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 action ('Power off all VMs') but doesn't clarify critical aspects: whether this is destructive (likely yes, but not stated), if it requires specific permissions beyond the admin hint, what happens to running processes, or error handling. The mention of 'admin only' in Args adds some context, but overall, behavioral traits are inadequately covered for a mutation tool.

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 lacks effective structure. The first sentence states the purpose clearly, but the Args and Returns sections are redundant with the schema (which exists) and output schema (present). This adds unnecessary length without new value. A more front-loaded approach focusing on context would improve efficiency.

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 complexity (a mutation affecting multiple VMs), lack of annotations, and low schema coverage, the description is incomplete. It doesn't address safety implications, error conditions, or how 'range' is defined. The output schema exists, so return values needn't be explained, but overall, the description fails to provide sufficient context for safe and effective use.

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 1 parameter with 0% description coverage, and the description adds minimal semantics: it notes 'user_id' is 'Optional user ID (admin only).' This clarifies optionality and a permission constraint, but doesn't explain what 'range' means or how it's determined. Since schema coverage is low, the description partially compensates but leaves gaps, warranting a baseline score.

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: 'Power off all VMs in the range.' This is a specific verb ('Power off') and resource ('all VMs in the range'), making the action unambiguous. However, it doesn't explicitly differentiate from sibling tools like 'batch_power_off_hosts' or 'power_on_range', which would require a 5.

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 'batch_power_off_hosts' (which might handle subsets) or 'power_on_range' (the opposite action), nor does it specify prerequisites or exclusions. The only contextual hint is in the Args section about 'admin only,' but this isn't integrated into usage guidance.

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