What Is an MCP Execution Receipt
MCP execution receipt definition
An MCP execution receipt is a public record for a tool call that returned a receipt. It identifies the tool name, arguments, observed result, timestamp, and receipt ID.
To verify a call, open its public receipt using the receipt ID, compare the recorded tool name, arguments, result, and timestamp with the claim, and follow the receipt's verification link. Check outside effects against the system that owns them.
A receipt records what the Zambo execution layer observed. It does not by itself establish that an unobserved external action succeeded.
MCP is the connection protocol between an AI client and a tool server. The receipt is the public record of the call that crossed that boundary. It lets a reviewer inspect the server, tool, arguments, observed result, and integrity fingerprint without relying on a chat summary.
Live receipt examples
live_price receiptOpen the public record and inspect its verification path. capability_search receiptOpen a second public record from the hosted MCP reference implementation.What an MCP receipt records
The server and named capability identify which MCP boundary ran.
The recorded arguments show what the client asked the tool to do.
The receipt reports what the implementation returned, without claiming more than it observed.
SHA-256 over the observed result gives reviewers a reproducible integrity check.
How to verify an MCP tool call
- Open the public receipt URL and confirm the receipt ID.
- Check the server name, tool name, and arguments.
- Read the observed result and its status.
- Recompute the SHA-256 fingerprint over the stated representation.
- Report only what the receipt and its evidence support.
MCP JSON-RPC lifecycle and receipt fields
Send a JSON-RPC 2.0 request to the hosted MCP endpoint https://zambo.dev/mcp. A tool invocation uses method: "tools/call" and params containing the requested name and arguments; the request's id correlates the JSON-RPC response with that request. The response uses the same JSON-RPC request ID and carries either a successful result or an error.
When the execution produces a receipt, its public record maps the call to the tool name, arguments, observed result, timestamp, and receipt ID. The JSON-RPC request ID and receipt ID are separate identifiers; do not treat them as interchangeable. The receipt is a Zambo implementation record, not an additional JSON-RPC protocol field.
- Call the tool through https://zambo.dev/mcp using the JSON-RPC request shape above.
- Read the response result or error; do not infer successful execution from a request alone.
- If a receipt ID is available, open its public receipt page and compare the recorded tool, arguments, result, and timestamp.
- Use the receipt's verification path to check the record, then separately verify any claimed outside effect with its upstream system.
Related definitions
Read the broader AI agent execution receipt definition, the AI agent audit trail definition, and the verifiable AI tool calls guide.
The hosted reference connection is documented here. Connect one server at https://zambo.dev/mcp.