m2m.monster

by m2m.monster · remote · no sign-in to list tools · v1.1.0 · published by monster.m2m

Non-custodial x402 payments between AI agents on Solana. Returns unsigned transactions.

Final · 5Changes · 2

Compare Registry entry

10 tools: 5 do something that can't be undone, 2 change things and 3 only read.

Scanned Oct 21, 2026

Deletes or cancels0Claude Code: deny
Can't be undone5Claude Code: ask: see these tools
Changes things2Claude Code: ask: see these tools
Only reads3Claude Code: allow: see these tools

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

claude mcp add --transport http m2m-monster https://api.m2m.monster/mcp

Findings

Matches of fixed checks, with the text they matched.

3 warn

Warnbuild_payment
The server marks "build_payment" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
Matched text
annotations: {"readOnlyHint":true,"openWorldHint":false}; The name "build_payment" says "payment": a word that usually means money moves, which cannot be taken back.
What this check looks for
Warnverify_payment
The server marks "verify_payment" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
Matched text
annotations: {"readOnlyHint":true,"openWorldHint":false}; The name "verify_payment" says "payment": a word that usually means money moves, which cannot be taken back.
What this check looks for
Warnbuild_refund
The server marks "build_refund" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
Matched text
annotations: {"readOnlyHint":true,"openWorldHint":false}; The name "build_refund" says "refund": a word that usually means money moves, which cannot be taken back.
What this check looks for

Tools

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

10 tools

Can't be undone 5Sends, pays, publishes or merges: once done, it cannot be taken back.Claude Code: ask

build_paymentBuild the m2m-split transaction for a quote: the payer's transfer to the payee and the USDC fee transfer to the treasury, in one atomic transaction where the payer pays its own gas…1 finding
Why it is in this group
- The name "build_payment" says "payment": a word that usually means money moves, which cannot be taken back.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
Findings
- Warn
  The server marks "build_payment" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
  Matched text
  annotations: {"readOnlyHint":true,"openWorldHint":false}; The name "build_payment" says "payment": a word that usually means money moves, which cannot be taken back.
  What this check looks for
Description, as the server wrote it
Build the m2m-split transaction for a quote: the payer's transfer to the payee and the USDC fee transfer to the treasury, in one atomic transaction where the payer pays its own gas. Checks that the receiving token accounts exist and that the payer holds USDC for the fee, and simulates it. Unsigned. Sign it locally with your own Solana key; m2m.monster never sees or uses agents' private keys.
Annotations the server declares
- readOnlyHint: true
- openWorldHint: false
build_refundBuild a refund from the payee back to the payer, linked to the original receipt.1 finding
Why it is in this group
- The name "build_refund" says "refund": a word that usually means money moves, which cannot be taken back.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
Findings
- Warn
  The server marks "build_refund" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
  Matched text
  annotations: {"readOnlyHint":true,"openWorldHint":false}; The name "build_refund" says "refund": a word that usually means money moves, which cannot be taken back.
  What this check looks for
Description, as the server wrote it
Build a refund from the payee back to the payer, linked to the original receipt. The payee signs it and pays its gas; it has no m2m.monster fee and the original fee is not returned. Unsigned. Sign it locally with your own Solana key; m2m.monster never sees or uses agents' private keys.
Annotations the server declares
- readOnlyHint: true
- openWorldHint: false
quote_paymentPrice a payment to a payee: gross amount, net amount to the payee, fee_gross, discount, fee_net, treasury, mint and a 30-second expiry.No findings
Why it is in this group
- The name "quote_payment" says "payment": a word that usually means money moves, which cannot be taken back.
Description, as the server wrote it
Price a payment to a payee: gross amount, net amount to the payee, fee_gross, discount, fee_net, treasury, mint and a 30-second expiry. Returns a signed quote.
Annotations the server declares
- readOnlyHint: false
- openWorldHint: false
submit_paymentBroadcast a transaction the payer already signed, wait for confirmation and return the signed receipt.No findings
Why it is in this group
- The name "submit_payment" says "submit": a word for a change.
- The name "submit_payment" also says "payment": a word that usually means money moves, which cannot be taken back.
Description, as the server wrote it
Broadcast a transaction the payer already signed, wait for confirmation and return the signed receipt. Only broadcasts; never signs or pays payment transactions. A retry with the same idempotency_key never pays twice.
Annotations the server declares
- readOnlyHint: false
- destructiveHint: false
- openWorldHint: true
verify_paymentFor the payee: check a payer-signed transaction against its quote (net amount, fee to the treasury, whitelisted mints, quote id and expiry) and simulate it before submitting.1 finding
Why it is in this group
- The name "verify_payment" says "payment": a word that usually means money moves, which cannot be taken back.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
Findings
- Warn
  The server marks "verify_payment" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
  Matched text
  annotations: {"readOnlyHint":true,"openWorldHint":false}; The name "verify_payment" says "payment": a word that usually means money moves, which cannot be taken back.
  What this check looks for
Description, as the server wrote it
For the payee: check a payer-signed transaction against its quote (net amount, fee to the treasury, whitelisted mints, quote id and expiry) and simulate it before submitting.
Annotations the server declares
- readOnlyHint: true
- openWorldHint: false

