Ludus FastMCP

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool lists users and returns their information, but doesn't describe key behaviors: whether it's paginated, if it requires authentication, what fields are included in the return, or any rate limits. For a read operation with zero annotation coverage, this leaves significant 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 brief but could be more front-loaded. The first sentence clearly states the purpose, but the second sentence ('Returns: List of all users with their information') is somewhat redundant with the first. It's concise but not optimally structured, as the return statement could be integrated more smoothly.

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 simplicity (0 parameters, read-only operation) and the presence of an output schema, the description is minimally adequate. However, without annotations and with behavioral gaps (e.g., no mention of pagination or authentication), it doesn't provide complete context for safe and effective use. The output schema helps, but the description should do more to explain 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?

The input schema has 0 parameters with 100% coverage, so no parameter documentation is needed. The description doesn't add parameter details, which is appropriate. A baseline of 4 is given because the schema fully covers the parameters (none exist), and the description doesn't need to compensate.

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 tool's purpose: 'List all users in the Ludus system.' It specifies the verb ('List') and resource ('users'), and the system context ('Ludus system') provides useful context. However, it doesn't explicitly differentiate from sibling tools like 'get_user' or 'add_user', which would be needed for 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. It doesn't mention sibling tools like 'get_user' (for retrieving a specific user) or 'add_user' (for creating users), nor does it specify prerequisites or appropriate contexts. The agent must 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.