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

Annotations already declare non-read-only, idempotent, non-destructive, open-world. The description adds real context beyond them: the output is a public page link plus a PNG, winning emails are masked, and — importantly — the tool publishes nothing itself, so an agent knows no external broadcast occurs.

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 compact sentences with zero filler: the artifact is front-loaded, the output format follows, and the non-publication caveat closes it. Every clause carries information.

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 one well-documented parameter, rich annotations, and no output schema, the description covers what an agent needs: what is produced, what is returned, and that nothing is published. It stops short of saying how the link/PNG are delivered, but that gap is minor.

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 100% and the single parameter already documents "A drawn giveaway." The description's "drawn giveaway's winners" merely echoes that constraint without adding format or selection 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?

States a specific verb and artifact — "Make a square card announcing a drawn giveaway's winners" — with the added qualifier "square" and masked emails. It does not explicitly distinguish itself from the sibling create_share_card, so an agent must infer the difference from the name alone.

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 phrase "a drawn giveaway's winners" implies the prerequisite that the giveaway must already be drawn, and "It publishes nothing itself" clarifies the boundary of the action. However, there is no explicit when-to-use guidance or routing away from create_share_card or draw_winners.

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