Ludus FastMCP

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states this is a creation operation but doesn't mention authentication requirements, permission levels needed, whether the operation is idempotent, or what happens on failure. For a user creation tool with zero annotation coverage, this leaves significant behavioral gaps.

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 clear sections (purpose, args, returns) and uses minimal sentences. Every sentence earns its place, though the 'Returns' section could be slightly more specific given the output schema exists. The structure is front-loaded with the core purpose first.

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 user creation tool with no annotations but an output schema, the description covers the basic purpose and parameters adequately. However, it lacks important context about authentication requirements, permission levels, and error conditions. The existence of an output schema reduces the need to describe return values, but behavioral transparency remains incomplete.

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 description explicitly documents all 4 parameters with clear semantic explanations beyond the schema's 0% description coverage. It explains what each parameter represents (username, password, admin privileges, optional Proxmox username), adding significant value over the bare schema. The only minor gap is not explaining format constraints for parameters like password complexity.

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 ('Add a new user') and resource ('to the Ludus system'), distinguishing it from sibling tools like 'remove_user' or 'list_users'. It provides a complete verb+resource statement that leaves no ambiguity about the tool's function.

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. While it's clear this creates users, there's no mention of prerequisites (e.g., admin permissions), constraints, or when to choose this over other user management tools. The agent must infer usage context 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.