Ludus FastMCP

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions 'admin only' for user_id, which hints at permission requirements, but doesn't describe what 'stop testing state' entails—whether it's reversible, what side effects occur, or how it interacts with other operations. The return value is mentioned but not explained, leaving significant gaps in understanding the tool's behavior.

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 and structured with separate sections for Args and Returns, making it easy to parse. However, the core purpose statement 'Stop testing state for the range' is somewhat vague and could be more precise. The sentences earn their place but could be more informative.

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 one parameter with 0% schema coverage and an output schema exists (though not detailed in the description), the description provides basic parameter info and mentions a return value. However, for a tool that likely modifies system state (implied by 'stop'), the lack of annotations and minimal behavioral context makes it incomplete—more details on effects and usage are needed for full understanding.

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 includes an Args section that documents the user_id parameter as 'Optional user ID (admin only)', adding meaning beyond the input schema which has 0% description coverage. However, with only one parameter and partial coverage, it provides basic but incomplete context—it doesn't explain what happens if user_id is omitted or the implications of the admin restriction. This meets the baseline for minimal viable documentation.

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 'Stop testing state for the range' which provides a basic verb+resource combination, but it's vague about what 'testing state' means and how this differs from similar operations like 'abort_and_remove_range' or 'abort_range_deployment' among the many sibling tools. It doesn't clearly distinguish itself from alternatives.

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 minimal guidance with 'admin only' mentioned for the user_id parameter, but it doesn't explain when to use this tool versus other stopping/aborting tools in the sibling list, nor does it specify prerequisites or appropriate contexts for invocation. No explicit alternatives or exclusions are provided.

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