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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds real context beyond them: chronological ordering, Roblox UTC day boundaries, the returned dataset shape, and the caveat that Robux/payers are only reported for non-guest traffic. It does not contradict any annotation. It could still say more about limits on history depth or missing days.

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?

Dense but front-loaded: the core action comes first, then a compact metric glossary, then the return shape. The glossary is long but each entry earns its place because the enum is otherwise opaque. Minor verbosity in the run-on parenthetical structure.

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?

With no output schema, the description carries the burden and does describe the return shape (day plus value, rates as fractions) and data-availability caveats. Missing pieces are minor: what a 'connected game' requires, error behavior for a bad game identifier, and whether gaps/zero days appear.

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 67%, and the description compensates well by defining all eleven metric enum values (dau, playu as playtime per daily user, d1/d7/d30 retention, payers as share who pay, revenue in Robux/day, etc.), which the schema's bare enum does not explain. It also explains that the returned day is formatted like 20261021 and rates are fractions. The 'game' parameter (name or universe id) and 'days' range are only covered in the 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-and-resource: fetch one analytics metric for a connected game, returned day by day. The metric glossary makes the scope unambiguous. It doesn't explicitly say how it differs from nearby siblings like my_game_numbers or series, so an agent must infer which one gives the time series.

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?

Usage is implied by 'day by day (oldest first)' and by 'one of a connected game's own numbers', which suggests this is the per-day series tool. But there is no explicit when-to-use, when-not-to-use, or named alternative among the many siblings (my_game_numbers, series, days, trends).

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