m2m.monster (Devnet sandbox)
REMOTE · SANDBOX.M2M.MONSTER
Non-custodial x402 payments between AI agents on Solana. Returns unsigned transactions.
Available components
Last scanned (9 hours ago)
Scores higher than 46% of remote servers
Reachable. Last reached 17 Oct 2026.
Category Crypto and Web3
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security57
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation not fully verified: no authorisation is required to call this server, and 3 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe. See how to fix → View diagnostics → Unverified
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability69
- AI-judged instruction clarity (good).Pass
- Tool/resource definitions use about 826 tokens (~82/item across 10 items; 10 tools + 0 resources), lean.Pass
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management13
- Stability observed for 4 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage95
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 86% of tool parameters carry a description.Partial
Tool Safety75
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- 0 of 1 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation; "build_refund" implies "refund" and declares readOnlyHint instead, contradicting what its own name says it does. See how to fix → Fail
- An AI judge read all 10 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 16 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.
- 14 Oct 26 +1
- Tool “build_payment” rewrote its description, which is the text the model reads security
- Tool “build_refund” rewrote its description, which is the text the model reads security
- Tool “submit_payment” rewrote its description, which is the text the model reads security
- Stability: unverified → 0.03 ▲ functional
- 13 Oct 26 61
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 17 Oct 2026 · Probed https://sandbox.m2m.monster/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=sandbox.m2m.monster | CN=YR2,O=Let's Encrypt,C=US | 11 Oct 2026 | 9 Jan 2027 | RSA 4096 | SHA256-RSA | 60b57fdb523244d222fb0f9dd01b8013d25 |
| SANs: sandbox.m2m.monster | ||||||
| CN=YR2,O=Let's Encrypt,C=US (CA) | CN=Root YR,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | RSA 2048 | SHA256-RSA | 4ebd24947e24d394802d84a52fd5b319 |
| CN=Root YR,O=ISRG,C=US (CA) | CN=ISRG Root X1,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | RSA 4096 | SHA256-RSA | f24b6d17f9d9ad7cb1c9fea78782699f |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of sandbox.m2m.monster. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| monster. | present | 27704 | 13 | Verified |
| m2m.monster. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://sandbox.m2m.monster/mcp | Verified | 200 | |
| http (plaintext) | http://sandbox.m2m.monster/mcp | HTTPS enforced | 301 | https://sandbox.m2m.monster/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
build_payment ~156
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.
| Name | Type | Req | Description |
|---|---|---|---|
| max_compute_unit_price | string | – | Lower priority fee cap in micro-lamports per compute unit |
| payer | string | yes | The payer wallet; it signs and pays the network fee |
| quote | object | yes | The signed quote exactly as returned by quote_payment |
No output schema declared.
No examples provided.
build_refund ~111
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.
| Name | Type | Req | Description |
|---|---|---|---|
| amount | string | yes | Refund amount, at most the original gross amount |
| receipt | string | yes | Receipt JWS of the original payment |
No output schema declared.
No examples provided.
get_pricing ~28
Agent-to-agent fee formula, referral program and the whitelisted token mints of this network.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
get_referral_status ~42
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.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
get_status ~14
Service status and API version.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
quote_payment ~151
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.
| Name | Type | Req | Description |
|---|---|---|---|
| amount | string | yes | Integer amount in base units of the mint |
| idempotency_key | string | – | Reuse the same key when retrying |
| mint | string | yes | Payment token mint (exact whitelisted address) |
| network | string | yes | CAIP-2 network id, e.g. solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1 |
| payee | string | yes | Wallet that receives the payment |
No output schema declared.
No examples provided.
register_agent ~122
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.
| Name | Type | Req | Description |
|---|---|---|---|
| agent_id | string | – | – |
| capabilities | array | – | – |
| referred_by | string | – | Pubkey of the agent that referred you |
| signature | string | – | Base58 ed25519 signature of the message |
| solana_pubkey | string | yes | Base58 Solana public key |
No output schema declared.
No examples provided.
submit_payment ~88
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.
| Name | Type | Req | Description |
|---|---|---|---|
| idempotency_key | string | yes | – |
| quote | object | yes | The signed quote exactly as returned by quote_payment |
| transaction | string | yes | Base64 transaction signed by the payer |
No output schema declared.
No examples provided.
verify_payment ~74
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.
| Name | Type | Req | Description |
|---|---|---|---|
| quote | object | yes | The signed quote exactly as returned by quote_payment |
| transaction | string | yes | Base64 wire transaction |
No output schema declared.
No examples provided.
verify_receipt ~40
Verify a receipt: the m2m.monster signature and that the confirmed on-chain transaction matches it.
| Name | Type | Req | Description |
|---|---|---|---|
| receipt | string | yes | Receipt JWS |
No output schema declared.
No examples provided.
How do I install the m2m.monster (Devnet sandbox) MCP server?
m2m.monster (Devnet sandbox) is a hosted endpoint at https://sandbox.m2m.monster/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · sandbox.m2m.monster
claude mcp add --transport http monster-m2m-m2m-monster 'https://sandbox.m2m.monster/mcp'
What is the m2m.monster (Devnet sandbox) MCP server?
m2m.monster (Devnet sandbox) is an MCP server listed in the public MCP registry as monster.m2m/m2m-monster. Non-custodial x402 payments between AI agents on Solana. Returns unsigned transactions. This page covers its hosted endpoint (https://sandbox.m2m.monster/mcp).
Is the m2m.monster (Devnet sandbox) MCP server safe to use?
m2m.monster (Devnet sandbox) scores 63 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the m2m.monster (Devnet sandbox) MCP server expose?
m2m.monster (Devnet sandbox) exposes 10 tools: get_pricing, quote_payment, build_payment, verify_payment, submit_payment, and 5 more. Their descriptions and schemas cost roughly 826 tokens of context every time the server is loaded.
Does the m2m.monster (Devnet sandbox) MCP server require authentication?
No. We connected to m2m.monster (Devnet sandbox) without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the m2m.monster (Devnet sandbox) MCP server still maintained?
m2m.monster (Devnet sandbox) is still listed as active in the MCP registry. We last reached this channel on 17 October 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.