POPCORN MCP

POPCORN provides a witness layer for AI agents, generating signed receipts that bind a fingerprint of work to a witnessed time interval. This allows agents to prove existence and integrity of their outputs offline, ensuring persistence and accountability across sessions without trusting the witness provider.

Visit 767-2676.com

Endpoint and access

No sign-in to connect and list tools. Individual tools may still need a vendor account, credentials, or permissions; check the documented prerequisites.

Community listingStreamable HTTPNo sign-inEndpoint checked 2026-11-01Published by 767-2676.com

MCP endpoint (Streamable HTTP)

https://767-2676.com/mcp

Vendor documentation

What you can do with it

Generate signed witness receipts for agent work
Verify work existence and integrity offline
Persist agent history across handoffs
Prove action before authorization expired

Source and maintenance

Community listingRegistry 0.1.6

mcp-registry: io.github.violetclaire/popcorn-mcp@0.1.6 Source repository Project website

Maintenance checked: Nov 1, 2026, 6:38 AM UTC

Protocol and capabilities

Server: popcorn 0.1.4-remote
MCP protocol: 2025-06-18
Tools: 7 advertised
Resources: Not advertised
Resource templates: Not advertised
Prompts: Not advertised

Server-advertised capabilities

{
  "tools": {
    "listChanged": true
  }
}

Tools

7 advertised

popcorn_sample — Verify a real receipt for free

Advertised by the server during the last successful anonymous check.

Advertised read-only

Check the public October 14 TAIN 2.0 receipt and a changed-digest control. No inputs, wallet, payment, or outbound request. Historical evidence, not a fresh clock. Bundled sample keys do not independently establish issuer identity.

popcorn_sample input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {},
  "additionalProperties": false
}

popcorn_sample annotations

{
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

popcorn_catalog

Advertised by the server during the last successful anonymous check.

Advertised read-only

Read the live catalog, offer, and published verification keys. Free; no payment.

popcorn_catalog input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {},
  "additionalProperties": false
}

popcorn_catalog annotations

{
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

popcorn_hash

Advertised by the server during the last successful anonymous check.

Advertised read-only

Hash public bytes on this remote server. Submitted text reaches the server: hash private work locally instead. Free; no onward request or payment.

popcorn_hash input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {
    "payload_text": {
      "type": "string",
      "maxLength": 65536
    },
    "payload_base64url": {
      "type": "string",
      "maxLength": 65536
    }
  },
  "additionalProperties": false
}

popcorn_hash annotations

{
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

popcorn_verify

Advertised by the server during the last successful anonymous check.

Advertised read-only

Verify a time or witness receipt using caller-trusted JWKS and expected values. Digest-only for witness payloads. No outbound request or payment. Caller keys do not establish issuer identity; a signature grants no authority.

popcorn_verify input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "required": [
    "receipt_type",
    "response",
    "jwks",
    "verification"
  ],
  "properties": {
    "jwks": {
      "type": "object",
      "propertyNames": {
        "type": "string"
      },
      "additionalProperties": {}
    },
    "response": {
      "type": "object",
      "propertyNames": {
        "type": "string"
      },
      "additionalProperties": {}
    },
    "receipt_type": {
      "enum": [
        "time",
        "witness"
      ],
      "type": "string"
    },
    "verification": {
      "type": "object",
      "propertyNames": {
        "type": "string"
      },
      "additionalProperties": {}
    }
  },
  "additionalProperties": false
}

popcorn_verify annotations

{
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

popcorn_verify_v2

Advertised by the server during the last successful anonymous check.

Advertised read-only

Verify TAIN 2.0 evidence against keys fetched from the fixed POPCORN issuer URL. Caller jwks is replaced with published keys, including predecessors. Send a digest, never private work. Free; does not grant authority, establish current time, or verify settlement on chain.

