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

Annotations already declare idempotentHint=true and destructiveHint=false, and the description reinforces this with the concrete consequence that a repeat call adds nothing. It also adds two facts the annotations don't carry: an auth key is required, and get_me is the eligibility probe. It stops short of describing error behavior on a failed/unauthenticated claim, so it is strong rather than exhaustive.

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 clauses, zero filler: the action, the frequency constraint, and the status-check pointer. The most important constraint (once per UTC day) is front-loaded in the first sentence.

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?

For a zero-parameter tool with no output schema, the description covers what the call does, its once-daily limit, the auth requirement, and how to check eligibility. It doesn't say what happens on a failed or unauthenticated claim, which is a minor residual gap.

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. The only input-adjacent detail in the description is 'Needs a key,' which reads as an auth credential rather than a schema parameter, and no parameter semantics are needed beyond that.

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 ('Claims the daily Luck Points bonus') and scopes it to a once-per-UTC-day action. It also routes to the sibling get_me for status, so an agent can distinguish it from the other claim/publish tools without opening any 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?

Gives explicit when-to-call (once per UTC day), an explicit when-not (calling again the same day adds nothing), and names the alternative for checking eligibility ('get_me shows whether today's is still open'). Nothing about invocation timing is left to inference.

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