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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and a closed-world scope, so the safety profile is fully covered. The description adds only that setting `previous`=1 extends the read to the preceding period; it says nothing about row ordering, pagination, or what metrics accompany each dimension value.

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 short sentences, with the core purpose front-loaded and the comparison behavior second. Slightly redundant with the schema's own `previous` description, but nothing is padded or buried.

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 an 11-parameter analytics tool with no output schema, the description leaves a meaningful gap: it never says which metrics (visitors, revenue, conversions) accompany each dimension row, nor how comparison results are shaped. The safety and parameter sides are well covered by annotations and the schema, but the return-value side is not.

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 every parameter including `previous`, `dim`, `period`, and `filters` is already documented in structured form. The description's mention of `previous` set to 1 merely restates the schema text and adds no new meaning such as how comparison rows are labeled or what extra fields appear.

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 states a concrete resource — the top values of a chosen dimension — and lists example dimensions (channel, referrer, campaign, page, country, device), so an agent knows what comes back. It never names the closely related sibling get_breakdown, so the differentiating feature (comparison against a prior period) is only implied via the `previous` parameter note.

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?

There is no explicit when-to-use guidance and no exclusions. With a sibling literally named get_breakdown, the agent must infer from the parameter note alone that this is the comparison variant; the description should say 'use get_breakdown for a single period' but does not.

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