list_categories

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

With no annotations, the description carries the burden of disclosure. It clearly states the return format (JSON array with id, name, parent, depth, course count) and adds semantic context about category hierarchy. It doesn't cover ordering, pagination, or error/authentication behavior, but for a parameterless list tool this is reasonably transparent.

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 compact, front-loaded with the action, and includes only essential context and return details. Every sentence earns its place: purpose, background, and output format.

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 simplicity (no params, simple list output) and the presence of an output schema, the description is complete. It explains what categories are, what is returned, and is fully sufficient for an agent to select and invoke this tool correctly.

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 tool has zero parameters, so schema coverage is vacuously 100%. Per the rubric, baseline for 0 parameters is 4. The description adds no parameter-specific info, but none is needed.

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 lists course categories, specifying the Moodle-specific meaning of categories as hierarchical organizers by faculty, degree, year, or period. This verb+resource combination uniquely distinguishes it from sibling list tools like list_courses, list_groups, etc.

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 useful context on what categories are and how they relate to courses, which implies when to use this tool (when you need the category hierarchy). However, it doesn't explicitly state when not to use it or mention alternative tools for related tasks, so it falls just short of a 5.

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