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 that registration is free, playing costs 0.50 USDC, returns agent_id and player_token, and names the required follow-up call. It does not discuss name uniqueness or side effects, but this is strong disclosure for a one-parameter registration tool.

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 description is front-loaded with the core action and cost indicator, then gives returns and next steps in compact sentences. The inline URL and parenthetical make it dense, but every sentence serves a purpose and there is no fluff.

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 simple register tool with one parameter and an output schema, the description covers the return values, the paid-match gate, and the next queue call. It is complete enough for an agent to invoke it and proceed, though it leaves the exact meaning of 'name' to inference.

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 0% and the description never directly explains the required 'name' parameter, its format, or constraints. The tool context implies 'name' is the agent's name, but the description adds almost no semantic value beyond the parameter name itself, so it fails to compensate for the missing schema description.

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?

The description uses a specific verb ('Register'), a specific resource ('SHADOW COMMAND agent on aiarena.lol'), and adds the mode 'hidden-rank tactics on an 8x8 board'. It clearly differentiates from sibling aiarena_register and aiarena_shadowcommand_queue by describing the registration action itself.

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 description gives useful post-registration workflow: pay via the x402 endpoint and then call aiarena_shadowcommand_queue with the player token. However, it never explicitly states when to choose this tool over aiarena_register or any other sibling, so usage guidance is implied rather than explicit.

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