Read Metrika: counters, goals, statistics

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

Beyond the readOnly/idempotent annotations, the description discloses non-obvious behavioral traps: accuracy=full is forced because the service default is SAMPLING, data lags about 2 hours and the current day is underfilled, and the tool needs its own Metrika credential rather than the Direct one. This is exactly the context annotations cannot convey.

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 front-loaded and each section earns its place with practical warnings. It is slightly redundant with the schema's date2 and action descriptions, but the critical caveats justify most of the length.

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 three-action API with 8 parameters and no output schema, the description provides the essential surrounding context: authentication, read-only scope, sampling behavior, data lag, and the write alternative. Combined with the detailed schema, an agent has enough to select the right action and call it correctly.

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 baseline is 3. The main description mostly restates what the schema already says, such as action meanings, ym:* names passed through as written, and the date window advice. The accuracy=full detail is valuable but functions more as behavioral context than a parameter-semantics addition.

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 title and first sentence define the tool as 'The Yandex Metrika API, reading only' with three explicit actions. It clearly distinguishes the read scope from the write sibling direct_metrika_goals, so an agent can tell this tool apart immediately.

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 concrete per-action guidance, warns to end date windows yesterday because of the 2-hour data lag, and explicitly says creating goals is a write that belongs in direct_metrika_goals. It also explains the separate credential requirement, leaving little ambiguity about when and how to use the tool.

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