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

Annotations only declare readOnly/openWorld/destructive=false; the description adds substantively new behavior: summary-only for every rights basis, full text never served, posts always empty, and returned fields (rights_basis, source_url, provenance SHA256). It also cites the policy basis for that constraint, so an agent knows it is a permanent rule rather than a per-request option.

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 tight sentences, front-loading the resource and then the binding constraint. Some phrasing is terse to the point of awkwardness ("the site own summary", the dated owner ruling), but every sentence carries real information and nothing is padded.

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 a read-only tool that has an output schema, the description needn't enumerate return values, yet it still names the salient fields and the summary-only guarantee. The one real hole is pagination behavior for limit/offset, which the description leaves entirely unaddressed.

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 only 33%, so the description should compensate, and it does not. It adds nothing about limit (default 10, max 50) or offset (default 0)—and given that posts is always empty, it is genuinely unclear what these paginate over, which is exactly the ambiguity the description should have resolved.

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: "Read a story thread: topic metadata plus the site own summary." That is far more precise than the name alone. It doesn't explicitly name a sibling it is not (e.g., search_news, which the schema ties to topic_id), so differentiation is only implicit.

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 the read-after-search flow via "topic metadata" and the schema pins topic_id to search_news, but the description itself never states when to use this versus search_news or a posts-listing alternative. The strong exclusion—"post full text is never served; posts is always empty"—usefully rules out a misuse case, but there is no positive when-to-use guidance.

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