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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered; the description earns credit by adding an authorization scoping rule (only games my_games reports as theirs) that the annotations cannot express. It also discloses a conditional data gap — pay-share and Robux metrics are omitted for guest-only games — which is genuinely useful behavioral context.

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 scope statement is front-loaded, but the body is a single run-on sentence with a long comma-spliced metric inventory and nested parentheticals, which makes it hard to scan. It is information-dense but not well structured.

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 of telling the agent what comes back, and it does so thoroughly — metric names, averaging windows, benchmark comparisons, and conditional fields. It omits any note on response shape or size, which is the only material gap for a read-only fetch tool.

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% and the single parameter already documents that it accepts a name or universe id obtainable from my_games. The description repeats that fact rather than adding new constraint or format detail, so the baseline 3 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?

Opens with a specific verb+resource framing ("One of the person's connected games, from Roblox's own analytics") and enumerates the metric families returned, so an agent knows this is per-game analytics rather than a list. It doesn't distinguish itself from the obvious siblings my_game_days and my_game_sources, which likely return overlapping slices of the same data.

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?

The precondition "Private: only games my_games says are theirs to read" and the pointer to my_games for identifiers imply the call flow, but there is no explicit when-to-use versus my_game_days, my_game_sources, compare, or charts. Usage is inferable rather than stated.

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