How to Send a Signing Packet from an Agent Without Webhooks

The Webhook Tax on AI Agents

Most traditional e-signature platforms were built around asynchronous webhooks. In that model, your application must host an internet-accessible HTTP endpoint, verify cryptographic payload signatures, handle connection drops, and manage retry backoffs.

For autonomous AI agents running inside developer IDEs (like Cursor or Windsurf), local desktop runtimes (like Claude Desktop), or ephemeral task workers, this architecture breaks down immediately. An agent running on a laptop or within a sandboxed container does not have an inbound public URL to accept push webhooks.

Forcing an agent to stand up tunnel proxies or manage complex ingress listeners creates unnecessary failure points. The solution is straightforward: let the agent dispatch the signing packet directly over HTTP and check the state on demand.

The Aha Moment: Don't Stand Up Connect

When an agent needs a human counterparty to sign a non-disclosure agreement, service contract, or authorization form, the agent should not instruct the user to configure enterprise webhook relays or set up dedicated server pipelines.

Instead, the agent calls the Signbee API directly. Signbee takes care of compiling the document, emailing the parties with secure signing links, collecting verifiable signatures, and appending a cryptographic audit trail. The agent remains lightweight, stateless, and focused on its core task.

The Live API Pattern: Send and Check

The entire document workflow requires only two core endpoints: POST /api/v1/send to create and dispatch the signing packet, and GET /api/v1/documents/{id} to inspect its progress.

1. Dispatching the Signing Packet

The agent submits markdown (or a PDF URL) plus recipient_name and recipient_email. With an API key, the sender is pre-verified and is not sent in the body.

curl -X POST https://signb.ee/api/v1/send \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "markdown": "# Mutual NDA\n\nThis agreement...",
    "recipient_name": "Bob Smith",
    "recipient_email": "bob@acme.com"
  }'

Signbee returns document_id, status pending_recipient, sender, recipient, and expires_at:

{
  "document_id": "cmm...",
  "status": "pending_recipient",
  "sender": "Alice Chen",
  "recipient": "Bob Smith",
  "expires_at": "2026-04-19T12:00:00.000Z"
}

2. Checking Status On Demand

Whenever the agent resumes execution or needs to confirm completion before continuing a workflow, it queries the document endpoint:

curl https://signb.ee/api/v1/documents/cmm... \
  -H "Authorization: Bearer YOUR_API_KEY"

When both parties have signed, status is signed and signed_pdf_url is the certified PDF. The SHA-256 certificate is on that PDF, not a field on GET:

{
  "document_id": "cmm...",
  "status": "signed",
  "title": "Mutual NDA",
  "sender": { "name": "Alice Chen", "signed_at": "2026-08-30T12:04:12.000Z" },
  "recipient": { "name": "Bob Smith", "signed_at": "2026-08-30T12:04:12.000Z" },
  "original_pdf_url": "...",
  "signed_pdf_url": "https://signb.ee/...",
  "signing_url": null,
  "expires_at": "...",
  "created_at": "..."
}

MCP Tools: Native Agent Integration

If your agent connects via the Model Context Protocol (MCP) or uses standard agent skill packages, you do not need to write custom REST wrappers.

To install the MCP server or the agent skill, run:

# Install and run the MCP Server
npx -y signbee-mcp

# Or install the Agent Skill
npx skills add signbee/skill

The Signbee MCP server exposes two dedicated tools designed specifically for LLM tool-calling:

• send_document: Takes dynamic markdown agreement text, sender information, and recipient details to generate and dispatch a signing packet.
• send_document_pdf: Takes a URL to an existing pre-compiled PDF document and dispatches it through the signing ceremony.

Here is an example of adding the MCP server to your agent configuration:

{
  "mcpServers": {
    "signbee": {
      "command": "npx",
      "args": ["-y", "signbee-mcp"],
      "env": {
        "SIGNBEE_API_KEY": "your_api_key_here"
      }
    }
  }
}

Limitations to Keep in Mind

Please note: markdown tables are not supported.

Automating Verification in Agent Scripts

When building autonomous scripts in Python or TypeScript, an agent can check document status at strategic intervals without maintaining persistent open connections or listening sockets.

import httpx
import time

def wait_for_document_signature(document_id: str, api_key: str, max_retries: int = 10, delay_seconds: int = 30):
    url = f"https://signb.ee/api/v1/documents/{document_id}"
    headers = {
        "Authorization": f"Bearer {api_key}",
        "Accept": "application/json"
    }

    with httpx.Client() as client:
        for attempt in range(max_retries):
            response = client.get(url, headers=headers)
            if response.status_code == 200:
                data = response.json()
                status = data.get("status")
                if status == "signed":
                    print(f"Document {document_id} signed successfully!")
                    print(f"Certified PDF: {data.get('signed_pdf_url')}")
                    return data
                print(f"Current status: {status}. Checking again in {delay_seconds}s...")
            time.sleep(delay_seconds)

    print("Document signing window expired.")
    return None

Frequently Asked Questions

Last updated: August 30, 2026 · Michael Beckett is the founder of Signbee and B2bee Ltd.