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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so the safety profile is covered. The description adds real behavioral context beyond that: nulls carry a reason and daysMissing, every record has asOf/source/grade, and estimates are explicitly not measured sales. Most of this, however, restates the return shape that the output schema already defines.

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 in a single sentence, but that sentence is a dense run-on with nested parentheses, and the grade definition plus the revenue-estimate caveat are stacked inline rather than separated. It is information-dense but harder to parse than a short purpose statement followed by structured notes.

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?

Given an output schema and fully documented parameters, the description adequately covers data provenance, nullability semantics and estimation caveats. Its remaining gap is competitive positioning against the many sibling tools, which is not addressed at all.

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 the game parameter documenting id formats, title matching and tie-breaking, and platform enumerating accepted values. The description adds nothing about either parameter — platform is not mentioned at all — so this sits at the baseline the schema earns on its own.

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 concrete resource and scope: the trajectory of one game benchmarked against the medians of its up-to-3 largest niches, with specific metrics (24h growth, momentum, D7/D30 retention). It is specific enough for an agent to know what comes back, but it never contrasts itself with close siblings such as get_game, get_game_history or analyze_niche.

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 explicit when-to-use guidance, no when-not-to-use condition, and no named alternative among the twelve siblings. The only routing signal is implicit in the word 'trajectory', leaving the agent to infer that this is the single-game benchmarking call versus the niche-level or history calls.

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