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

Annotations already establish read-only, idempotent, and non-destructive behavior. The description goes beyond annotations by stating 'No auth required' and listing the returned fields (title, URL, author, score, comment count), plus data licensing. It adds relevant context without contradicting the annotations.

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?

The description is concise, front-loaded with the core purpose, and each sentence adds value (purpose, output fields, filtering, auth, licensing). It avoids fluff and is well-structured, though slightly longer than necessary due to the licensing note, which is still relevant.

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 read-only search tool with a rich schema and output schema present, the description adequately covers the essential aspects: what it searches, sorting, output fields, and filtering. Pagination details are in the schema, so the description doesn't need to restate them. The only minor gap is not explaining the difference from relevance-ranked search, but the overall context is sufficient.

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 parameter descriptions in the schema already document each parameter. The tool description adds minimal extra meaning—only a brief mention of type filtering (which the schema already covers via the enum). With full schema coverage, the baseline of 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?

The description clearly states the tool performs full-text search over Hacker News history, ranked by submission date (newest first), and lists the output fields. This distinguishes it from sibling tools like hnalgolia.search.relevance (relevance-ranked) and hnalgolia.search.comments (comments-only), making the purpose unambiguous.

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?

It provides clear context for use: 'ideal for finding the latest community discussions on any topic.' However, it does not explicitly mention when not to use it or name alternatives such as hnalgolia.search.relevance for relevance-based queries, which would strengthen routing. Still, the intended use case is clear.

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