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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful context the annotations don't carry: results are in the site's timezone, and omitting the window returns only the history the plan retains — a retention caveat 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?

Two sentences, no filler, front-loaded with the resource and payload, followed immediately by the windowing contract. Every clause carries information an agent needs.

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 correctly enumerates what a row of the series contains and notes the timezone, so an agent knows what it gets back. Only the shape/ordering and volume of the series is left implicit, which is a minor gap for a read-only tool.

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%, with 'days' and 'site' undocumented in the schema. The description compensates by explaining the days-vs-from/to windowing contract and the omit-both behavior, which is exactly the undocumented part of the schema. 'site' is self-evident from context.

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 resource (daily traffic series for a site) and enumerates the exact metrics returned (visits, visitors, pageviews, clicks, bots per day), which meaningfully separates it from siblings like get_stats, get_breakdown and get_realtime. It never names which sibling to prefer, so it falls short of a 5.

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?

Gives real guidance on how to scope the query (use days, or from/to, omit both for full retained history), but frames it entirely around parameters rather than when to choose this tool over get_stats or get_breakdown. Usage is implied by the metric list rather than stated.

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