OpenAPI MCP Server

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

The description adds valuable context beyond annotations by specifying the return format ('Returns method, path, description, and optionally parameters for each endpoint') and the optional parameter inclusion behavior. While annotations cover safety (readOnlyHint, destructiveHint) and idempotency, the description provides practical output details that help the agent understand what to expect.

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?

The description is extremely concise (two sentences) and front-loaded with the core purpose. Every sentence earns its place: the first states what it does, the second provides usage guidance and output details. There's zero wasted text.

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?

Given the tool's moderate complexity (discovery operation with 2 parameters), rich annotations (4 hints covering safety and behavior), and no output schema, the description provides good completeness. It covers purpose, usage context, and output format, though it doesn't detail potential limitations like pagination or rate limits.

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?

With 100% schema description coverage, the input schema already fully documents both parameters. The description mentions 'optionally parameters for each endpoint' which relates to the 'includeParameters' parameter, but doesn't add significant meaning beyond what's in the schema. This meets the baseline for high schema coverage.

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?

The description clearly states the specific action ('List all available API endpoints grouped by domain') and distinguishes it from the sibling tool 'api_request' by emphasizing this is for discovery before making actual requests. It explicitly mentions the verb 'list' and resource 'API endpoints' with grouping by domain.

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?

The description provides explicit guidance on when to use this tool ('Call this first to understand what APIs are available before making requests') and implicitly suggests an alternative (use 'api_request' for actual API calls). It clearly establishes the context for discovery versus execution.

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