Ludus FastMCP

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

No annotations are provided, so the description carries full burden. It states 'List all hosts in range' which implies a read-only operation, but doesn't disclose behavioral traits such as pagination, sorting, filtering beyond the optional user_id, rate limits, authentication requirements, or what 'range' refers to in context. The mention of 'admin only' hints at permissions but is vague.

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 appropriately sized with three sentences: purpose, args, and returns. It's front-loaded with the main action, and each sentence serves a clear function without waste. Minor improvement could be integrating the args/returns more seamlessly, but it's efficient overall.

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 1 parameter with 0% schema coverage and no annotations, the description partially compensates by explaining the parameter. An output schema exists, so return values needn't be detailed. However, for a tool in a complex server with many siblings, it lacks context on 'range' definition, permissions, or behavioral nuances, making it minimally adequate but with clear gaps.

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?

Schema description coverage is 0%, so the description must compensate. It adds meaning by explaining 'user_id: Optional user ID (admin only)', which clarifies the parameter's optionality and admin restriction. However, it doesn't detail the 'range' context or other implicit parameters, leaving gaps. With 1 parameter partially documented, baseline 3 is appropriate as it adds some value but not fully.

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 verb ('List') and resource ('hosts in range'), making the purpose evident. It distinguishes from siblings like 'list_ranges' or 'list_templates' by specifying 'hosts', but doesn't explicitly differentiate from similar tools like 'list_vm_skeletons' or 'list_networks' that might overlap in scope.

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 mentions 'admin only' for the user_id parameter, but this is parameter-specific and doesn't address broader usage contexts, prerequisites, or comparisons with sibling tools like 'get_range' or 'list_all_ranges_detailed' that might list hosts indirectly.

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