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

Annotations already declare read-only, idempotent and open-world behavior, and the description adds substantial context beyond them: the exact return fields delivered, the default type/sort behavior, and the paid x402 USDC-on-Base model with $0.001 per successful call and the PaymentRequired object on unpaid calls. That payment and output-shape detail is real value not available in the 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?

Front-loaded with the core purpose and scope, then returns, then the alternative service, then payment. Dense but every sentence carries useful information; only slight trimming would be possible without losing content.

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 output schema, the description explicitly lists the returned fields, covers default behavior and the payment requirement, and its annotations cover the safety profile. Nothing an agent needs to call this search tool correctly is missing.

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 coverage is 100%, so all six parameters and their defaults are already documented in the schema; the description's mentions of 'stories or comments', 'last N days', 'minimum points' and 'relevance or newest' merely restate those schema semantics. It adds no format, range or interaction detail beyond what the schema provides, so the baseline 3 applies.

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 (searches) and resource (HN stories/comments across history), plus default behavior (story, relevance sort) that disambiguates it from a live-feed fetch. It does not explicitly name the sibling hn_thread, so the differentiation from that sibling is inferable but not stated.

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 a clear use case (find what HN says about a product, company, library or topic) and an explicit exclusion with an alternative (use ScrapeMole Pulse for live front page/new/best/Ask HN/Show HN/jobs). However, it does not address when to prefer hn_thread over this search within the same server.

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