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 states this is a 'Get' operation (implying read-only) and mentions 'admin only' for the user_id parameter, which hints at permission requirements. However, it lacks critical behavioral details: whether this is a real-time or historical query, any rate limits, what happens if user_id is omitted, or how the metrics are formatted/aggregated. The description provides minimal behavioral context beyond the basic operation type.

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 concise with three sentences that cover purpose, parameters, and returns. It's front-loaded with the main purpose first. While efficient, the 'Args' and 'Returns' sections could be integrated more naturally rather than as separate labeled sections, but overall it avoids unnecessary verbosity.

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 has an output schema (which handles return values) and only one parameter, the description provides adequate basic context. However, for a metrics retrieval tool with no annotations, it should ideally explain more about the metrics scope (real-time vs historical, aggregation level) and any constraints. The presence of an output schema reduces the burden, but the description remains somewhat minimal for a tool that presumably returns complex metrics data.

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 description adds some semantic context for the single parameter: it explains that user_id is 'Optional user ID (admin only)', which provides meaning beyond the schema's technical definition. However, with 0% schema description coverage and only one parameter, this represents minimal added value. The description doesn't explain what 'admin only' means in practice or how the parameter affects the returned metrics.

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 states 'Get comprehensive metrics for the range' which provides a basic verb+resource combination. However, it's vague about what 'comprehensive metrics' specifically entails compared to sibling tools like 'get_deployment_metrics' or 'export_metrics', lacking clear differentiation. The purpose is understandable but not specific enough to distinguish it from similar tools.

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 a parameter constraint rather than usage context. There's no indication of prerequisites, timing, or comparisons to sibling tools like 'get_deployment_metrics' or 'export_metrics'.

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