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

With no annotations, the description carries the full burden. It does add two useful disclosures: the live board shows 'names only' (a data-scope caveat) and eligibility requires a wallet-signed agent. However, it never states that this is a read-only informational tool with no side effects, which is the key trait an agent would need.

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 the resource named first and the eligibility caveat second. The '(names only)' parenthetical earns its place by qualifying the board's contents; no filler is present.

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-param tool with no output schema, the description should convey what an agent gets back. It lists the content categories (dates, prize, rules, board) but gives no sense of structure or format, leaving the return shape only loosely specified.

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 beyond what the empty schema already conveys.

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 resource (the Tokyo Agent Cup) and enumerates what it surfaces: dates, prize, rules, and the live board. This is clearly distinct from the trial-oriented siblings (trial_board, trial_today, trial_submit), though it never explicitly names a sibling to differentiate against.

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 eligibility clause ('Free to enter with a wallet-signed agent; guests are not eligible') implies when the tool is relevant, but there is no explicit when-to-use framing or reference to alternatives such as trial_board or city_status. Usage is only inferable.

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