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POPCORN Witness Verifier

by violetclaire · remote · no sign-in to list tools · v2.0.1 · published by GitHub user violetclaire

MCP server for verifying receipts: POPCORN-WITNESS/2.0 signature, digest, and time. Free, read only.

Changes · 1
CompareRegistry entry

1 tool: 1 change things.

Scanned Oct 21, 2026

No check matched anything in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http popcorn-tain-verifier https://popcorn-tain-verify-mcp-v2.violetherod.workers.dev/mcp

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

1 tool

Changes things 1Claude Code: ask
  • popcorn_verify_v2Verify a POPCORN-WITNESS/2.0 receipt against a caller-computed SHA-256 payload digest, nonce, and independently trusted issuer keys.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Verify a POPCORN-WITNESS/2.0 receipt against a caller-computed SHA-256 payload digest, nonce, and independently trusted issuer keys. Send only the digest, never private payload bytes. Caller-supplied keys do not establish issuer identity. This does not prove on-chain settlement, establish current time, or grant authority. Free and read-only.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Install

Pinned to version 2.0.1. Values in angle brackets are yours to fill in.

claude mcp add --transport http popcorn-tain-verifier https://popcorn-tain-verify-mcp-v2.violetherod.workers.dev/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [],
    "ask": [
      "mcp__popcorn-tain-verifier__popcorn_verify_v2"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. It assumes the server is installed as popcorn-tain-verifier. Review it before you use it.