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

Annotations already declare readOnlyHint and idempotentHint, so the read-only nature is covered. The description adds critical context: it triggers a confirmation-required browser handoff and does not start or save onboarding, which is unexpected for a list operation. This goes beyond the annotations and reveals a side effect, earning a 4.

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 sentences, front-loaded with the core action, and contains no unnecessary words. The first sentence states the purpose, and the second adds important behavioral nuance, making it highly efficient.

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 a single parameter, an output schema, and robust annotations, the description sufficiently covers the tool's behavior, including the unusual handoff detail. It is complete enough for an agent to select and invoke the tool correctly, and the output schema handles return value documentation.

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%, but the description explicitly mentions 'for the UK or US,' which directly aligns with the region parameter's enum values. This compensates for the lack of schema descriptions and makes the parameter's purpose clear, though it does not explicitly name the parameter.

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 clearly states the tool lists study courses for the UK or US, using a specific verb 'list' and a resource ('study courses'). It distinguishes itself from sibling tools like search_driving_guides and get_driving_guide, which serve different purposes.

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 provides context that this tool lists courses and returns a browser handoff, but it does not explicitly state when to use it over alternatives or exclude sibling tools. The scope (UK/US) is clear, but without direct alternative guidance, usage is implied rather than explicitly directed.

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