Claude MarketplacesSubmit
larrylemonbot avatar

GateCheck by LarryBuildsAI

larrylemonbot/gatecheck

You'd reach for this when you're building a paid MCP tool or x402 service and need to validate it meets marketplace standards before submitting. It runs preflight checks against your implementation, presumably verifying protocol compliance, pricing metadata, and payment flow configuration. The streamable-http transport suggests it's designed for quick validation requests without heavy setup. Think of it as a linter for monetized MCP servers, catching issues with payment endpoints or manifest structure before you go live. Useful if you're shipping commercial tools on Claude marketplaces and want to avoid rejection or broken payment flows.

GitHub stars
1
tools
6
auth
Secret needed
transport
HTTP
last updated
Jul 14, 2026
View on GitHub

Install

From registry metadata
$ npx add-mcp https://proofbeforepay.vercel.app/gatecheck/mcp --name gatecheck --header 'Authorization: Bearer ${API_TOKEN}'

Run in your terminal. add-mcp asks which agents to add it to, then asks for each value it needs. Add -g to install it for every project.

Review the command, arguments and environment values before installing. MCP servers run with your local permissions.

Other ways

Claude Code

$ claude mcp add --transport http gatecheck https://proofbeforepay.vercel.app/gatecheck/mcp --header 'Authorization: YOUR_AUTHORIZATION'

Run in your terminal. Add --scope user to make it available in every project.

Tools

Verified live · 6 tools

Verified live against the running server on Nov 6, 2026.

boundary_guard_checkCreate a deterministic, read-only pre-action receipt from request, policy, and optional result evidence. Use before an agent posts, spends, lists, or writes so the decision can be audited; no external action is executed.4 params

Create a deterministic, read-only pre-action receipt from request, policy, and optional result evidence. Use before an agent posts, spends, lists, or writes so the decision can be audited; no external action is executed.

Parameters* required
nextStepstring
Optional guidance stored in the receipt.
policyobject
Decision object, e.g. allow/retry/review/block and reason.
request*object
Action metadata the agent is about to perform.
resultobject
Optional result or dry-run summary to hash into evidence.
scan_x402_resourceRead-only scan of a public API/provider URL for x402, OpenAPI, pricing, and agent-discovery metadata. Pass url, and optionally marketplace_url plus expected_resources, to get a readiness score, issues, and fixes; no private endpoints are called.3 params

Read-only scan of a public API/provider URL for x402, OpenAPI, pricing, and agent-discovery metadata. Pass url, and optionally marketplace_url plus expected_resources, to get a readiness score, issues, and fixes; no private endpoints are called.

Parameters* required
expected_resourcesinteger
Optional expected resource count.
marketplace_urlstring
Optional marketplace/listing URL to compare against public metadata.
url*string
Target API/provider base URL to scan.
probe_x402_paid_pathProbe a public x402 paid endpoint without signing or paying, then parse the HTTP 402 challenge. Pass target plus optional expected network/asset/price to verify payment metadata and receive a deterministic health receipt.4 params

Probe a public x402 paid endpoint without signing or paying, then parse the HTTP 402 challenge. Pass target plus optional expected network/asset/price to verify payment metadata and receive a deterministic health receipt.

Parameters* required
expectedobject
Optional expected x402 metadata such as network, asset, and priceUsd.
methodstring
Safe unpaid probe method. Defaults to GET.one of GET · HEAD · OPTIONS
modestring
Probe mode for v1. Defaults to unpaid_402.one of unpaid_402 · metadata_only
target*string
Specific paid endpoint URL to probe without payment.
check_agent_tool_readinessGateCheck readiness: check whether an x402/agent-facing tool is ready for agent routing, marketplace listing, and paid-path monitoring, including public agent discovery surfaces (/llms.txt, /agents.txt, /.well-known/mcp.json, /mcp). Pass target plus optional tier, marketplace_...7 params

GateCheck readiness: check whether an x402/agent-facing tool is ready for agent routing, marketplace listing, and paid-path monitoring, including public agent discovery surfaces (/llms.txt, /agents.txt, /.well-known/mcp.json, /mcp). Pass target plus optional tier, marketplace_...

