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

No annotations are provided, and the description does not disclose any behavioral traits beyond the bare action of registering. It does not mention side effects, required permissions, email verification, password requirements, or what happens on duplicate registration. The full burden is on the description, and it fails to add context.

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 a single concise sentence that earns its place with a clear verb-object structure. It avoids fluff and is appropriately front-loaded, focusing on the essential action.

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 tool with three required parameters, no output schema, and no annotations, the description is incomplete. It does not explain return values, success indicators, error conditions, or any additional context (e.g., whether the account is immediately active). The description is minimal and leaves too much for the agent to infer.

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%, and the description does not mention any parameters. While the parameter names (email, password, username) are self-explanatory, the description adds no meaning about constraints, formats, or interdependencies. The low coverage requires description compensation, which is absent.

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 'Register a new user account' uses a specific verb ('register') and resource ('user account'), clearly indicating the tool's purpose. It implicitly distinguishes from sibling 'sign_in' (which handles authentication for existing users), making it obvious this tool is for new account creation.

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?

No guidance is provided on when to use this tool versus alternatives like 'sign_in'. The description is purely a statement of function with no context about prerequisites, common scenarios, or exclusions.

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