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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered structurally; the description adds a genuine behavioral fact with 'Needs a key' (authentication requirement). It stops short of covering failure behavior or any rate limiting, so it adds value but not richly.

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?

Three short sentences, front-loaded with what is returned before the auth requirement and the routing alternatives. Every sentence earns its place; nothing is padded or duplicated from the schema.

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 parameters, no output schema, and annotations covering the safety profile, the description supplies what the structured fields cannot: the returned fields, the key requirement, and sibling routing. Nothing an agent needs in order to call it 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?

The tool takes zero parameters with 100% schema coverage, so the baseline is 4 and there is nothing for the description to clarify. No misleading parameter claims are made.

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 the exact resource contents returned — handle, Luck Points balance, and check-in status — so an agent knows precisely what get_me yields. It also distinguishes itself from two close siblings ('start_here gives the same plus next steps; my_plays gives your play history'), which removes ambiguity without opening either 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 states concrete triggers ('check your balance before you stake, or whether check_in is due') and explicitly routes the agent to alternatives when a different scope is wanted. The start_here and my_plays comparisons make the selection criteria unambiguous rather than implied.

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