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

Annotations already establish read-only and idempotent behavior, so the description adds value by specifying that only countries with jobs are returned and that output includes name and ISO code. This is useful context beyond the annotations, though it does not detail ordering or pagination.

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 action and resource. Every sentence contributes: the first defines the output, the second instructs on usage. No fluff or redundancy.

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 list tool with no parameters and no output schema, the description provides all essential information: what is listed (countries with jobs), the fields (name and ISO code), and how to use the results. It is complete for its simplicity.

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 has zero parameters, so the baseline is 4. The description adds clarity about the output format (ISO country code), which helps users understand how to use the result, even though there are no input parameters to document.

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 countries, specifying the verb 'List' and the resource 'countries with jobs'. It distinguishes itself from siblings by focusing solely on countries as reference data, not jobs, companies, or trends.

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 tells users to use the resulting ISO codes as the country filter in search_jobs, job_trends, and salary_benchmarks, providing clear application context. It does not explicitly name alternatives to avoid, but since this is the only country list tool, the guidance is sufficient.

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