Parameters* required
expectedobject
Optional expected x402 network/asset/price metadata for paid_path probes.
expected_resourcesinteger
Optional expected resource count.
marketplace_urlstring
Optional marketplace/listing URL to compare against public metadata.
methodstring
Safe unpaid probe method when paid_path is supplied. Defaults to GET.one of GET · HEAD · OPTIONS
paid_pathstring
Optional specific paid endpoint to probe without payment for deep/report tiers.
target*string
Target API/provider base URL to scan.
tierstring
Readiness depth. quick=$1, deep=$5, report=$10. Defaults to quick.one of quick · deep · report
generate_x402_launch_packGenerate marketplace-safe launch assets for an x402/MCP seller: listing copy, buyer FAQ, checklist, approval packet, and claim boundaries. Pass target plus optional product_name, audience, primary_use_case, marketplace_url, and paid_path; service/premium tiers include readines...11 params

Generate marketplace-safe launch assets for an x402/MCP seller: listing copy, buyer FAQ, checklist, approval packet, and claim boundaries. Pass target plus optional product_name, audience, primary_use_case, marketplace_url, and paid_path; service/premium tiers include readines...

Parameters* required
audiencestring
Primary buyer/audience for listing copy.
desired_marketplacesarray
Optional marketplace names to include in launch planning.
expectedobject
Optional expected x402 network/asset/price metadata for paid_path probes.
expected_resourcesinteger
Optional expected resource count.
marketplace_urlstring
Optional marketplace/listing URL to compare against public metadata.
methodstring
Safe unpaid probe method when paid_path is supplied. Defaults to GET.one of GET · HEAD · OPTIONS
paid_pathstring
Optional paid endpoint to validate via unpaid 402 challenge for service/premium packs.
primary_use_casestring
Primary buyer outcome/use case.
product_namestring
Buyer-facing product title.
target*string
Target API/provider base URL to package for launch.
tierstring
Launch pack depth. single=$9, service=$29, premium=$49. Defaults to single.one of single · service · premium
generate_trust_receiptGenerate a deterministic trust receipt from sanitized request/policy/result/payment summaries. Do not submit raw auth headers, cookies, API keys, private keys, payment signatures, payment response headers, customer prompts, customer documents, or payer-identifying evidence.5 params

Generate a deterministic trust receipt from sanitized request/policy/result/payment summaries. Do not submit raw auth headers, cookies, API keys, private keys, payment signatures, payment response headers, customer prompts, customer documents, or payer-identifying evidence.

Parameters* required
nextStepstring
Optional receipt next-step guidance.
paymentobject
Optional sanitized payment summary or caller-provided hashes only; do not include raw payment signatures, raw payment response headers, private keys, API keys, cookies, payer-identifying evidence,...
policyobject
Sanitized policy or decision summary to hash.
request*object
Sanitized request/action summary to hash; omit raw prompts, documents, credentials, cookies, auth headers, signatures, and secrets.
resultobject
Sanitized outcome/result summary to hash; omit customer data and secret-like values.

Sponsors

Promote your product hereReach 125k+ visitors monthlyPromote your product hereReach 125k+ visitors monthlyAgent CaffeineSponsoredClose your lid, come back to finished workSnugSponsoredThe clipboard manager for the AI eraPromote your product hereReach 125k+ visitors monthlyWaxSponsoredBlock anything with supervision, without erasing your iPhonePromote your product hereReach 125k+ visitors monthlyknobsSponsoredSee your site on any phone, any day, in any language

Readme

GateCheck by LarryBuildsAI

GateCheck is a hosted remote MCP server and x402 readiness surface for paid agent-tool sellers.

Use it before public submission, promotion, or paid agent routing to verify that a paid x402 or MCP tool is discoverable, inspectable, and claim-bounded.

Hosted MCP Endpoint

  • Remote MCP URL: https://proofbeforepay.vercel.app/gatecheck/mcp
  • Transport: streamable-http
  • Public introspection: initialize and tools/list
  • Protected tool execution: bearer auth may be required for direct production calls
  • Product homepage: https://proofbeforepay.vercel.app/gatecheck
  • Scorecard: https://github.com/LarryLemonBot/gatecheck/blob/main/scorecard.md
  • Product card: https://proofbeforepay.vercel.app/gatecheck/product-card.md
  • Marketplace index: https://proofbeforepay.vercel.app/gatecheck/marketplaces.json

MCP Client Config

{
  "mcpServers": {
    "gatecheck": {
      "type": "streamable-http",
      "url": "https://proofbeforepay.vercel.app/gatecheck/mcp"
    }
  }
}

If your client supports request headers and you have a GateCheck production token, add:

{
  "Authorization": "Bearer YOUR_GATECHECK_TOKEN"
}

View the full README on GitHub

Details

Repository
github.com/larrylemonbot/gatecheck
Website
proofbeforepay.vercel.app/gatecheck
Transport
HTTP
Auth
Required
Registry
MCP registry, active
Tools verified
Nov 6, 2026

More from larrylemonbot