popcorn_verify_v2 input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "required": [
    "response",
    "jwks",
    "expected_nonce",
    "expected_payload_digest"
  ],
  "properties": {
    "jwks": {
      "type": "object",
      "propertyNames": {
        "type": "string"
      },
      "additionalProperties": {}
    },
    "response": {
      "type": "object",
      "propertyNames": {
        "type": "string"
      },
      "additionalProperties": {}
    },
    "expected_nonce": {
      "type": "string"
    },
    "expected_node_id": {
      "type": "string"
    },
    "previous_receipt": {
      "type": "object",
      "required": [
        "response",
        "jwks",
        "verification"
      ],
      "properties": {
        "jwks": {
          "type": "object",
          "propertyNames": {
            "type": "string"
          },
          "additionalProperties": {}
        },
        "response": {
          "type": "object",
          "propertyNames": {
            "type": "string"
          },
          "additionalProperties": {}
        },
        "verification": {
          "type": "object",
          "required": [
            "expected_nonce",
            "expected_payload_digest"
          ],
          "properties": {
            "expected_nonce": {
              "type": "string"
            },
            "expected_node_id": {
              "type": "string"
            },
            "previous_receipt": {
              "type": "object",
              "required": [
                "response",
                "jwks",
                "verification"
              ],
              "properties": {
                "jwks": {
                  "type": "object",
                  "propertyNames": {
                    "type": "string"
                  },
                  "additionalProperties": {}
                },
                "response": {
                  "type": "object",
                  "propertyNames": {
                    "type": "string"
                  },
                  "additionalProperties": {}
                },
                "verification": {
                  "type": "object",
                  "required": [
                    "expected_nonce",
                    "expected_payload_digest"
                  ],
                  "properties": {
                    "expected_nonce": {
                      "type": "string"
                    },
                    "expected_node_id": {
                      "type": "string"
                    },
                    "previous_receipt": {
                      "type": "object",
                      "required": [
                        "response",
                        "jwks",
                        "verification"
                      ],
                      "properties": {
                        "jwks": {
                          "type": "object",
                          "propertyNames": {
                            "type": "string"
                          },
                          "additionalProperties": {}
                        },
                        "response": {
                          "type": "object",
                          "propertyNames": {
                            "type": "string"
                          },
                          "additionalProperties": {}
                        },
                        "verification": {
                          "type": "object",
                          "required": [
                            "expected_nonce",
                            "expected_payload_digest"
                          ],
                          "properties": {
                            "expected_nonce": {
                              "type": "string"
                            },
                            "expected_node_id": {
                              "type": "string"
                            },
                            "previous_receipt": {
                              "type": "object",
                              "required": [
                                "response",
                                "jwks",
                                "verification"
                              ],
                              "properties": {
                                "jwks": {
                                  "type": "object",
                                  "propertyNames": {
                                    "type": "string"
                                  },
                                  "additionalProperties": {}
                                },
                                "response": {
                                  "type": "object",
                                  "propertyNames": {
                                    "type": "string"
                                  },
                                  "additionalProperties": {}
                                },
                                "verification": {
                                  "type": "object",
                                  "required": [
                                    "expected_nonce",
                                    "expected_payload_digest"
                                  ],
                                  "properties": {
                                    "expected_nonce": {
                                      "type": "string"
                                    },
                                    "expected_node_id": {
                                      "type": "string"
                                    },
                                    "previous_receipt": {
                                      "type": "object",
                                      "required": [
                                        "response",
                                        "jwks",
                                        "verification"
                                      ],
                                      "properties": {
                                        "jwks": {
                                          "type": "object",
                                          "propertyNames": {
                                            "type": "string"
                                          },
                                          "additionalProperties": {}
                                        },
                                        "response": {
                                          "type": "object",
                                          "propertyNames": {
                                            "type": "string"
                                          },
                                          "additionalProperties": {}
                                        },
                                        "verification": {
                                          "type": "object",
                                          "required": [
                                            "expected_nonce",
                                            "expected_payload_digest"
                                          ],
                                          "properties": {
                                            "expected_nonce": {
                                              "type": "string"
                                            },
                                            "expected_node_id": {
                                              "type": "string"
                                            },
                                            "previous_receipt": {
                                              "type": "object",
                                              "required": [
                                                "response",
                                                "jwks",
                                                "verification"
                                              ],
                                              "properties": {
                                                "jwks": {
                                                  "type": "object",
                                                  "propertyNames": {
                                                    "type": "string"
                                                  },
                                                  "additionalProperties": {}
                                                },
                                                "response": {
                                                  "type": "object",
                                                  "propertyNames": {
                                                    "type": "string"
                                                  },
                                                  "additionalProperties": {}
                                                },
                                                "verification": {
                                                  "type": "object",
                                                  "required": [
                                                    "expected_nonce",
                                                    "expected_payload_digest"
                                                  ],
                                                  "properties": {
                                                    "expected_nonce": {
                                                      "type": "string"
                                                    },
                                                    "expected_node_id": {
                                                      "type": "string"
                                                    },
                                                    "previous_receipt": {
                                                      "type": "object",
                                                      "required": [
                                                        "response",
                                                        "jwks",
                                                        "verification"
                                                      ],
                                                      "properties": {
                                                        "jwks": {
                                                          "type": "object",
                                                          "propertyNames": {
                                                            "type": "string"
                                                          },
