POPCORN MCP

io.github.violetclaire/popcorn-mcpvioletclairestreamable-httpv0.1.5Scanned 1 hour ago

RFC 3161 + authorization expiry: https://767-2676.com/prove-action-before-authorization-expired

7 tools: 2 can delete or cancel things, 4 change things and 1 only read.

Reads private data · 0
Reads text others write · 2
Can send data out · 0
No findings

Anlyon alternative

6 of these tools change something. Run those as governed actions.

Declare what an action changes, and Anlyon puts it under a shared limit, binds every approval to the exact request, and grades the outcome. It works on any HTTPS API you can describe as an action.

Anlyon does not run, proxy or govern this MCP server. A tool your own code calls directly is not routed through Anlyon and is not governed by it.

Import an OpenAPI spec →

Tools

Grouped by what each tool does, most consequential first. Open one for its reasons and full description; descriptions are the publisher's own words.

7 tools

Deletes or cancels 2Removes, cancels or revokes something.Claude Code: deny

popcorn_timeRequest signed current-time evidence.Reads text others writeNo findings
Why it is in this group
- The description's first verb is "request": a word for a change.
- The server marks it destructive (destructiveHint: true).
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
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.
Annotations the server declares
- readOnlyHint: false
- destructiveHint: true
- idempotentHint: false
- openWorldHint: true
popcorn_witnessWitness a SHA-256 digest and fresh caller nonce at a time.Reads text others writeNo 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 destructive (destructiveHint: true).
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
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.
Annotations the server declares
- readOnlyHint: false
- destructiveHint: true
- idempotentHint: false
- openWorldHint: true

Changes things 4Creates or changes something that can be changed back.Claude Code: ask

popcorn_hashHash public bytes on this remote server.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
Hash public bytes on this remote server. Submitted text reaches the server: hash private work locally instead. Free; no onward request or payment.
Annotations the server declares
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
popcorn_sampleCheck the public October 14 TAIN 2.0 receipt and a changed-digest control.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
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.
Annotations the server declares
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
popcorn_verifyVerify a time or witness receipt using caller-trusted JWKS and expected values.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 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.
Annotations the server declares
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
popcorn_verify_v2Verify TAIN 2.0 evidence against keys fetched from the fixed POPCORN issuer URL.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 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.
Annotations the server declares
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false

Only reads 1Looks things up and changes nothing.Show 1 read-only tool

popcorn_catalogRead the live catalog, offer, and published verification keys.No findings
Why it is in this group
- The description's first verb is "read": a word for reading.
Description, as the server wrote it
Read the live catalog, offer, and published verification keys. Free; no payment.
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.

Exfil surface

Which tools read private data, which read text someone else can write, and which can send data out. One of each is a path a prompt injection can use.

No private-data, untrusted-input, outbound path in this server alone: no tool is tagged private-data or outbound.

Reads private data0: Reads files, mail, messages, databases, secrets, calendars or repositories.
Reads text others write2: Brings in text someone else can write: web pages, inbound email, messages, issues and comments.; popcorn_time
popcorn_witness
Can send data out0: Can carry data to people or systems: it sends, posts or publishes, or takes a recipient, channel or URL.

Other servers in the same agent add their own tools to these paths. Audit your whole setup to see them together.

Findings

Matches of fixed checks, with the text they matched.

No check matched anything in these tool definitions. That is not a safety guarantee.

History

Changes to its tool definitions and to its remote endpoint, newest first.

No change seen yet. Its tools are rescanned every day, and a remote endpoint is looked at once a week.

All changes to this server

Install

Pinned to version 0.1.5. Values in angle brackets are yours to fill in.

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

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

Run in a terminal.

Claude Code permissions

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

.claude/settings.json

{
  "permissions": {
    "allow": [
      "mcp__popcorn__popcorn_catalog"
    ],
    "ask": [
      "mcp__popcorn__popcorn_sample",
      "mcp__popcorn__popcorn_hash",
      "mcp__popcorn__popcorn_verify",
      "mcp__popcorn__popcorn_verify_v2"
    ],
    "deny": [
      "mcp__popcorn__popcorn_time",
      "mcp__popcorn__popcorn_witness"
    ]
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. A read that can send data out (it takes a URL, say) asks first too. It assumes the server is installed as popcorn. Review it before you use it.

Capability tags behind 2 rules

mcp__popcorn__popcorn_time untrusted-input
mcp__popcorn__popcorn_witness untrusted-input

Keep the decision: fail CI when the tools change, follow every change, or show a badge.

Pin in CI

Fail a build when the tools you reviewed are not the tools the server serves today.

curl -s "https://anlyon.dev/api/v1/servers/io.github.violetclaire/popcorn-mcp/verify?hash=db057d26131aa41489e8162c8712c8d4e16d7d64ef6c0bd8c32bcce64319c001" | jq -e '.changed == false'

Pinned hash db057d26131a, from Oct 24, 2026, 07:17 UTC.

Watch

Get told when its tools change: a new tool, a new description, a new class.

https://anlyon.dev/servers/io.github.violetclaire/popcorn-mcp/changes.xml

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Badge

[![anlyon.dev](https://anlyon.dev/badge/io.github.violetclaire/popcorn-mcp.svg)](https://anlyon.dev/servers/io.github.violetclaire/popcorn-mcp)

Source: MCP Registry · repository. Synced Oct 24, 2026, 07:17 UTC.