OpenAPI MCP Server

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

The description adds valuable behavioral context beyond annotations: it explains path parameter substitution syntax with a concrete example, mentions JSON encoding for request bodies, and references the api_discover prerequisite. While annotations cover safety aspects (readOnlyHint=false, destructiveHint=false), the description provides practical implementation details that help the agent use the tool correctly.

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?

Extremely efficient two-sentence structure with zero waste. The first sentence states the core purpose, the second provides critical usage guidance and parameter example. Every word serves a clear purpose in helping the agent understand and use the tool.

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 flexible HTTP request tool with openWorldHint=true and no output schema, the description provides good context about the workflow (api_discover prerequisite) and parameter usage (path substitution example). However, it doesn't address potential authentication requirements, rate limits, or error handling that would be helpful for such a general-purpose tool.

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 schema already documents all 5 parameters thoroughly. The description adds minimal parameter semantics - only clarifying path parameter substitution with an example. This meets the baseline expectation when schema coverage is complete.

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 ('Make an HTTP request') and resource ('to any API endpoint'), with explicit differentiation from its sibling tool ('Use api_discover first'). It goes beyond the tool name/title by specifying the HTTP nature and endpoint targeting.

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?

Provides explicit when-to-use guidance ('Use api_discover first to see available endpoints and their parameters') and names the alternative tool (api_discover). This creates clear workflow context for when to use this tool versus its sibling.

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