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

Annotations already establish readOnly/openWorld/non-destructive, so the safety profile is covered. The description adds real behavioral detail beyond them: which metric the window governs (follower growth) versus the fixed 90-day lookback for video counts, and that transcript presence is reported per video. It says nothing about behavior for unknown profile_id, empty windows, or rate limits, which is why it is not higher.

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 the resource and its metric inventory, and closed with the differentiator that matters most for routing. No filler, no repetition of the tool name or title.

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 carries the burden of describing the return contents, and it does so reasonably well by listing the metric families. However, the sole required parameter (profile_id) is left undefined in both schema and description, and the metric list is dense enough that the agent must infer the response shape rather than know it.

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 50%: window_days is already documented in the schema with its default of 30, and profile_id has no description anywhere. The description does add one useful clarification the schema lacks — that the window applies to follower growth specifically, while the 90-day video metric is fixed — but it never explains what profile_id must reference, which is the bigger gap.

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 names the resource ('Метрики автора') and enumerates the specific metrics returned: followers and their growth over a window, reach norm for the account size, medians, 90-day video count, and corpus/transcript coverage. It does not name the adjacent siblings (author_report_get, author_dossier_get), but the exclusivity claim that follower growth lives ONLY here gives the agent a concrete way to tell it apart from those tools.

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?

'Прирост подписчиков есть ТОЛЬКО здесь' implies when to reach for this tool — whenever follower growth is needed — but the guidance is one-directional. There is no explicit when-not statement, no mention of author_report_get or author_dossier_get as alternatives for the other metrics, and no stated prerequisites.

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