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

Annotations only declare readOnlyHint/openWorldHint; the description adds meaningful context beyond that — provenance of each number, the total-vs-steam_only scope distinction, and the failure behavior (games without a legit count return the reason). It does not mention freshness/latency or caching, which would round it out.

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?

Front-loaded with sources and scope, then behavioral rules. Dense and nearly waste-free, though the source list is packed into one long opening sentence rather than separated into a compact clause.

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?

No output schema exists, so the description carries the return shape itself (by, scope, as_of) and the partial-failure case. For a one-parameter read-only lookup, nothing material 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% and the single 'game' parameter is fully documented as optional with its default behavior. The description adds no extra constraint or format guidance for that parameter, so this is the baseline for a fully documented schema.

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+resource (live player counts) and immediately names the exact upstream sources (Epic Fortnite Data API, Jagex, Steam Web API) plus the fields returned. An agent knows exactly what this returns and what it does not (no total for Steam).

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 clear operating rules: only official public sources, always cite source and scope, never estimate. It doesn't name any alternative tool, but none of the siblings (create_post, list_games, get_game_filters) overlap, so no routing guidance is really needed.

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