DAU / WAU / MAU

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

Annotations declare readOnlyHint=true and openWorldHint=true, so the agent knows this is a safe external read. The description adds the estimation nature ("estimates") and scope (date range, multiple apps), but lacks details on rate limits, data freshness, or what the output contains. With annotations covering safety, a 3 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 single sentence is concise and front-loaded with the core purpose. It could be slightly more informative without being verbose, but it wastes no words.

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?

Given 10 parameters, two annotations, and no output schema, the description is too sparse. It omits important context such as available time_period granularity (day/week/month), country filtering, and output format considerations, which are crucial for correct invocation.

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 90%, with rich parameter descriptions including enums, defaults, and usage hints (e.g., batching, dry_run, format). The description adds nothing beyond the schema, so baseline 3 is correct when the schema does the heavy lifting.

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 a specific resource (active-user estimates) and scope (one or more apps over a date range). It does not explicitly differentiate from siblings like sensortower_app_estimates or sensortower_app_retention, but the resource is distinct enough that an agent can identify its purpose.

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?

No when-to-use guidance, prerequisites, or alternative tools are mentioned. The description does not explain when to choose this tool over other app-level metric tools such as sensortower_app_estimates or sensortower_app_retention.

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