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

Annotations already cover read-only/idempotent/non-destructive safety; the description adds beyond that: it is a static file, requires no auth, and contains over 280 reporters. It also clarifies the default behavior (groups included) and the return codes, which helps an agent plan calls.

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?

Six compact sentences, each carrying a distinct piece of information: purpose, return fields, filtering, group behavior, scale, and source/auth. Front-loaded with the main action.

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 two-parameter reference lookup with an output schema and safety annotations, the description covers purpose, usage, scale, and operational traits (no auth, static file). No critical gaps.

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 coverage is 100%, so the baseline is 3. The description reinforces the search and include_groups semantics with an additional example (ASEAN) and hints at data scale, but doesn't add meaning beyond what the schema already provides.

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 action ('List all countries and country groups that report trade statistics to UN Comtrade') with a clear resource and scope. It also distinguishes itself from sibling trade query tools by noting that the returned codes are 'needed for other comtrade tools'.

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?

Provides context that this is a prerequisite reference ('needed for other comtrade tools') and gives concrete filter guidance (search by name/ISO, exclude groups with include_groups=false). It doesn't explicitly name alternative siblings or state when not to use, but the usage context is sufficient for a simple reference list.

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