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

Annotations already cover safety (readOnly, idempotent, closed-world), so the description correctly spends its words elsewhere: result ordering (relevance first, then published rank rules, explicitly no paid placement) and the semantics of similar_to (same categories + same auth, working servers only). Pagination/limit behavior and result shape are not disclosed.

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?

Three sentences, front-loaded with the resource and source, then usage pattern, then ranking/similar_to behavior. Dense but each sentence carries information; the example could be trimmed slightly but earns its place as a mapping illustration.

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?

There is no output schema, so the description should say something about what a result contains (name, categories, measurement fields, rank fields), and it does not. With 11 optional parameters, several filters are left entirely to their enum labels. Adequate for correct invocation of the common path, incomplete for interpreting results.

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 73%, so the schema already documents most parameters, and the description's value-add is limited to q/auth/reachable (via the example) and similar_to (semantics beyond 'Registry name of a server to find alternatives for'). Limit, offset, transport, risk, capability and min_success_7d receive no explanation beyond their enum/constraint definitions.

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 ('Find remote MCP servers'), names the data source (Official MCP Registry plus MCP Station measurements), and implies distinct roles for siblings (list_categories for category IDs, get_server for detail). An agent can tell this is the discovery/listing tool without opening any 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?

Tells the agent to convert the user's need into a q string plus filters, and gives a concrete worked example ('crypto market data, no API key, working' -> q=..., auth='none', reachable=true). It also explains the similar_to alternative mode. It stops short of stating when NOT to use this tool versus search_tools or get_server.

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