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

Annotations already declare readOnlyHint=true and destructiveHint=false, so no safety contradiction exists. The description adds meaningful context by defining 'active' as within the last 5 minutes, but it does not disclose response shape or any rate-limit behavior; given the read-only annotations, this is an acceptable but not rich disclosure.

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 well-structured sentence communicates the operation and the exact recency criterion. No filler or redundant restatement of the name or 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?

For a low-complexity read-only count tool with a complete input schema and an output schema present, the description supplies everything needed to understand what is being returned and how 'active' is defined. No critical context appears missing.

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%, with domain and websiteId already documented clearly. The description adds no additional parameter semantics; the baseline of 3 applies because the schema carries the full explanatory burden.

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 uses a specific verb ('Get'), a clear resource ('number of currently active visitors'), and adds a precise definition of 'active' as within the last 5 minutes. It is easily distinguished from sibling analytics tools like get_timeseries or get_breakdown.

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?

The description implies the appropriate use case: obtaining a real-time active-visitor count, with the 5-minute window clarifying the recency concept. However, it does not explicitly contrast this with alternatives such as get_timeseries or get_overview, so an agent must infer when this tool is preferable.

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