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

The description goes well beyond the annotations by disclosing that it performs a 'credential-free probe of the endpoint,' explaining what that probe covers (authentication, OAuth methods, spec deviations, tool names/schemas) and how results are categorized. It also clarifies the semantics of UNKNOWN ('never means it will not work') and tells the agent to report what it found. This is rich, transparent behavioral context, and no contradiction with readOnlyHint/openWorldHint exists.

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 dense but intentional, with the core purpose front-loaded in the first sentence. It packs in outcome definitions, methodology, and output behavior, all of which are relevant. While it is longer than typical tool descriptions, every sentence contributes substantive information, so it earns a 4 rather than a 5 for being slightly verbose relative to a minimal expression.

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 complexity (multiple clients, varied inputs, nuanced outcomes) and the absence of an output schema, the description is exceptionally complete. It explains the full range of output states, the setup steps included in NEEDS_SETUP, the ready-to-paste config output, the credential-free methodology, and the meaning of UNKNOWN. There are no obvious gaps an agent would need to fill before invoking it correctly.

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?

The input schema already provides 100% description coverage, explaining that 'server' accepts an endpoint URL, registry name, or npm package name, and that 'client' is an enum with an 'omit for every client' note. The description largely repeats this information without adding new parameter-level constraints or usage nuances. Thus the baseline score of 3 is appropriate; it neither detracts nor adds significant value beyond the schema.

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 tool's purpose with a specific verb and resource: it checks whether an MCP server will work in a given client and what setup is required. It enumerates specific inputs (endpoint URL, registry name, npm package name) and outputs (WORKS, NEEDS_SETUP, BLOCKED, UNKNOWN), distinguishing it from sibling tools by focusing on per-client compatibility and config generation. This makes the tool's role unambiguous.

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 a clear context: 'Before wiring an MCP server into a client, find out whether it will work there and exactly what it takes.' This tells the agent when to use the tool, but it does not explicitly name alternative tools or state when not to use it. Since it offers strong contextual guidance without exclusions, it earns a 4 rather than a 5.

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