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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=true), so the bar is lower. The description still adds real behavioral value by disclosing the response is an envelope `{ coursesForUser: CourseSummary[] }` rather than a bare array, which matters because there is no output schema. It does not mention pagination or result limits, so it stops short of a 5.

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?

Short and front-loaded, but the return shape is stated twice in two sentences ('as `{ coursesForUser: CourseSummary[] }`' and again 'returns an ENVELOPE `{ coursesForUser: CourseSummary[] }`'), which is redundant. The endpoint path and trailing-slash note are useful, but the duplication costs it.

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?

With no input parameters and no output schema, the only thing an agent needs beyond the annotations is the return shape, and the description supplies it along with the underlying endpoint. Absent detail on pagination or whether results are capped keeps it from a 5.

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 takes zero parameters, so per the rubric the baseline is 4. Nothing about arguments needs explaining and the description does not invent any.

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: it returns every saved course, which cleanly separates it from the single-course siblings get_course and get_course details. It never names a sibling explicitly, but the scope word 'Every' does the differentiation work on its own.

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?

Usage is implied rather than stated: 'Every saved course' makes clear this is the list-all option versus get_course for one course, but there is no explicit when/when-not guidance and no mention of alternatives such as filtering or searching. With no parameters there is little to mis-select, so this is adequate but not instructive.

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