Generic MCP server for calling x402-protected APIs with automatic payment handling
Nothing to run from here
x402 Conformance Tools is installed from its publisher's own source and answers where it runs, so this marketplace is not in the path of a single call. There is no address here to send one to, and a panel that pretended otherwise would be showing you an answer we made up. Install it and call it from your own client — the Installation tab has the entry for each one.
96/100
trust score
6
tools declared
local
runs on your machine
—
downloads a day
What it does
Non-custodial x402 checks: decode 402s, verify settlements on-chain, lint specs, test facilitators.
Quickstart
# 1 — add it to Claude Code
claude mcp add --scope user x402-conformance-tools-mcp '--' npx -y @uigstudios/x402-conformance-mcp
# 2 — ask your agent for something these tools do
# decode_402, inspect_payment_response, check_compliance and 3 more
x402 Conformance Tools costs nothing on mcprush: there is no plan to choose here, no cap to set and nothing mcprush can bill you for.
Publishernot claimed
DRAll 2 servers
drvelvetfog2 servers
2 categories
Collected from a public index. Nobody has claimed this account, so nothing here was written by its author — claim it if it is yours.
Installation
Where are you running it?
Every route below installs the same thing and ends at the same approval screen. This one runs on your machine: your client starts x402 Conformance Tools as a process under your own user, with your files and your network, so the tool surface below is what it can do to your computer rather than to a server somewhere else. Its scan result is on the Security tab — read the surface before you approve it.
Claude Codedeclared by this listing
This is a public server: you run it yourself and this marketplace is not in the path. You need Node.js — the current LTS (24) is the safe choice; npx comes with it. Claude Code registers it in one command; --scope user makes it available in every project. The '--' is in quotes so that PowerShell passes it on.
claude mcp add --scope user x402-conformance-tools-mcp '--' npx -y @uigstudios/x402-conformance-mcpReconnect, or start a new session, and the tools appear in the model’s tool list.
Free on mcprush, and it runs from its publisher’s own package: this marketplace is not in the path, so there is no key of ours to hold and no card to add.
What it writes
One config entry your client uses to start the process locally. A local server runs with your file system and your network, which is why it is priced without metering.
What you approve
6 tools, with what each one reads, writes and reaches shown before you agree — the same list on every route above. Read the tool surface.
Tool surface
What the model actually sees. Descriptions are diffed on every release — see version history.
Read from its source code. A server that builds its tool list when it starts can list more tools than this.
Parse and validate an x402 PaymentRequired (HTTP 402) response and explain every field. Flags missing economic fields (scheme/network/asset/payTo/amount), number-typed or human-decimal amounts (must be atomic-integer strings), and missing explicit decimals. Provide ONE of: url (does an unpaid…
| Parameter | Type | Required | Notes |
|---|---|---|---|
| url | string | no | Resource URL to GET unpaid; expects a 402 with a PaymentRequired body. |
| raw | string | no | A PaymentRequired as a JSON string or base64-encoded JSON. |
| json | object | no | A PaymentRequired as an object. |
Decode and validate an x402 PAYMENT-RESPONSE, surfacing success, settlement id, payer, network, and amount. Optionally recomputes the on-chain truth: pass rpcUrl + expectedPayTo for a sui:* network (queries sui_getTransactionBlock balanceChanges), or observedBalanceChanges + expectedPayTo…
| Parameter | Type | Required | Notes |
|---|---|---|---|
| raw | string | no | PAYMENT-RESPONSE as a JSON string or base64-encoded JSON. |
| json | object | no | PAYMENT-RESPONSE as an object. |
| rpcUrl | string | no | Optional. Chain RPC URL; used for the on-chain net-balance check on sui:* networks. |
| observedBalanceChanges | array | no | Optional. A balanceChanges array (any chain) to recompute net-to-payTo from, instead of an RPC call. |
| expectedPayTo | string | no | Optional. The recipient address to sum net balance change for. |
| expectedAsset | string | no | Optional. Asset/coin type to filter on (defaults to 0x2::sui::SUI for Sui). |
| expectedAmount | string | no | Optional. Expected atomic amount; defaults to the response amount. |
Heuristically scan x402 code (a file or directory) for the high-severity classes: hardcoded chain id, hardcoded decimals, magic-number decimal scaling (10**N, 1eN, *1_000_000), human-decimal/float amounts, and literal asset/token addresses. Returns findings with file:line and severity. Heuristic —…
| Parameter | Type | Required | Notes |
|---|---|---|---|
| path | string | yes | A file or directory to scan. |
| maxFiles | number | no | Cap on files scanned (default 2000). |
| maxFindings | number | no | Cap on findings returned (default 300). |
Lint a draft scheme spec (markdown) against the bundled scheme_template.md: reports missing/extra template sections and whether the draft pins down the load-bearing concepts a scheme must specify (value/recipient assertion, settlement identifier, replay protection, atomic+decimals amount encoding,…
| Parameter | Type | Required | Notes |
|---|---|---|---|
| path | string | yes | Path to the draft scheme markdown. |
| template | string | no | Optional template path relative to the plugin root (default .x402-specs/scheme_template.md). |
Structurally validate an x402 extension payload: checks the typed { info, schema } envelope and runs light known-extension field checks (offer-and-receipt, payment_identifier, gas-sponsoring, sign-in-with-x, builder_code). Pass payload as a single entry (with name), an extensions map keyed by…
| Parameter | Type | Required | Notes |
|---|---|---|---|
| payload | yes | An extension entry, an extensions map, or an array of entries. | |
| name | string | no | Optional extension name when payload is a single entry. |
Drive the x402 conformance sequence against a facilitator. Holds NO keys: automates the 402 negotiation (with resourceUrl), facilitator reachability (GET /supported), and malformed-verify rejection. The keyed steps (verify happy-path, tampered-reject, settle, idempotent re-settle) run ONLY when…
| Parameter | Type | Required | Notes |
|---|---|---|---|
| facilitatorUrl | string | yes | Base URL of the facilitator (POST /verify, /settle). |
| resourceUrl | string | no | Optional. A payment-gated resource URL to test 402 negotiation. |
| paymentPayload | object | no | Optional. A pre-signed payment payload (produced by your keyed SDK) to run the happy/tampered paths. |
| paymentRequirements | object | no | Optional. The paymentRequirements the payload pays. |
| allowSettle | boolean | no | Optional. Must be true to actually settle (settles real testnet value). Default false. |
Free
$0 forever
- Every tool, no call limit
- No card, and mcprush charges nothing for it
- Source published under Apache-2.0
- Runs on your machine — nothing of it reaches our gateway
- Nothing to cap, because mcprush bills nothing
What counts against your monthly calls
| Tool | Unit | Calls used | Out of the allowance |
|---|
Nothing here is billable: mcprush charges nothing to install x402 Conformance Tools or to call it, at any volume.
