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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered. The description still adds genuinely new behavior: paid access at $0.01 USDC per successful call via x402 on Solana, plus an HTTPS fallback endpoint — details an agent cannot get from 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?

Two dense but purposeful sentences: capability and filters first, return payload second, cost and alternate endpoint last. No filler, and the most decision-relevant information (what it searches) leads.

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 10-parameter tool with no output schema, the description usefully lists returned fields (title, URL, points, comments, author, time, comment text, HN links) and discloses cost. Minor gaps remain around pagination limits and how `exact` interacts with sort, but the agent has enough to invoke it correctly.

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 the schema already documents all ten parameters including defaults and enums. The description restates the main filters (sort, date range, type, author, minPoints) without adding syntax or edge-case detail, and it omits page/limit/exact entirely — 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 and resource ('Search Hacker News stories and comments') and pins the backing index (Algolia HN). No sibling tool targets Hacker News, and the naming plus scope make the boundary against arxiv_search/pubmed_search/reddit-like siblings obvious.

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 enumerates available modes (relevance vs newest-first, date range, type filter, author, min points), which implies how to narrow a query, but it never states when to choose this tool over an alternative or any prerequisite/exclusion. Usage is inferable rather than directed.

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