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

With no annotations, the description carries the burden and does signal that this is a read operation rather than a mutation. It also discloses the scope of returned content ('summary and 100-lesson plan'), which is useful given there is no output schema; however, it omits error behavior and any access or rate-limit constraints.

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 a single front-loaded sentence with no wasted wording. It puts the verb, resource, content scope, and identifier source in one efficient statement.

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 simple read tool with one required parameter and no output schema, the description covers the core action, the lookup key source, and the broad shape of the returned content. It is nearly complete, with only minor gaps around error handling and exact return structure.

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 description coverage is 0%, so the description should compensate. It does add meaning by saying the slug comes from search_subjects, which helps an agent obtain a valid value, but it does not describe the slug format or validity requirements, so compensation is partial.

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 a specific verb and resource: 'Read a Teach Me course ... by its slug.' It also scopes the returned content as 'summary and 100-lesson plan' and distinguishes the resource from the sibling 'search_subjects' by identifying that tool as the source of the slug. The course-vs-lesson distinction also separates it from get_lesson.

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 phrase 'slug (from search_subjects)' gives an implied usage chain and prerequisite, but the description never explicitly says when to use this tool instead of get_lesson or what to do if the course slug is unknown. Usage is inferable but not fully spelled out.

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