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

No annotations, so the description carries the burden. It usefully discloses the paid cost model ($0.05 USDC on Base via x402) and the 'hot' ranking heuristic, which are real behavioral facts. It does not cover rate limits, what the response contains, or how 'new' is determined relative to the last call.

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?

Pricing and core purpose are front-loaded in the first sentence, with use cases packed into the second. Dense and mostly non-redundant, though the use-case list runs slightly long.

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 no annotations and no output schema, the description supplies the essentials an agent needs: cost, what it detects, and when to invoke it. The main remaining gap is the meaning/format of 'target'.

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 single 'target' parameter has 0% schema description coverage, so the description must compensate. Its examples ('did X get posted on HN', 'about a product', 'tracking new threads') imply target is a keyword/product/entity, but never define accepted formats (handle, domain, keyword, URL).

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 capability: change detection over mention history, surfacing new HN discussions and flagging hot ones by points/comments. The 'vs history' framing hints at how it differs from siblings like mention_snapshot, though no sibling is named explicitly.

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 concrete triggering scenarios: 'did X get posted on HN', discussion monitoring, launch buzz alerts, tracking new threads. Clear context for when to reach for it, but no explicit when-not or named alternative tools.

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