Lints whether a paid API's 402 response speaks the x402 protocol correctly.
Scored across 1 tool
Only one tool exists, so there is no possibility of confusion or overlap with another tool. Its purpose is stated precisely and unambiguously.
The single tool follows a clear verb_noun pattern: lint_x402_endpoint. With only one name, consistency is trivially maintained and the convention is readable.
One tool is thin for a server, even if it is narrowly scoped to x402 endpoint linting. The server name 'tools' implies a broader set, but the actual purpose is covered by this single operation.
The tool covers fetching, validating the HTTP 402 response, and reporting protocol shape errors, which fully addresses the core linting purpose. Minor gaps could include options for custom headers or batch URLs, but no critical dead ends are apparent.
Fetch a URL, expect an HTTP 402 response, and validate the JSON body against the x402 protocol shape (x402Version, accepts[] fields, resource/description). Free, no account. Returns a pass/fail report with concrete errors and warnings.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | Absolute http(s) URL of the paid endpoint to check (should return HTTP 402). |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and does well: it discloses the outbound network fetch, the expected 402 response, the free/no-account auth profile, and that the return is a pass/fail report with errors and warnings. It omits failure-mode details such as timeouts, redirect handling, or what happens when the endpoint does not return 402.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single tight sentence that front-loads the core operation (fetch + expect 402 + validate) before the secondary facts (free, no account) and the return shape. No filler.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a one-parameter diagnostic tool with no output schema, the description covers the operation, the expected input condition, the cost/auth profile, and the shape of the result. Only minor gaps remain around network edge cases (timeouts, non-402 responses, redirects).
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% and the single 'url' parameter is fully documented as an absolute http(s) URL that should return HTTP 402. The description restates that intent ('Fetch a URL, expect an HTTP 402 response') but adds no syntax or format detail beyond the schema, so the baseline 3 applies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb and resource: fetch a URL, expect HTTP 402, validate the JSON body against the x402 protocol shape, naming concrete fields (x402Version, accepts[], resource/description). An agent knows exactly what the tool produces without opening the schema.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Gives clear invocation context — 'Free, no account' tells the agent there is no auth prerequisite or cost barrier, and the described flow implies the use case is checking a paid x402 endpoint. No alternatives or exclusions are named, but there are no sibling tools to differentiate from.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
lint_x402_endpointDiagnose x402 seller endpoints: what is wrong with your 402 challenge, and how to fix it.
Audits any URL for HTTP 402 x402 V2 compliance, PAYMENT-REQUIRED headers, Bazaar schema, and MCP.
Test any x402 paid URL without paying: 402, PAYMENT-REQUIRED, USDC, amounts, payTo, EIP-712, CORS.
Trust verdict for an x402 payment endpoint: health, 402 handshake, price, proceed/caution/avoid.
Add one secure layer between your agents and this server.