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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds meaningful behavior: returns ranked exchanges, applies CoinRebate discount, and supports optional compliance filtering by country.

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?

Two sentences with no fluff: the main action and ranking logic are front-loaded, and the optional country parameter is placed second. Every word earns its place.

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?

Given the simple read-only nature, full schema coverage (100%), annotations indicating safety, and an existing output schema, the description provides enough for an agent to invoke correctly: purpose required, country optional, and ranking criterion clear.

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% already documents both parameters, including the country's purpose. The description's mention of 'Pass country code for compliance-filtered results' largely echoes the schema, adding no significant new semantics beyond the required purpose enum.

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 uses a specific verb 'Compare' with clear resource 'trading fees across all exchanges' and scopes to spot or futures. It also states the output is ranked by lowest fee after rebate, which distinguishes it from sibling tools like get_exchange_fees or get_compliant_exchanges.

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?

Clear context: the tool is for comparing fees across all exchanges for spot/futures, with an optional country for compliance filtering. It doesn't explicitly name alternatives or when-not-to-use, but the 'all exchanges' scope and ranking behavior make its use case evident.

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