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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered; the description goes beyond that with the payment model ($0.002 per successful call via x402 on Base/Solana/Arc, failed calls free), the fact that no API key is needed, and the result set restriction to stories. It does not cover pagination or result-count behavior beyond the limit param.

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?

Three tight sentences: what it searches, what comes back, then cost. The API provenance and no-key detail are front-loaded, and no sentence is filler.

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 an output schema present, the description needn't explain return shape, and it correctly focuses on source, scope, ordering, and billing. The one gap is sibling differentiation against `search_hackernews_items`, which matters in a list this dense.

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 `q` and `limit` are already fully documented with types and ranges, establishing the baseline 3. The description adds nothing about query syntax, matching behavior, or why `limit` is typed as a string, so it does not exceed what the schema provides.

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+resource (Hacker News story search) plus the backing API and the returned fields, so an agent knows exactly what this pulls. It does not differentiate from the sibling `search_hackernews_items`, which sounds like it covers the same source, leaving ambiguity about which to pick.

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?

Usage context is implied only: 'Returns stories only' and 'most relevant first' hint at scope and ordering, and the pricing note implies a pay-per-call cost model to weigh. There is no explicit when-to-use or when-not-to-use guidance, and no routing versus the near-identical Hacker News sibling.

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