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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so 'Read-only' in the description is largely redundant. The description does earn credit for disclosing the return shape (ids, dose times, phases with intake/break periods and dose text, dates), which matters because there is no output schema. It says nothing about ordering, freshness, or whether courses omitted/paused are included.

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?

A single well-formed sentence, front-loaded with the return content followed by the safety note. Efficient, with only the minor redundancy of restating 'Read-only' from the annotations.

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 zero-parameter read tool with rich annotations and no output schema, the description covers what an agent needs in order to interpret the result: the key fields and the nested phase structure. Missing only edge details such as ordering or whether historical/inactive courses are included.

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 there is no parameter semantics to explain and the baseline is 4. The description correctly avoids inventing filters the schema does not support.

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 ('Returns the user's courses') and enumerates the payload content: ids, dose times, phases, start/end dates. It is distinguishable from siblings like zarok_get_plan or zarok_get_week_summary by the dose/phase detail, though it never names an alternative explicitly.

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?

There is no guidance on when to call this versus other read tools in the family (get_plan, get_week_summary, get_period_stats). The only usage-ish statement is 'Read-only', which is a safety trait, not a selection rule.

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