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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered. The description adds genuinely new behavioral context: only games with Roblox analytics connected expose private numbers, and it flags per-game whether Robux are readable — permission-scoping facts the annotations cannot convey. It stops short of describing result size or behavior when the user has no games.

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?

Two sentences, front-loaded with scope before the sibling routing, and no filler. The first sentence is dense with nested parentheticals ('claimed here, or on their Roblox account or its groups'), which slows parsing slightly, but every clause carries scope information that matters.

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 and no parameters, the description carries the return-shape burden and does so: universe id, name, current players, role, analytics-connected flag, and Robux readability are all listed. Combined with the explicit entry-point guidance, an agent has everything needed to call it correctly.

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?

The tool takes zero parameters, so the baseline is 4; there is nothing for the description to disambiguate. It correctly adds no parameter talk and instead spends its words on scope, which is the right allocation for a no-arg tool.

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 specific resource (the signed-in person's games) and enumerates exactly which games qualify — owned/claimed, seat-held, or studio-team-accessible — plus the per-game fields returned. This is far more specific than the bare name 'my_games' and lets an agent distinguish it from siblings like game, search, or find without opening the schema.

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?

It explicitly says 'Start here before my_game_numbers, my_game_days or my_game_sources,' naming three sibling tools and the ordering relationship among them. That is an explicit when-to-use-this-first directive plus the alternatives it precedes.

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