Yandex Metrika: catalog

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavior: it performs no API call, and it warns that metric entries carry aggregation rules such as 'users must never be summed' — a real correctness constraint an agent would otherwise miss.

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?

A single dense sentence, front-loaded with the verb and resource, with the kind enumeration and the critical aggregation caveat inline. No filler and nothing redundant with the schema.

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?

An output schema exists, so the description need not describe return values, and both parameters are fully documented in the schema. For a two-parameter read-only catalog tool, nothing an agent needs in order to call it correctly is absent.

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 100%, so baseline would be 3, but the description goes beyond the bare enum by explaining what each kind contains (presets = ready-made reports; metrics = unit and aggregation rules; dimensions; periods). It does not describe the optional 'search' substring filter, though the schema documents it adequately.

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 ('Lists the Yandex Metrika report fields this server supports') and enumerates the exact four kinds. It is instantly distinguishable from the sibling report-execution tools (metrika_run_report, metrika_run_timeseries), which consume rather than list these fields.

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?

Usage is clear by implication and reinforced by 'No API call', signalling this is a cheap discovery step to take before calling a report tool. What is missing is an explicit 'call this first if you do not know valid metric/dimension names' routing sentence against the siblings.

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