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 'admin only' for the user_id parameter, hinting at permission requirements, but doesn't describe other critical behaviors: whether this is a destructive operation (e.g., invalidates old credentials), what the rotation entails (e.g., generates new keys), potential side effects (e.g., downtime), rate limits, or error conditions. For a credential management tool with zero annotation coverage, this leaves significant gaps in understanding how the tool behaves.

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 concise and structured with a brief purpose statement followed by Args and Returns sections. It avoids unnecessary words, but the Args section could be more informative. The structure is front-loaded with the main action, though the Returns section is vague ('Credential rotation result'). Overall, it's efficient but slightly under-specified in parts.

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 of credential rotation (a mutation operation with security implications), no annotations, and an output schema that likely documents return values, the description is incomplete. It lacks details on behavioral traits (e.g., safety, side effects), parameter usage, and context like when to invoke it. The presence of an output schema reduces the need to explain returns, but other gaps make this insufficient for safe and effective tool use.

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 input schema has 1 parameter with 0% description coverage, and the description adds minimal value. It states 'user_id: Optional user ID (admin only)', which clarifies that it's optional and admin-restricted, but doesn't explain the parameter's role (e.g., whether it rotates credentials for a specific user or defaults to the current range), format expectations, or implications of omitting it. With low schema coverage, the description fails to compensate adequately, leaving the parameter's semantics unclear.

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 the tool 'Rotate credentials for the range', which provides a clear verb ('rotate') and resource ('credentials for the range'). However, it doesn't distinguish this from potential sibling tools like 'get_user_apikey' or other credential-related operations, nor does it specify what type of credentials are being rotated (e.g., API keys, passwords, tokens). The purpose is understandable but lacks specificity about the credential 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 minimal guidance: it mentions 'admin only' for the optional user_id parameter, implying administrative privileges are required. However, it doesn't explain when to use this tool versus alternatives (e.g., if there are other credential management tools), what triggers credential rotation, or any prerequisites like range status. Without explicit when/when-not instructions or named alternatives, this falls short of clear usage guidelines.

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