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

Annotations already mark it readOnly, idempotent, and non-destructive. The description adds valuable behavioral context beyond that: it reports coverage ratio (null when denominator unknown), declares vs retrievable counts, and guarantees that courses without retrievable text are listed in gaps with a reason and 'nothing is silently dropped.' This is rich and accurate, with no contradiction.

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 front-loaded with the critical usage directive and then lists exactly what the tool returns. It is a bit long, but every sentence carries distinct information (revision, normalization version, counts, ratio, per-course breakdown, gap behavior). No filler.

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?

For a no-argument read-only tool with an output schema, the description is complete: it explains the purpose, when to call it, what it returns, edge cases (null ratio, gaps), and the guarantee that nothing is silently dropped. An agent has everything needed to invoke it 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?

There are zero parameters, and the schema is an empty object with 100% coverage. The description explicitly says 'No arguments,' which is harmless but repeats the schema. With no parameters to explain, the baseline of 4 is appropriate.

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 names a specific resource ('catalog manifest and coverage'), a clear verb ('returns the published revision...'), and a specific use ('Use first, before reading modules in bulk'). It distinguishes itself from bulk module-reading by stating it reveals what can actually be read, so an agent can tell it apart from getCourseModules/getModuleContent.

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?

It explicitly states when to use it ('Use first, before reading modules in bulk'), which is strong usage guidance. It does not explicitly name alternative tools or state when not to use it, but the pre-flight instruction is clear enough to route the agent correctly.

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