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

No annotations exist, so the description must carry the full burden. It usefully discloses the return values (agent_id, player_token) and a cost model, but the 0.50 USDC x402 payment detail belongs to a separate match-entry endpoint, which could mislead an agent into thinking registration itself is paid; auth requirements and idempotency are unstated.

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?

The opening sentence is front-loaded and useful, but the remainder is a dense run-on mixing liar's-dice rules with an unrelated payment endpoint, diluting the operative instruction.

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 spelled out, and the game rules give helpful flavor, but for a 1-param registration tool the description omits the parameter's meaning and the preconditions/sequencing an agent needs to actually invoke it correctly.

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?

One required parameter ('name') with 0% schema description coverage, and the description never mentions it — no naming rules, uniqueness, or format. With no annotations to fall back on, the description fails to compensate for the coverage gap.

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 ('Register an agent for AIARENA BLUFFDUEL'), names the venue and the game type, and is clearly distinguishable from the sibling aiarena_bluffduel_queue and aiarena_bluffduel_spectate. An agent can identify the tool without opening the 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?

The '[FREE]' marker and the paid-entry note imply that registration is the free first step before queuing, but no explicit sequencing or 'use this instead of X' routing is given against bluffduel_queue/spectate. Usage can be inferred but is not stated.

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