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

Annotations already declare readOnly/openWorld/idempotent/non-destructive behavior, so the bar is lower. The description adds valuable context beyond the annotations: no auth required, Algolia as the backend, CC BY 3.0 data license, and the return field set. It does not contradict annotations and provides useful operational context.

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?

Four sentences with no filler; core purpose is front-loaded in the first sentence. The content-type enumeration appears twice ('covers... Ask HN threads, Show HN posts...' and 'Supports filtering by type...'), a small redundancy, but each sentence otherwise earns its place.

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 need not explain return structure. It covers scope, ranking, filtering, auth, and data provenance. The only notable gap is the omission of 'comment' from the described type filter, which the schema corrects. For a read-only search tool, the definition is complete enough for correct invocation.

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 four parameters. The description adds marginal value by mentioning type filtering and result fields, but it actually omits the 'comment' type that the schema enum includes, which is a minor inconsistency. Since the schema carries the semantic load, a 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?

The description states a specific verb ('full-text search'), a specific resource ('entire HackerNews history'), and a clear ranking criterion ('ranked by relevance'). This directly distinguishes it from sibling tools like hnalgolia.search.recent (chronological) and hnalgolia.search.comments (comment-focused). The content type coverage and return fields further pin down exactly what it does.

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 implies when to use it: when you want relevance-ranked full-text search across all HN history. However, it never explicitly names alternatives or states when-not-to-use (e.g., 'for recent items use hnalgolia.search.recent'). The context is clear but the exclusion guidance is left to inference.

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