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 mentions 'admin only' for user_id, hinting at permission requirements, but fails to address critical aspects like whether the snapshot is destructive, reversible, or impacts VM performance, leaving significant gaps 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 well-structured with clear sections (Args, Returns) and uses bullet-like formatting. It's front-loaded with the core purpose, though the 'Returns' section could be more informative given the output schema exists, making it slightly less efficient.

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 a mutation tool with 4 parameters, 0% schema coverage, no annotations, but an output schema, the description provides basic purpose and parameter info. It lacks behavioral details (e.g., side effects, error handling) and deeper usage context, making it minimally viable but incomplete for safe operation.

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 lists all 4 parameters with brief explanations (e.g., 'Optional snapshot description'), adding basic semantics beyond the schema. However, it doesn't detail format constraints, examples, or interactions between parameters, resulting in adequate but incomplete coverage.

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 ('Create a snapshot') and resource ('of a host'), making the purpose immediately understandable. However, it doesn't differentiate from sibling tools like 'batch_snapshot_hosts' or 'list_snapshots', which would require explicit comparison to earn 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?

No guidance is provided on when to use this tool versus alternatives like 'batch_snapshot_hosts' or 'schedule_snapshots'. The description lacks context about prerequisites, timing, or constraints, offering minimal usage direction.

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