                                                          "additionalProperties": {}
                                                        },
                                                        "response": {
                                                          "type": "object",
                                                          "propertyNames": {
                                                            "type": "string"
                                                          },
                                                          "additionalProperties": {}
                                                        },
                                                        "verification": {
                                                          "type": "object",
                                                          "required": [
                                                            "expected_nonce",
                                                            "expected_payload_digest"
                                                          ],
                                                          "properties": {
                                                            "expected_nonce": {
                                                              "type": "string"
                                                            },
                                                            "expected_node_id": {
                                                              "type": "string"
                                                            },
                                                            "previous_receipt": {
                                                              "type": "object",
                                                              "required": [
                                                                "response",
                                                                "jwks",
                                                                "verification"
                                                              ],
                                                              "properties": {
                                                                "jwks": {
                                                                  "type": "object",
                                                                  "propertyNames": {
                                                                    "type": "string"
                                                                  },
                                                                  "additionalProperties": {}
                                                                },
                                                                "response": {
                                                                  "type": "object",
                                                                  "propertyNames": {
                                                                    "type": "string"
                                                                  },
                                                                  "additionalProperties": {}
                                                                },
                                                                "verification": {
                                                                  "type": "object",
                                                                  "required": [
                                                                    "expected_nonce",
                                                                    "expected_payload_digest"
                                                                  ],
                                                                  "properties": {
                                                                    "expected_nonce": {
                                                                      "type": "string"
                                                                    },
                                                                    "expected_node_id": {
                                                                      "type": "string"
                                                                    },
                                                                    "expected_payload_digest": {
                                                                      "type": "string"
                                                                    },
                                                                    "max_clock_accuracy_radius_ms": {
                                                                      "type": "integer",
                                                                      "maximum": 9007199254740991,
                                                                      "minimum": 0
                                                                    }
                                                                  },
                                                                  "additionalProperties": false
                                                                }
                                                              },
                                                              "additionalProperties": false
                                                            },
                                                            "expected_payload_digest": {
                                                              "type": "string"
                                                            },
                                                            "max_clock_accuracy_radius_ms": {
                                                              "type": "integer",
                                                              "maximum": 9007199254740991,
                                                              "minimum": 0
                                                            }
                                                          },
                                                          "additionalProperties": false
                                                        }
                                                      },
                                                      "additionalProperties": false
                                                    },
                                                    "expected_payload_digest": {
                                                      "type": "string"
                                                    },
                                                    "max_clock_accuracy_radius_ms": {
                                                      "type": "integer",
                                                      "maximum": 9007199254740991,
                                                      "minimum": 0
                                                    }
                                                  },
                                                  "additionalProperties": false
                                                }
                                              },
                                              "additionalProperties": false
                                            },
                                            "expected_payload_digest": {
                                              "type": "string"
                                            },
                                            "max_clock_accuracy_radius_ms": {
                                              "type": "integer",
                                              "maximum": 9007199254740991,
                                              "minimum": 0
                                            }
                                          },
                                          "additionalProperties": false
                                        }
                                      },
                                      "additionalProperties": false
                                    },
                                    "expected_payload_digest": {
                                      "type": "string"
                                    },
                                    "max_clock_accuracy_radius_ms": {
                                      "type": "integer",
                                      "maximum": 9007199254740991,
                                      "minimum": 0
                                    }
                                  },
                                  "additionalProperties": false
                                }
                              },
                              "additionalProperties": false
                            },
                            "expected_payload_digest": {
                              "type": "string"
                            },
                            "max_clock_accuracy_radius_ms": {
                              "type": "integer",
                              "maximum": 9007199254740991,
                              "minimum": 0
                            }
                          },
                          "additionalProperties": false
                        }
                      },
                      "additionalProperties": false
                    },
                    "expected_payload_digest": {
                      "type": "string"
                    },
                    "max_clock_accuracy_radius_ms": {
                      "type": "integer",
                      "maximum": 9007199254740991,
                      "minimum": 0
                    }
                  },
                  "additionalProperties": false
                }
              },
              "additionalProperties": false
            },
            "expected_payload_digest": {
              "type": "string"
            },
            "max_clock_accuracy_radius_ms": {
              "type": "integer",
              "maximum": 9007199254740991,
              "minimum": 0
            }
          },
          "additionalProperties": false
        }
      },
      "additionalProperties": false
    },
    "expected_payload_digest": {
      "type": "string"
    },
    "max_clock_accuracy_radius_ms": {
      "type": "integer",
      "maximum": 9007199254740991,
      "minimum": 0
    }
  },
  "additionalProperties": false
}

