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

Annotations already disclose that this is not read-only, not idempotent, and not destructive. The description adds useful behavioral context by saying it 'Records today's observation,' clarifying that the call has a write side effect and returns live rank plus stored daily history.

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?

Two compact sentences, no filler. The core result is front-loaded, followed by the recording side effect.

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 two-parameter tool with no output schema and annotations covering safety hints, the description broadly explains the return (live rank plus stored history). However, it omits collection semantics and does not detail the history format or how repeated calls affect stored observations.

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 only 50%: application_id has a basic description, while collection has only enum values. The description implies an application scope but does not explain the free/paid/grossing collection parameter or its default/effect.

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 states a specific resource and scope: an application's position in its own category chart, plus stored daily history. It distinguishes this from generic top-chart tools by emphasizing 'one of your applications,' though it does not name a sibling explicitly.

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?

It gives no explicit when-to-use guidance or alternatives. A reader can infer this is for checking a tracked app's category rank rather than broader top_charts, but the description does not route between siblings such as top_charts, list_top_chart_categories, or get_app_score_history.

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