Open Serper.live markets

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

Annotations already declare readOnly=true, idempotent=true and openWorld=true. The description adds real context beyond them: that every market supports desktop and mobile, and that the call is free with no token required, which lowers the agent's hesitation to call it. It does not describe the response shape, but with no parameters there is little else to disclose.

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?

Three short sentences, each carrying distinct information (what it returns, when to call it and what to do next, availability/cost). Nothing is padded or repeated from the title.

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?

No output schema exists, and the description compensates by describing what is returned (country codes plus default interface language) and the availability guarantees. With no input parameters and only an open lookup role, nothing an agent needs is missing.

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 the baseline is 4. The description goes slightly further by explaining the semantics of the returned code (usable as the `country` argument of sibling tools), which is the only 'value' semantics this parameterless tool needs.

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 ('List the countries Serper.live can search') and adds the scope of what each entry carries (default Google interface language). It is immediately distinguishable from google_search and domain_position, which it references as consumers.

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?

Gives an explicit trigger ('Call it when unsure whether a market is open') and the follow-up flow ('pass a returned code as country to google_search or domain_position'). The agent knows both when to call it and what to do with the result.

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