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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the bar is lower, and the description still adds real behavioral context: rank 1 is a composite-score artifact rather than an endorsement, which warns the agent against over-trusting the result. It stops short of disclosing anything about freshness or rate limits, but the caveat is genuinely useful beyond 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?

Two tight sentences with zero filler; the core behavior comes first and the routing caveat second. Every clause earns its place.

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?

An output schema exists, so return-value detail is not needed, and the description still summarizes the payload shape. Combined with a fully documented single optional parameter, the definition is nearly complete; only minor gaps (result freshness / stability of the ranking) remain.

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 description coverage is 100% and there is a single optional parameter, so the schema already explains that use_case is an optional echo field. The description adds no parameter-level meaning at all, which is acceptable here but not additive.

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 ('Return whichever solution currently holds rank 1 on 402MCP.org') plus the payload ('full breakdown, install commands and code'). It explicitly contrasts itself with the sibling recommend_payment_rail, so an agent can distinguish it without opening either 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?

Gives both the use condition (you want the current rank-1 solution) and the exclusion with a named alternative ('for a choice that fits specific requirements, call recommend_payment_rail instead'). This is explicit when/when-not routing rather than implied context.

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