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

With no annotations, the description carries the full burden and discloses key behavior: no authentication required, account creation with 10 free credits, returned api_key/mcp_url/app_url, and an email notification to the user. It omits error conditions, email uniqueness rules, and security caveats around the returned API key.

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 four short sentences, front-loads the core action, then covers returns, auth requirements, and the email side effect. There is no redundant or wasted text.

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 signup tool with no annotations and no output schema, the description adequately covers purpose, return values, authentication, and the email notification. However, given low parameter coverage and no annotations, it should say more about the name and agent_name parameters and about failure/duplicate-account 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 description coverage is only 33%, so the description should compensate. It mentions only the email parameter ('com o e-mail dele'), leaving name and agent_name undocumented in the description; agent_name has a brief schema description, but name remains unexplained.

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 states a specific verb and resource: 'Cria a conta do usuário' (creates the user account), plus the credited benefit of 10 free credits/certidões. It is clearly distinct from sibling actions such as account management or create_api_key, as it describes initial registration.

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 says 'Funciona sem autenticação' (works without authentication), which is useful context for when the tool can be called. However, it does not explicitly compare against alternatives like account or create_api_key, nor does it state what to do if an account already exists.

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