popcorn_verify_v2 annotations

{
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

popcorn_time

Advertised by the server during the last successful anonymous check.

Advertised destructiveOpen-world

Request signed current-time evidence. Defaults to a free unpaid 402 challenge. A fresh receipt costs exactly $0.001 USDC on Base. Payment requires owner approval, approve_payment:true, and a caller-signed payment_signature. No server wallet or private key. No automatic retry. Verify evidence and account for client round-trip time before a deadline decision.

popcorn_time input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {
    "freshness_ms": {
      "type": "integer",
      "default": 30000,
      "maximum": 60000,
      "minimum": 100
    },
    "approve_payment": {
      "type": "boolean",
      "default": false
    },
    "payment_signature": {
      "type": "string",
      "maxLength": 16384,
      "description": "Caller-signed x402 PAYMENT-SIGNATURE. Never send a wallet private key. Requires approve_payment:true for this single call."
    }
  },
  "additionalProperties": false
}

popcorn_time annotations

{
  "readOnlyHint": false,
  "openWorldHint": true,
  "idempotentHint": false,
  "destructiveHint": true
}

popcorn_witness

Advertised by the server during the last successful anonymous check.

Advertised destructiveOpen-world

Witness a SHA-256 digest and fresh caller nonce at a time. Defaults to a free unpaid 402 challenge. One fresh receipt costs exactly $0.001 USDC on Base; requires owner approval, approve_payment:true, and caller-signed payment_signature. Keep work and wallet keys local. No automatic retry. Evidence does not authorize or prove execution of an action.

popcorn_witness input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "required": [
    "digest",
    "nonce"
  ],
  "properties": {
    "nonce": {
      "type": "string",
      "pattern": "^[A-Za-z0-9_-]{43}$"
    },
    "digest": {
      "type": "string",
      "pattern": "^[A-Za-z0-9_-]{43}$"
    },
    "approve_payment": {
      "type": "boolean",
      "default": false
    },
    "payment_signature": {
      "type": "string",
      "maxLength": 16384,
      "description": "Caller-signed x402 PAYMENT-SIGNATURE. Never send a wallet private key. Requires approve_payment:true for this single call."
    },
    "previous_attestation_digest": {
      "anyOf": [
        {
          "type": "string",
          "pattern": "^[A-Za-z0-9_-]{43}$"
        },
        {
          "type": "null"
        }
      ]
    }
  },
  "additionalProperties": false
}

popcorn_witness annotations

{
  "readOnlyHint": false,
  "openWorldHint": true,
  "idempotentHint": false,
  "destructiveHint": true
}

Prompts

Not advertised

No prompt definitions available.

Resources

Not advertised

No resource definitions available.

30-day availability

Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.

Successful checks: 1 of 1 (100%)
Average latency: 446 ms
95th percentile latency: 446 ms

Maintenance history

Public check and source-refresh events. Editorial and ownership records remain private.

Nov 1, 2026, 6:47 AM UTC · probe · passed · 446 ms · metadata changed · 7 tool(s)

Connect from your client

Each snippet registers the same endpoint; pick the client you use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers the remote server. Use --scope project to write .mcp.json for the repo.

Claude Code configuration

claude mcp add --transport http popcorn-mcp-767-2676 https://767-2676.com/mcp

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).

Codex configuration

codex mcp add popcorn-mcp-767-2676 --url https://767-2676.com/mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable popcorn-mcp-767-2676 in your MCP settings.

Cursor configuration

{
  "mcpServers": {
    "popcorn-mcp-767-2676": {
      "url": "https://767-2676.com/mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure).

Cline configuration

{
  "mcpServers": {
    "popcorn-mcp-767-2676": {
      "type": "streamableHttp",
      "url": "https://767-2676.com/mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start popcorn-mcp-767-2676 and inspect its tools.

VS Code configuration

{
  "servers": {
    "popcorn-mcp-767-2676": {
      "type": "http",
      "url": "https://767-2676.com/mcp"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.

Gemini CLI configuration

gemini mcp add --transport http popcorn-mcp-767-2676 https://767-2676.com/mcp

Claude Desktop

Merge this into claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\), then restart Claude Desktop.

Claude Desktop configuration

{
  "mcpServers": {
    "popcorn-mcp-767-2676": {
      "url": "https://767-2676.com/mcp"
    }
  }
}

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.

Windsurf configuration

{
  "mcpServers": {
    "popcorn-mcp-767-2676": {
      "serverUrl": "https://767-2676.com/mcp"
    }
  }
}

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POPCORN MCP

Endpoint and access

What you can do with it

Source and maintenance

Protocol and capabilities

Tools

Prompts

Resources

30-day availability

Maintenance history

Connect from your client

Claude Code

Codex

Cursor

Cline

VS Code

Gemini CLI

Claude Desktop

Windsurf

Let your agent find its tools

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