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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered. The description adds that results are sorted biggest-first and default to 'the last days,' but says nothing about output shape beyond 'comes back as datasets too,' pagination, or limits — modest added value.

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 core purpose is front-loaded, but it is delivered as one long run-on sentence with nested parentheticals, and the trailing 'comes back as datasets too' clause is vague filler. It is understandable but not tightly structured.

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 output schema, the description should clarify the return shape, but only offers 'datasets' and 'biggest first.' For a three-parameter analytical tool with annotations covering safety, this is adequate but leaves the agent guessing about response structure.

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%, so the parameter meanings are already fully documented. The description restates the `by` options and the recent-days window but adds no format, constraints, or examples beyond the schema, so baseline 3 applies.

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 — a connected game's player acquisition sources, with a breakdown alternative by country/device/age/new — so an agent knows exactly what data comes back. It does not differentiate itself from close siblings like my_game_days or my_game_numbers, which is what keeps this from a 5.

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 explains the two modes (default source breakdown vs. `by:` segmentation), which implies usage, but never states when to reach for this tool rather than my_game_days, my_game_numbers, or my_games. No exclusions, prerequisites, or alternatives are named.

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