Boundary Guard x402

io.github.larrylemonbot/boundary-guard-x402

Preflight readiness checker for x402 and MCP tool sellers before they list on marketplaces or route paid agent traffic. Exposes tools to scan public metadata (OpenAPI, llms.txt, agents.txt, MCP discovery endpoints), probe 402 payment challenges without signing or spending, generate launch packs with claim-bounded listing copy, and create deterministic trust receipts. Built by LarryBuildsAI as a seller-side evidence layer. You'd use this when packaging a paid agent tool for submission to Bazaar, Agentic.Market, or MCP directories and need a readiness report showing what buyers will see, what's missing, and which claims are safe to make. Not a payment processor, security audit, or marketplace itself.

tools: 6
auth: Secret needed
transport: HTTP
last updated: May 16, 2026

Open website

Install

From registry metadata

$ npx add-mcp https://x402-resource-scanner.vercel.app/mcp --name boundary-guard-x402 --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 boundary-guard-x402 https://x402-resource-scanner.vercel.app/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.

Details

Website: x402-resource-scanner.vercel.app
Transport: HTTP
Auth: Required
Registry: MCP registry, active
Tools verified: Nov 6, 2026

Boundary Guard x402

Install

Tools

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