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

With no annotations provided, the description carries the full behavioral burden, and it discloses nothing: no read-only nature, no auth requirements, no indication of what the returned Marks of Excellence figures represent or how they are scoped per region/tank. Four words cannot cover a data-retrieval contract.

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 description is a four-word fragment that is under-specified rather than concise; brevity here comes at the cost of all useful information. There is no front-loaded statement of what the tool actually returns.

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 lookup with no output schema and no annotations, the description should at minimum state what the Marks of Excellence payload contains and how the region affects it. The schema covers the inputs, but the return contract and behavior remain completely unexplained.

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%, with 'slug' and the three-value 'region' enum fully documented in the schema itself. The description adds no parameter meaning beyond that, so the baseline 3 for high coverage 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 'Tank Marks of Excellence' essentially restates the tool name and provides no verb or framing. An agent can guess the resource is Marks of Excellence data for a tank, but it learns nothing about what kind of data (percentile thresholds, distribution, player counts) is returned. It also does not distinguish this from the near-identical sibling tanks_by_slug_marks_of_mastery.

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 guidance on when to call this tool, what prerequisites exist, or how it differs from alternatives such as tanks_by_slug_marks_of_mastery or the aggregate tanks_marks_of_excellence. The agent must infer usage entirely from the name.

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