Get Steam charts

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

Annotations only cover read-only/open-world, but the description adds real behavioral context: results are cached for a few minutes, all charts are global (identical in every country), no API key is required, names from a best-effort lookup may be null, and last_week_rank being null signals a new entry. These are traits no annotation or schema conveys.

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?

Purpose and routing come first, with behavioral caveats trailing. Packed but efficient; most sentences carry distinct information, though a few clauses (the return-field enumeration) crowd the middle.

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?

Output schema exists, yet the description still clarifies the returned field subset and where to go for price/review data (get_items), plus nullability and caching. Nothing an agent needs to call this correctly is missing.

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 100%, so the enum and limit are already documented, but the description adds meaning beyond the schema -- what each chart actually ranks (weeks on chart, peak players on the last full day, live players now), the 100-entry cap nature, and the null semantics of chart metrics.

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?

States a specific verb and resource ('Get what is popular on Steam right now as a ranked list') and enumerates the three chart modes with their distinct meanings. It explicitly distinguishes itself from get_current_players, get_featured, and discover_games, so an agent can select it without opening sibling schemas.

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?

Gives the triggering intent ('what's hot / top selling / most played') and then names three alternatives with the exact condition that selects each: per-game live count, storefront curated sections, and filtered catalog search. Both when-to-use and when-not-to-use are explicit.

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