2026-02-20T14:00:00Z",
    "metadata": {"agent": "deploy-bot", "pipeline": "release-v2.1"}
  }'

# Certify a SHA-256 hash (if you already have it)
curl -s -X POST https://xproof.app/api/proof \\
  -H "Authorization: Bearer $XPROOF_API_KEY" \\
  -H "Content-Type: application/json" \\
  -d '{"hash": "sha256:<64-char-hex>"}'

Response:

{
  "id": "cert_abc123",
  "status": "pending",
  "hash": "sha256:...",
  "txHash": "...",
  "blockchainUrl": "https://explorer.multiversx.com/transactions/...",
  "verifyUrl": "https://xproof.app/verify/cert_abc123",
  "certifiedAt": "2026-02-20T14:00:05Z"
}

### Certify a File

# Hash a file locally and certify the hash
FILE_HASH=$(sha256sum report.pdf | awk '{print $1}')

curl -s -X POST https://xproof.app/api/proof \\
  -H "Authorization: Bearer $XPROOF_API_KEY" \\
  -H "Content-Type: application/json" \\
  -d "{\\"hash\\": \\"sha256:${FILE_HASH}\\", \\"metadata\\": {\\"filename\\": \\"report.pdf\\"}}"

### Batch Certify (up to 50)

curl -s -X POST https://xproof.app/api/batch \\
  -H "Authorization: Bearer $XPROOF_API_KEY" \\
  -H "Content-Type: application/json" \\
  -d '{
    "proofs": [
      {"content": "Output 1"},
      {"content": "Output 2"},
      {"hash": "sha256:<hash-3>"}
    ]
  }'

### Verify a Certificate

# By certificate ID
curl -s https://xproof.app/api/proof/cert_abc123

# Response includes on-chain status: pending | confirmed | failed

### MX-8004 Integration (MultiversX Agent Validation Loop)

xProof implements the full MX-8004 validation loop. To submit a certified proof as an on-chain MX-8004 validation:

# Step 1: Certify the output
CERT=$(curl -s -X POST https://xproof.app/api/proof \\
  -H "Authorization: Bearer $XPROOF_API_KEY" \\
  -H "Content-Type: application/json" \\
  -d '{"content": "Agent output to validate"}')

CERT_ID=$(echo $CERT | jq -r '.id')
CERT_HASH=$(echo $CERT | jq -r '.hash')

# Step 2: Submit as MX-8004 proof (handled by xProof internally)
# xProof anchors on MultiversX and calls giveFeedback on the Validation Registry.
# The verifyUrl in the response is the permanent on-chain reference.
echo "Certificate: $CERT_ID"
echo "Verify at: $(echo $CERT | jq -r '.verifyUrl')"

### x402 Payment (No Account Required)

# Step 1: Attempt the request — receive 402
RESPONSE=$(curl -s -w "\\n%{http_code}" -X POST https://xproof.app/api/proof \\
  -H "Content-Type: application/json" \\
  -d '{"content": "Certify this"}')

HTTP_CODE=$(echo "$RESPONSE" | tail -1)
BODY=$(echo "$RESPONSE" | head -1)

if [ "$HTTP_CODE" = "402" ]; then
  # Step 2: Parse payment instructions and pay with USDC on Base
  # Then resubmit with X-Payment header (base64-encoded payment JSON)
  echo "Payment required: $(echo $BODY | jq -r '.accepts[0]')"
fi

### MCP Server

xProof exposes an MCP server at https://xproof.app/mcp.

Add to your OpenClaw config:

{
  "mcp": {
    "servers": {
      "xproof": {
        "url": "https://xproof.app/mcp",
        "headers": {"Authorization": "Bearer ${XPROOF_API_KEY}"}
      }
    }
  }
}

Available MCP tools: certify_content, certify_hash, certify_batch, verify_proof.

### Pricing

VolumePrice0 - 100K certs/month$0.05/cert100K - 1M certs/month$0.025/cert1M+ certs/month$0.01/cert

Check current pricing: curl https://xproof.app/api/pricing

### Security & Privacy

Content submitted via content field is hashed server-side before anchoring; the original text is not stored on-chain.
Only the SHA-256 hash and optional metadata are written to MultiversX.
API keys are scoped to a single account and can be rotated at https://xproof.app.
x402 payments are processed on Base; no account or email required.

External endpoints called: https://xproof.app only.

By using this skill, hashes and optional metadata are sent to xproof.app for blockchain anchoring on MultiversX.

### Resources

Homepage: https://xproof.app
API docs: https://xproof.app/llms.txt
Full reference: https://xproof.app/llms-full.txt
Agent manifest: https://xproof.app/.well-known/agent.json
MCP Registry: https://registry.modelcontextprotocol.io/v0/servers?search=xproof
MultiversX explorer: https://explorer.multiversx.com
## Trust
- Source: tencent
- Verification: Indexed source record
- Publisher: jasonxkensei
- Version: 1.2.0
## Source health
- Status: healthy
- Item download looks usable.
- Yavira can redirect you to the upstream package for this item.
- Health scope: item
- Reason: direct_download_ok
- Checked at: 2026-05-05T07:06:04.930Z
- Expires at: 2026-05-12T07:06:04.930Z
- Recommended action: Download for OpenClaw
## Links
- [Detail page](https://openagent3.xyz/skills/xproof)
- [Send to Agent page](https://openagent3.xyz/skills/xproof/agent)
- [JSON manifest](https://openagent3.xyz/skills/xproof/agent.json)
- [Markdown brief](https://openagent3.xyz/skills/xproof/agent.md)
- [Download page](https://openagent3.xyz/downloads/xproof)