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

No annotations are provided, so the description carries the full burden, and it discloses only that the call costs 1 credit — genuinely useful context. It says nothing about return format, pagination, what happens with insufficient credits, or whether results are cached/live.

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?

A single front-loaded line with purpose first and the enum clarification and cost trailing; nothing is wasted. It is terse to the point of being cryptic for non-Chinese-reading agents, but structurally sound.

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 3-parameter tool with no annotations, no output schema and 0% schema coverage, the description does too little: two of three params are unexplained and return behavior is unknown. Only the credit cost and hosting enum are covered.

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 0% schema coverage, the description compensates for one of three parameters by explaining the hosting enum meanings (free = hosted subdomain, custom = own domain). It leaves limit and min_points entirely undocumented in both schema and description, so the gain is only partial.

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 resource and action: discovering new sites on HN, with the 'latest' name implying recency. It is clear enough on its own, though it doesn't explicitly say it returns the most recent new sites or how they're ranked.

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?

No indication of when to use this versus alternatives (e.g., domain_timeline or trends_rising) and no prerequisites. The parenthetical describes enum values, which is parameter help, not usage guidance.

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