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 mentions that the operation is faster for parallel processing and returns results including successes and failures, which adds useful context beyond basic functionality. However, it does not cover critical aspects like permissions (e.g., admin requirements hinted by 'user_id'), potential destructive effects, rate limits, or error handling details, leaving 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 and appropriately sized. It starts with a clear purpose statement, follows with usage context, details parameters and returns, and includes an example. Each sentence adds value without redundancy, making it easy to scan and understand quickly.

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 complexity (a batch mutation tool with 4 parameters, no annotations, and no output schema), the description is moderately complete. It covers purpose, usage, parameters, and returns, but lacks details on behavioral traits like authentication needs, side effects, or output structure specifics. For a tool with no structured safety or output information, more context on risks and results would improve completeness.

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 provides a clear 'Args' section explaining each parameter: 'vm_names' (list of VM names), 'snapshot_name' (name for snapshots), 'description' (optional description), and 'user_id' (optional user ID, admin only). This adds meaningful semantics beyond the bare schema, though it could elaborate on format constraints (e.g., VM name validation).

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: 'Create snapshots for multiple VMs in parallel.' It specifies the verb ('Create snapshots'), the resource ('multiple VMs'), and distinguishes it from sequential operations. This is specific and differentiates it from sibling tools like 'snapshot_host' (singular) or 'batch_remove_snapshots' (different action).

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 clear context on when to use this tool: 'This is much faster than creating snapshots sequentially, especially for large numbers of VMs.' It implies usage for efficiency with multiple VMs but does not explicitly state when not to use it or name specific alternatives like 'snapshot_host' for single VMs. The guidance is helpful but lacks explicit exclusions or named sibling comparisons.

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