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

No annotations are provided, so the description carries the full behavioral burden, and it discloses nothing: not whether this is a read or write, not what the response contains, not how activity is aggregated. With no output schema and no annotations, the agent has zero behavioral context beyond the name.

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?

A single five-word phrase with no waste and a front-loaded subject, so it is not verbose. However, it is terse to the point of under-specification rather than deliberately concise – brevity here forfeits meaning.

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 tool with no annotations, no output schema, and an unexplained grouping term, the description should define what 'band' means and what the result looks like. It leaves the central concept of the tool undefined, so an agent cannot reliably interpret results.

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% and both parameters are enums with explicit meanings ('Game server region', 'How far back an account counts as active'), so the schema does the heavy lifting. The description adds nothing about parameters, which is acceptable given full coverage, but 'by band' leaves the aggregation dimension (the thing that might relate to window) unexplained.

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 is a near-restatement of the tool name ('players_activity' → 'Player activity by band') with no verb and no clear resource scope. 'By band' is undefined jargon – an agent cannot tell whether it means tier bands, rating bands, or regions, nor how this differs from siblings like players_distribution or players_winrate_by_tier.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives despite a large sibling set covering player statistics. The only usage signal is the required region parameter, which comes from the schema, not the description.

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