get_best_referral

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

Annotations already declare the operation read-only and idempotent, and the description adds useful behavioral details beyond those annotations: what is returned (referral code, discount percentage, signup URL) and the compliance role of country. No contradiction exists.

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 three short sentences, front-loaded with the tool's main purpose, and every sentence adds useful information: action, return value, and compliance guidance. There is no filler or repetition.

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 2 parameters and no output schema, the description covers what the tool does, what it returns, and how an optional input affects behavior. It could be slightly more explicit about edge cases like unsupported exchanges, but it is sufficiently complete for an agent to invoke it confidently.

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 100%, so both parameters are already well documented. The description adds some context like 'maximum fee discount' and the compliance purpose of country, but it does not heavily extend what the schema already explains.

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 a specific verb and resource: get the best referral/signup link for an exchange. It also gives the selection criterion (maximum fee discount), which distinguishes it from sibling tools like get_exchange_fees or compare_fees.

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?

It clearly conveys when to use the tool: when a referral/signup link for a specific exchange is needed. It even provides contextual guidance for the optional country parameter (compliance verification). It does not explicitly mention alternatives or when-not-to-use cases, but enough context is present.

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