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

Beyond the annotations, the description discloses important behaviors: the password is auto-generated and must be shown once, verification is required before generating images, and failures include already_exists, rate_limited, and failed. This meaningfully informs the agent about side effects and error handling without contradicting the annotation hints.

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 well-structured with Args and Returns sections, and every part earns its place: creation, one-time password display, verification, downstream API-key steps, and failure modes. It is detailed without being redundant.

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 a verification side effect and downstream steps, the description covers the full lifecycle: what happens immediately, what the user must do, what the agent should do next, and what errors to expect. The output schema exists, and the description still adds useful return semantics, so nothing essential is missing.

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?

The schema already documents the email parameter at 100% coverage, so the baseline is 3. The description adds operational meaning by explaining that the email is used to create the account and by giving guidance on the already_exists failure, such as asking the user for their password or a different email. This goes beyond the schema but does not add format 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 a specific verb and resource: 'Create a new Maginary account for the given email address.' It is clear and actionable, though it does not explicitly contrast itself with the sibling create_wallet_account, leaving the agent to infer the distinction from the 'Maginary account' wording.

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 a clear usage flow: create the account, show the password once, wait for verification, then use manage_api_key and configure_api_key. It does not explicitly state when not to use this tool or name alternatives, but the downstream instructions make the intended context concrete.

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