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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that it returns a list and hints at pagination ('use page/pageSize when paginated'), which provides some behavioral context beyond the annotations, but does not elaborate on response structure. No contradiction.

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 sentences with no filler. The core action and feed types are front-loaded, and the pagination note is placed logically. Every sentence 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?

For a tool with no output schema, the description is thin on return value details. It says 'Returns a list' and hints at pagination, but does not describe item fields or the pagination contract (e.g., hasMore/nextPage) that the schema's page description references. The open-world annotation suggests variability, but the description does not clarify what a consumer should do with the returned items. It is minimally adequate given the schema's pagination hints, but leaves room for improvement.

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 input schema fully documents all four parameters with descriptions (feed enum, page, limit, pageSize). The description does not add additional semantic meaning beyond the schema; it only repeats the existence of pagination. Baseline 3 applies because schema coverage is 100%.

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?

The description clearly states the verb 'List' and the resource 'Hacker News feed', and enumerates the exact feed types (top, new, best, ask, show, jobs). This distinguishes it from sibling search or item-specific tools like hackernews_search_list or hackernews_story_get, even without explicit comparison.

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?

The description gives no guidance on when to use this tool versus alternatives such as hackernews_search_list, hackernews_story_get, or other listing tools. It does not mention exclusions or preferred contexts, leaving the agent to infer when browsing feed categories is appropriate.

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