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 effectively describes the operation as a read-only list function (implied by 'List all'), specifies the source ('GitHub repositories'), and clarifies that these roles are not yet installed ('must be cloned... before installation'). It also describes the return format ('Dictionary with available role repositories and their GitHub URLs'), which is crucial since there's no output schema. However, it doesn't mention potential limitations like rate limits or authentication needs.

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 efficiently structured with three sentences: the first states the purpose, the second adds crucial context about the role state, and the third describes the return value. The example is brief and relevant. Every sentence earns its place with no wasted words.

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's low complexity (0 parameters, no annotations, no output schema), the description is nearly complete. It explains what the tool does, the nature of the roles, and the return format. The main gap is the lack of explicit usage guidelines versus alternatives, but for a simple list tool, this is a minor omission.

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 0 parameters with 100% coverage, so the schema fully documents the lack of inputs. The description appropriately doesn't discuss parameters, which is correct for a parameterless tool. It adds value by focusing on the tool's purpose and output instead.

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 specific action ('List all roles') and resource ('available from GitHub repositories') with additional clarifying context ('directory-based roles'). It distinguishes from sibling tools like 'list_installed_roles' by specifying these are repository-based roles not yet installed.

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 implied usage context by stating 'These roles must be cloned on the Ludus server before installation,' which suggests this tool is used to discover roles for potential installation. However, it doesn't explicitly state when to use this versus alternatives like 'install_role' or 'list_installed_roles,' nor does it mention prerequisites or exclusions.

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