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

The readOnlyHint already signals a safe read, and the description adds real context: the scope is limited to live apps, the window is fixed at 7 days, the output shape is two plain sentences per app, and ads appear only when they ran. It does not mention volume limits or what happens with many apps, but the behavioral picture is otherwise solid for a no-parameter report.

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?

One sentence opens with the scope ("Every live app's last 7 days") and then specifies the contents, closing with the routing hint. Every clause carries information, and nothing is padding.

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 input parameters, no output schema, and only a readOnlyHint, the description carries the burden well by describing the return content and its per-app, two-sentence format. The only gap is that it does not say how many apps or how large the response can get, which matters for a fleet-wide report.

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 tool takes zero parameters and the schema is empty at 100% coverage, so there is nothing to misread. The description correctly implies there is nothing to filter or configure (fixed 7-day window, all live apps), which is exactly the semantics an agent needs for a parameterless call.

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 names a specific resource (every live app) and time window (last 7 days) and enumerates the exact contents of the report: downloads, sales/money, people/retention, and ads. It does not name a sibling tool for contrast, so it falls short of the 5 tier, but an agent can still tell it apart from list_apps or ad_campaigns because those names imply narrower answers.

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?

"Use first for a general 'how is it going'" is an explicit rule for when to reach for this tool and implies it is the entry point before deeper drill-downs. It stops short of naming the alternatives (app_story, why_did_it_change, ad_campaigns) or stating when not to use it, so it is clear context without exclusions.

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