# get_ots_proof

Return the .ots proof (base64) for a given OpenTimestamps anchor on an envelope. Use the official ots-cli to verify offline against Bitcoin block headers. Each seal has two anchors: kind: "byterange" commits to the signed document, kind: "signed_attrs" commits to SHA-256 of the CMS SignedAttributes (which carry the post-quantum key commitment).

Agent View of the PolicyLayer registry record for `get_ots_proof`. HTML page: https://policylayer.com/tools/com-free-sign-signing/get-ots-proof

## Facts

- Tool: `get_ots_proof`
- Server: FreeSign — Free e-signature (`https://free-sign.com/mcp`) — https://policylayer.com/tools/com-free-sign-signing.md
- Homepage: https://github.com/https://free-sign.com/mcp
- Risk category: Read (Low risk)
- Registry record: grade C, identity unverified
- Server auth posture: open
- Server CORS policy: *
- Server rate-limited: no
- Parameters: 2 (2 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `anchor_id` | string | yes |  |
| `envelope_id` | string | yes |  |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "get_ots_proof",
    "arguments": {
      "anchor_id": "<anchor_id>",
      "envelope_id": "<envelope_id>"
    }
  }
}
```

## Why get_ots_proof is rated Low

Even though get_ots_proof only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.

## Use case

AI agents call get_ots_proof to retrieve information from FreeSign — Free e-signature without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches FreeSign — Free e-signature:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "get_ots_proof": {}
  }
}
```

## Other tools on FreeSign — Free e-signature (4)

- `get_receipt` — Read — https://policylayer.com/tools/com-free-sign-signing/get-receipt.md
- `verify_audit_chain` — Read — https://policylayer.com/tools/com-free-sign-signing/verify-audit-chain.md
- `verify_document_hash` — Read — https://policylayer.com/tools/com-free-sign-signing/verify-document-hash.md
- `create_signing_envelope` — Write — https://policylayer.com/tools/com-free-sign-signing/create-signing-envelope.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=com-free-sign-signing · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/com-free-sign-signing