Yandex Metrika: time series

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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description still adds non-obvious behavior: exact calendar boundaries in the counter time zone, flags on buckets containing today or clipped by the period, top-N segment series when dimensions are supplied, and quota consumption despite the read-only nature.

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?

Five dense sentences, front-loaded with what the tool produces, then boundaries, then the quota warning. Every sentence carries information; the only cost is that the prompt-injection caveat sits mid-paragraph rather than at the end.

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 12-parameter, nested-schema tool with a full output schema, the description covers the remaining gaps: time-zone semantics, boundary clipping, cache/quota behavior and untrusted result labels. An agent can call this correctly without further context.

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% and the parameters are richly documented, so the baseline of 3 applies. The description adds the bucket/dimension interaction ('Optional dimensions return top-N segment series'), but it also states a default of 'last 28 complete days by day' while the period schema declares 'last_7_complete_days' — an inconsistency the agent must resolve from the schema.

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 opens with a specific verb and resource ('Shows Yandex Metrika metric dynamics') and immediately narrows scope to bucketed time series (day/week/month). That distinguishes it from a plain report tool, though it never names metrika_run_report or metrika_compare_periods as the contrasting siblings.

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?

It gives a usable default ('last 28 complete days by day'), a rule for weekly series, and a caution against looping calls, which is real guidance. What is missing is explicit routing: nothing says when to pick this over metrika_run_report or metrika_compare_periods.

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