brilliant-directories-mcp

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

With no annotations provided, the description carries the full burden. It discloses the core behavior (validation without profile data) but lacks details about authentication mechanisms, error responses, session creation, or security implications. The description is accurate but minimal for a security-critical operation.

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?

Two tightly focused sentences with zero waste. The first states the core purpose, the second provides critical usage guidance. Every word earns its place in this efficient description.

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 security-critical authentication tool with no annotations and no output schema, the description is adequate but minimal. It covers the basic purpose and usage relationship with 'getUser', but lacks details about return values, error conditions, or security context that would be helpful for an agent.

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?

With 0% schema description coverage for both parameters, the description adds meaningful context by specifying that these are 'email/password' credentials for validation. This clarifies the purpose beyond the bare schema, though it doesn't provide format or constraint details beyond the schema's email format.

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 clearly states the specific action ('Validate user credentials') and resource ('email/password'), distinguishing it from sibling tools like 'getUser' and 'verifyToken'. It explicitly differentiates from 'getUser' by stating it does not return profile data.

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 provides explicit guidance on when to use this tool ('Validate user credentials') and when to use an alternative ('use getUser after'). It clearly distinguishes this authentication tool from data retrieval tools in the sibling list.

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