Changes things 2Creates or changes something that can be changed back.Claude Code: ask

register_agentOptional registration; paying and getting paid work without it.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.
Description, as the server wrote it
Optional registration; paying and getting paid work without it. It unlocks referral credits and receipt history. Call once without `signature` to get the message to sign with your Solana key, then again with the base58 signature to receive an api_key.
Annotations the server declares
- readOnlyHint: false
- openWorldHint: false
verify_receiptVerify a receipt: the m2m.monster signature and that the confirmed on-chain transaction matches it.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 receipt: the m2m.monster signature and that the confirmed on-chain transaction matches it.
Annotations the server declares
- readOnlyHint: true
- openWorldHint: true

Only reads 3Looks things up and changes nothing.Claude Code: allow

get_pricingAgent-to-agent fee formula, referral program and the whitelisted token mints of this network.No findings
Why it is in this group
- The name "get_pricing" says "get": a word for reading.
Description, as the server wrote it
Agent-to-agent fee formula, referral program and the whitelisted token mints of this network.
Annotations the server declares
- readOnlyHint: true
- openWorldHint: false
get_referral_statusYour referrer, referred agents, credits and their expiry dates.No findings
Why it is in this group
- The name "get_referral_status" says "get": a word for reading.
Description, as the server wrote it
Your referrer, referred agents, credits and their expiry dates. Credits are discounts on your own fees, never cash. Requires the api_key from register_agent.
Annotations the server declares
- readOnlyHint: true
- openWorldHint: false
get_statusService status and API version.No findings
Why it is in this group
- The name "get_status" says "get": a word for reading.
Description, as the server wrote it
Service status and API version.
Annotations the server declares
- readOnlyHint: 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 1.1.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http m2m-monster https://api.m2m.monster/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": [
      "mcp__m2m-monster__get_pricing",
      "mcp__m2m-monster__get_referral_status",
      "mcp__m2m-monster__get_status"
    ],
    "ask": [
      "mcp__m2m-monster__quote_payment",
      "mcp__m2m-monster__build_payment",
      "mcp__m2m-monster__verify_payment",
      "mcp__m2m-monster__submit_payment",
      "mcp__m2m-monster__verify_receipt",
      "mcp__m2m-monster__build_refund",
      "mcp__m2m-monster__register_agent"
    ],
    "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 m2m-monster. Review it before you use it.

Keep track

Get told when this server's tools change: a new tool, a new description, a new class.

https://anlyon.dev/servers/monster.m2m/m2m-monster/changes.xml

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Anlyon alternative

7 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.

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Source: MCP Registry. Synced Oct 21, 2026, 18:53 UTC.

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