Fetch Hacker News

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

Annotations already declare readOnlyHint, openWorldHint and idempotentHint, so the safety and external-dependency profile is covered. The description adds only that it hits news.ycombinator.com and what fields come back, which is largely restated by the output schema; no rate limits, caching, or ordering behavior is 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?

Two tight sentences with the capability front-loaded and usage context second. Every clause carries information, though the field enumeration is slightly redundant given the output schema.

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?

With rich annotations, a 100%-covered schema and an existing output schema, the description covers source and scope adequately for an agent to invoke it correctly. Minor gaps (story ordering, freshness of 'current') are not critical for the call.

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%, so both the 'limit' range and the 'category' enum semantics are fully documented in the schema. The description contributes no additional parameter meaning, so the baseline 3 is appropriate.

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 (fetch) and resource (current stories from Hacker News) and enumerates the returned fields (title, link, score, author, comment count). An agent immediately knows exactly what this tool produces and from which source.

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 clear triggering contexts — tech news questions, developer trending topics, recent Ask HN / Show HN posts. It does not name exclusions or alternatives, but with no sibling tools there is nothing to route away from, so the guidance is sufficient.

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