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

The description adds meaningful behavioral context beyond the annotations: the module is placed at the end of the course, only module metadata is created here, and module order is mutable later. Annotations only indicate a non-read-only mutation, so this placement and scope information is useful.

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 two concise sentences with no filler. It front-loads the key placement behavior, then gives the most important sibling-tool pointer and reorderability note.

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 create operation with two straightforward parameters and an output schema available, the description covers what the tool does, where the module is placed, what it does not do (lessons), and how ordering can be handled. Nothing essential is missing for correct invocation.

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% and the description does not define course_id or title. It only refers to the course and module conceptually, leaving the parameter meanings to self-descriptive names. With low schema coverage, the description should compensate but does not.

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 clear action: a module is appended to the end of a course. It also explicitly distinguishes this tool from create_lesson by noting that lessons are added separately, so an agent can tell what resource this tool operates on.

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 explicitly routes lesson creation to create_lesson ('Уроки добавляются в модуль отдельно, create_lesson'), and it tells the agent that module order can be adjusted later, so ordering is not a concern at creation time. This is clear when-to-use and when-not-to-use guidance.

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