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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description goes well beyond that by disclosing the paid call model ($0.02 USDC via x402 on Base or Solana), that results are signed, that rankings are not for sale, and that a method accompanies the data — genuinely useful behavioral context absent from structured fields.

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?

Front-loaded with the resource ('Leaderboards...'), then the category list, then the method/trust/pricing tail. It is a single dense sentence that reads well, though the category list plus commercial disclaimers make it longer than strictly necessary.

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 no-parameter, no-output-schema read tool, the description is nearly self-sufficient: it tells the agent what data categories come back and what payment is required to call it. Only the absence of any routing guidance against siblings keeps it from a 5.

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 tool takes zero parameters, so the baseline is 4 and there is nothing for the description to disambiguate. No parameter meaning is lost.

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+resource: independent leaderboards of remote MCP servers in the Official MCP Registry, and enumerates the exact categories returned (reliability, tool-definition changes, flagged servers, sign-in counts). It does not differentiate itself from close siblings like checks_top or mcp_server, so it falls short of a 5.

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?

There is no when-to-use guidance, no prerequisites, and no named alternative. The closest sibling checks_top is not referenced, so an agent cannot infer from the description alone why it should pick mcp_top over checks_top.

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