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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered structurally. The description adds behavioral context about what the sort metric actually measures, including a data-backed claim (39% of raw comment count explained by views), which is genuine value beyond annotations. It says nothing about whether an author with no reels errors or returns empty, or about how the result set is bounded beyond the schema's limit of 50.

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 sentences, front-loaded with what the tool returns before moving to sort semantics. The second sentence is dense and carries a statistic, but every clause supports the comment_rate-vs-comments decision. No filler or restatement of the name.

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 no output schema, the description must cover return values, and 'числами и долей комментариев' is only a partial sketch of what fields come back. The key risk — confusing comment_rate with comments — is fully addressed, so an agent can call it correctly, but the shape of the response and the meaning of the other sort modes (breakout, recent) are left to the enum names.

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 75%, below the threshold where the schema alone would justify a baseline 3. The description compensates by explaining the semantics of the comment_rate enum value relative to the comments enum value — a distinction the schema only lists, never explains. It still adds nothing about days, limit or profile_id, but the enum clarification is the parameter most likely to be misused, so it earns above baseline.

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 concrete resource and output shape: an author's reels with numeric metrics and a comment share ('Ролики автора с числами и долей комментариев'). That is specific enough to separate it from the account/author_stats siblings, which return aggregate profiles rather than per-reel rows. It stops short of naming a sibling alternative explicitly, so it is clear but not maximally differentiated.

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 gives real guidance on choosing between two sort modes, explaining that comment_rate surfaces 'what people went to WRITE under' while raw comments largely mirrors views. It offers no guidance on when to pick this tool over author_stats, author_report_get or analysis_get, nor on choosing days/limit. Usage is implied by the sort discussion rather than scoped at the tool level.

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