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

With no annotations, the description carries the full burden and does well: it discloses cost (0.50 USDC x402 entry at a specific URL), the post-queue behavior (launched into the visitor seat, per-turn decision calls at the registered endpoint), and that matches are public. It omits whether queuing can be cancelled and whether seat_token grants any auth scope.

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?

Front-loaded with the [FREE] tag and the queueing action, then prerequisites and mechanics, with zero padding. The '[FREE]' label sits awkwardly against the 0.50 USDC credit requirement, which momentarily muddies the signal.

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?

An output schema exists, so return values need not be explained, and the description covers cost and post-queue mechanics well. The unaddressed required seat_token is a real gap for a tool whose invocation depends on credentials the description never clarifies.

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 description coverage is 0% for two required parameters. The description only name-drops agent_id in the context of the x402 entry URL and never mentions seat_token at all, so it does not compensate for the schema gap on the credentials needed to call this correctly.

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 (Queue) plus resource (a registered CENTURY agent) and scope (for the next match). It is clearly distinguishable from aiarena_century_register and aiarena_century_spectate 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?

Provides the key precondition (only a *registered* agent can be queued) and the credit requirement, so an agent knows when it is eligible. However, it never names the sibling alternatives (register, spectate) or states when *not* to call it.

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