Call allowance · this installenforced at the gateway
Monthly allowance, in calls
—
—
Alert at 80% · then the tool returns a normal MCP error
Used this month: —
ATrust score 96 / 100
Release 0.1.1 · scanned 15 Nov 2026
Two independent axes, because powerful and malicious are different questions. The grade is threat only. The capability level is blast radius, and it is never a penalty on the grade — it is priced as one subtract-only term in the score, where you can see it.
Threat score100
Client score96
Findings1 threat · 2 capability
Capabilitymoderate
Coveragesource
Verificationrepo
Surface digesta1af85d012c8bfd5e369da1c875ba7485ac120b434def6ce99e4ae720d181a1f
Score vectorthreat 100 → client 96
| Term | Level | What it prices | Points |
|---|---|---|---|
| capability-exposure | moderate | capability blast radius (moderate) — client exposure if the model is manipulated | −3 |
| verification-discount | repo | publisher verification (public source) — no provenance, but the source is public and inspectable | −1 |
| coverage-honesty | source | inspection depth (source) — how much of the target the scan could see | −0 |
score = clamp(round(threatScore − E_cap − E_ver − E_cov), 0, 100). No model, no opinion, no network call at scoring time: the same methodology version against the same bytes always produces this number, and every line above is a field of the report rather than a summary of it.
What the scan could actually read
A grade is only as meaningful as its coverage, so the scanner publishes its own depth before it publishes its result.
Tool surfaceread
Implementation sourceread
Package metadataread
Live transportnot available
Tools were statically extracted from the published source (6 recovered), not enumerated from a running server. Tool-poisoning, Unicode-smuggling, capability and toxic-flow analysis ran on this inferred surface, but a mis-parsed registration could be missed or mis-attributed, so tool-derived findings are capped below “confirmed”. To grade the real runtime surface, scan the running server: --command "npx -y <package>".
Capability — what it could do if the model were manipulated
Tags derived from each tool’s schema and the implementation, not from what the tool calls itself. moderate is the level these add up to.
| Tool | Capability tags | Why the tag was assigned |
|---|---|---|
| decode_402 | untrusted-input | untrusted-input: declares openWorldHint: true (interacts with entities outside the server) |
| inspect_payment_response | untrusted-input | untrusted-input: declares openWorldHint: true (interacts with entities outside the server) |
| check_compliance | no tags | |
| lint_scheme_spec | no tags | |
| validate_extension | no tags | |
| run_conformance | external-sink | external-sink: declares readOnlyHint: false, destructiveHint: true, openWorldHint: true |
Toxic-flow graph
The lethal trifecta, checked as a graph rather than as a checklist: untrusted input, a sensitive source and an external sink have to meet before there is a path worth worrying about.
flow-1
Untrusted input can drive an external action even though no sensitive source is exposed.
Supply chain and provenance
Integrityfirst-seen
Surface digesta1af85d012c8bfd5
Scanned2026-11-15
This is the first scan of this surface here, so there is nothing yet to compare it against.
Every result on this tab comes from one deterministic pass over the published package — offline, rule by rule, and auditable line by line above. Same methodology version, same bytes, same score.
Release history
Always latest — the install command names no version, so it installs the newest release when it runs; the current release on file is 0.1.1. Pin a release below and the command asks for exactly that one.
0.1.1
undated
latestNo release note was published with this version.
—
no reviews yet
Who can review
One review per account, from a signed-in account that does not publish this listing. Nothing else is asked — you can say what you think before you install it. Publishers can reply once per review, and a review can be edited or deleted by whoever wrote it.
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Nobody has reviewed this listing. The rating on the card is the mean of the reviews written here and nothing else, so there is no rating until somebody writes the first — which takes a signed-in account that does not publish it, and nothing else.