@proofslip/mcp-server

MCP server for ProofSlip — receipt-based verification for AI agent workflows. Create, verify, and poll ephemeral receipts that let agents prove what happened before deciding what happens next.

Tools

create_receipt

Create a receipt to record that something happened. Receipts expire after 24 hours by default.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | type | enum | Yes | action, approval, handshake, resume, failure | | status | string | Yes | Freeform status (e.g. "success", "pending", "failed") | | summary | string | Yes | What happened — max 280 chars | | payload | object | No | Structured JSON data (max 4KB) | | ref | object | No | Workflow references (run_id, agent_id, workflow_id, etc.) | | expires_in | number | No | TTL in seconds (60–86400, default 24h) | | idempotency_key | string | No | Prevents duplicate receipts on retry | | audience | "human" | No | Enrich verify page with social cards |

Requires: PROOFSLIP_API_KEY environment variable.

verify_receipt

Verify a receipt and retrieve its full data before deciding what to do next.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | receipt_id | string | Yes | The receipt ID (starts with rct_) |

No API key required.

check_receipt_status

Lightweight status poll — returns only status and polling guidance, no payload.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | receipt_id | string | Yes | The receipt ID (starts with rct_) |

No API key required. Use this instead of verify_receipt when you only need to know if state has changed.

signup

Get a free API key (500 receipts/month).

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | email | string | Yes | Your email address |

No API key required.

Usage Example

You: "Create a receipt proving we sent the welcome email"

Agent calls create_receipt:
  type: "action"
  status: "success"
  summary: "Sent welcome email to [email protected]"
  ref: { workflow_id: "onboarding-123", agent_id: "email-agent" }

→ Returns receipt_id, verify_url, is_terminal: true

You: "Verify receipt rct_abc123 before sending the follow-up"

Agent calls verify_receipt:
  receipt_id: "rct_abc123"

→ Returns full receipt: type, status, summary, payload, ref
→ Agent confirms the action happened before proceeding

You: "Check if the approval is still pending"

Agent calls check_receipt_status:
  receipt_id: "rct_def456"

→ Returns: status: "pending", is_terminal: false, next_poll_after_seconds: 30
→ Agent waits 30s then checks again

Setup

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "proofslip": {
      "command": "npx",
      "args": ["-y", "@proofslip/mcp-server"],
      "env": {
        "PROOFSLIP_API_KEY": "ak_your_key_here"
      }
    }
  }
}

Cursor / Windsurf

Add to MCP settings:

{
  "mcpServers": {
    "proofslip": {
      "command": "npx",
      "args": ["-y", "@proofslip/mcp-server"],
      "env": {
        "PROOFSLIP_API_KEY": "ak_your_key_here"
      }
    }
  }
}

Claude Code

claude mcp add proofslip -- npx -y @proofslip/mcp-server

Then set your API key in your environment or .env file.

Configuration

| Variable | Required | Description | |----------|----------|-------------| | PROOFSLIP_API_KEY | For creating receipts | Your API key (starts with ak_) | | PROOFSLIP_BASE_URL | No | API base URL (default: https://proofslip.ai) |

Get an API Key

Use the signup tool from any MCP client, or:

curl -X POST https://proofslip.ai/v1/auth/signup \
  -H "Content-Type: application/json" \
  -d '{"email": "[email protected]", "source": "api"}'

Links

• Live Site
• API Docs
• Example Receipt
• Context Capsule (sister product — execution context for handoffs)
• GitHub

License

MIT