Analytics realtime report

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

The annotations already declare readOnlyHint=true and destructiveHint=false, so the description is consistent with those. The description does not add any extra behavioral context (e.g., authentication, rate limits), but it also does not contradict the annotations. With the bar lowered due to annotations, a neutral score is appropriate.

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 extremely concise: two short sentences plus a list of common values. It leads with the core purpose and then provides the use case and examples, with no unnecessary words or redundancy. The structure is clean and front-loaded, making it easy to scan.

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 description covers the main purpose, a use case, and example parameter values, which is sufficient for a simple reporting tool. The output schema is present, so the description does not need to explain return structure. The only notable gap is the lack of explicit guidance on the `property_id` parameter, but this is a minor omission given the overall 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?

The schema provides no descriptions for any of the three parameters, so the description must compensate. It lists common dimensions and metrics, which gives useful examples for the `dimensions` and `metrics` parameters, but it does not explicitly map those examples to the parameters or explain the `property_id` parameter at all. The compensating information is partial, hence a mid-range score.

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 the tool's function: 'Run a GA4 realtime report showing current active users and events.' It uses a specific verb ('Run') and identifies the resource ('GA4 realtime report'). The mention of 'realtime' and 'current active users' distinguishes it from siblings like run_ga4_report, which presumably handles historical data.

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 provides a concrete use case: 'Useful for checking if tracking is firing correctly after code changes.' This gives clear guidance on when to use the tool. It does not explicitly contrast with alternatives like run_ga4_report or validate_tracking, but the realtime focus and the specific use case make the intended scenario clear enough.

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