api-contract-qa

Check deployed contract

check_deployed_contract

Compare a live service's published API contract against a spec file and return matches, drift, or incompatible verdicts for GraphQL, WSDL, OpenAPI, Swagger, or AsyncAPI endpoints.

Instructions

Compare what a running service publishes with the spec file: GraphQL introspection (url = the GraphQL endpoint), a WSDL URL (e.g. http://host/orders?wsdl), or a published OpenAPI/Swagger/AsyncAPI document (e.g. http://host/v3/api-docs). Verdict: matches | drift | incompatible. gRPC is not supported (needs reflection). Header values may use ${ENV:NAME}.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "spec": "<spec>",
      "url": "<url>"
    },
    "name": "check_deployed_contract"
  }
}

Input Schema

Name	Required	Description	Default
`url`	Yes
`spec`	Yes
`headers`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 13, 2026

TDQS

A4.1/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations supplied, the description carries the full burden and does well: it discloses the three possible verdicts (matches | drift | incompatible), the supported protocol families, the gRPC limitation, and the ${ENV:NAME} interpolation behavior for headers. It does not mention authentication requirements for the target endpoint or whether the check is purely read-only, which keeps it short of a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the core comparison, then protocol examples, then verdict vocabulary, then the gRPC exclusion and header note. Dense but every clause carries information; the parenthetical examples are slightly verbose but justified for disambiguating url formats.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, so the description must sketch the return value, and it does by naming the three verdicts. For a 3-parameter comparison tool this is close to complete, though it leaves open what a drift verdict looks like in detail and how the spec file is located/formatted.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate, and it largely does: url is explained differently per protocol (GraphQL endpoint, WSDL URL with example, OpenAPI doc with example) and headers gets the ${ENV:NAME} convention. The required spec parameter is never elaborated (file path vs URL, expected format), leaving one real gap.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb+resource pair: compare what a running service publishes against the spec file. It then enumerates the exact artifact types understood (GraphQL introspection, WSDL, OpenAPI/Swagger/AsyncAPI), which lets an agent distinguish this live-service comparison from a static sibling like diff_contracts 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.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage context is implied rather than stated: 'running service' signals live verification, and gRPC is explicitly excluded as needing reflection. However, it never states when an agent should pick this over check_live_conformance or diff_contracts, so the routing decision is left to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server