List countries

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety and openness profile is covered. The description adds only that the payload is Metal Archives' own country code vocabulary, which is genuinely useful for filtering, but says nothing about format, size, or completeness of the list.

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 short line with zero filler, and the resource is front-loaded ahead of the usage clause. It is a fragment rather than a complete sentence, which slightly weakens it but costs no tokens.

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?

There is no output schema, but 'Country codes' plus the stated consumers of those codes tells an agent what it will get and why. It could go one step further and confirm the return shape (e.g., code list only vs. code+name pairs), which is the only real gap for a no-param lookup.

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?

Zero parameters, so the baseline of 4 applies; there is nothing for the description to disambiguate. The mention of usage contexts (country filters, browse_bands) gives the only semantic anchor relevant to a no-input tool.

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 names the exact resource ('Country codes Metal Archives uses'), so an agent knows it returns the canonical code list rather than country data or band results. It is a telegraphic fragment with no verb, but the title plus resource name make the purpose unambiguous.

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 parenthetical '(for country filters and browse_bands)' implies this is an input-lookup for country filter parameters, which is useful routing information. However, it never states explicitly when to call it (e.g., 'call before filtering by country to get valid values') and names no alternatives or exclusions.

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