n8n MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the tool retrieves user data but omits critical details: whether this is a read-only operation, what permissions are required, how errors are handled (e.g., invalid IDs), or the format of returned data. This leaves significant gaps for a tool that likely interacts with sensitive user information.

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, direct sentence with zero wasted words. It front-loads the core purpose ('Get user') and efficiently specifies the key input constraint ('by ID or email address'), making it easy to parse quickly.

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?

Given the tool's moderate complexity (2 required parameters, no output schema, and no annotations), the description is incomplete. It doesn't explain what data is returned (e.g., user object fields), error conditions, or authentication requirements, which are essential for an agent to use this tool effectively in a real-world context.

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 description coverage is 0%, meaning neither parameter (clientId, idOrEmail) is documented in the schema. The description mentions 'ID or email address' which partially explains idOrEmail, but it doesn't clarify clientId at all or provide examples (e.g., format of IDs). This fails to compensate for the schema's lack of documentation.

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 action ('Get user') and the target resource ('by ID or email address'), making the purpose immediately understandable. However, it doesn't differentiate this tool from sibling tools like 'list-users' or 'delete-user', which would require explicit comparison to achieve a perfect score.

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 no guidance on when to use this tool versus alternatives like 'list-users' for browsing all users or 'delete-user' for removal. It lacks context about prerequisites (e.g., authentication needs) or typical use cases, leaving the agent to infer usage from the tool name alone.

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