visitors_over_time

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

With no annotations provided, the description carries the full behavioral disclosure burden. It does well by revealing that results are in the site's own timezone and by providing a concrete JSON example showing the dimensions and metrics keys. It does not mention error cases, rate limits, or pagination, but for a simple read-only reporting tool the returned structure and timezone behavior are the most important behavioral details and they are present.

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 two sentences with zero filler. It front-loads the core purpose, then provides the exact return shape in a compact JSON snippet. Every part earns its place, and the inline example is far more useful than prose describing the output.

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?

The tool is simple (two optional parameters, no output schema), and the description adequately compensates for the missing output schema by showing exactly what the response looks like. The parameter meanings are fully covered by the schema. It is missing only an explicit relationship to sibling tools, which is handled more under usage guidance, so this dimension is otherwise complete.

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?

The input schema already documents both parameters thoroughly (100% coverage), including the site_id/domain matching behavior and the period pattern/defaults. The description adds no additional parameter-level meaning beyond what the schema provides, so the baseline of 3 is appropriate.

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 clearly states that the tool returns a daily visitors and pageviews time series for a site, and even specifies the site's timezone and the exact output shape. It does not explicitly use a verb like 'retrieves' or 'returns' at the start, and it does not name a sibling tool to distinguish itself from, so it falls just 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?

There is no guidance about when to use this tool versus alternatives such as query_stats, current_visitors, or top_pages. The description implies this is the time-series reporting tool, but it never states when it should be preferred or when another sibling should be chosen instead.

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