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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds value beyond that by disclosing the payload depth (full record with module/lesson outline), which is important since no output schema exists. It does not state what happens for an unknown or malformed slug, which is the main remaining gap.

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?

Two tight sentences with zero filler; the core action is front-loaded and the slug-source guidance follows immediately. Every clause carries information an agent needs.

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 single-parameter read-by-identifier tool, the definition covers action, identifier provenance, return depth and safety via annotations. Only error behavior for invalid slugs is unaddressed, a minor omission given the tool's simplicity.

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?

Schema coverage is 100% and there is only one parameter, so the baseline would be 3. The description goes further by explaining where valid slug values come from (three named sibling tools), giving provenance meaning the schema's "The course slug." does not provide.

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?

States a specific verb and resource ("Get one course or programme"), its scope ("in full by its slug"), and the returned depth ("including its module or lesson outline"). This clearly separates it from the sibling list_/search_ tools that return summaries rather than full detail.

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?

Explicitly routes the agent: slugs come from list_programmes, list_free_courses or search_courses, so this tool is the follow-up call once a slug is known. There is no explicit "do not use when..." exclusion, but the dependency is clear enough to select correctly.

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