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

The annotations declare readOnlyHint=true and idempotentHint=true, but the description says 'Create a new player account' and warns that a random password is generated with no recovery. This is a direct annotation contradiction: creating an account is a mutating operation and a random password makes the call non-idempotent. Therefore the description scores 1.

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 dense but every sentence carries useful information: purpose, prerequisite, empire options, username constraints, and password behavior. The main structural weakness is that nearly everything is packed into one long parenthetical, which hurts scannability but does not add irrelevant content.

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 registration tool with 3 required parameters and no output schema, the description covers the essential operational details: the required registration code, valid empire choices with playstyle meanings, username format rules, and the crucial warning about saving the randomly generated password. It lacks an explicit response shape, but the password warning addresses the most important return behavior.

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%, so the baseline is 3. The description adds meaningful semantic context beyond the schema by explaining what each empire specializes in, such as solarian (mining/trade), voidborn (stealth/shields), and crimson (combat). It also clarifies username formatting rules and the registration code source, enriching the raw schema constraints.

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 opens with 'Create a new player account and join the galaxy,' stating a specific verb, resource, and outcome. This clearly distinguishes the tool from auth-related siblings like login and login_link, and it does not merely restate the tool name.

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 implies usage: it is for creating a new account, as evidenced by 'new player account' and the registration_code requirement. However, it never explicitly contrasts this with alternatives such as login, nor does it state when not to use this tool, so guidance is only 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.