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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the base safety profile is covered. The description adds valuable operational context: the $0.02/call payment requirement via x402, and the 402 response without payment. It also discloses the return format. No contradictions.

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 four sentences, front-loaded with the main purpose, then usage, payment, and return format. Every sentence earns its place with no wordiness.

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?

The description includes the purpose, usage context, payment requirement, failure mode, and return array structure. With annotations covering read-only/idempotent behavior and the schema covering parameters, this is nearly complete. It could optionally mention when country/direction are optional, but the schema already handles that.

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 the baseline is 3. The description reinforces that country and direction are relevant ('in a specific country/direction'), but it does not add new semantic detail beyond the schema's parameter descriptions.

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 opens with 'Get carrier-specific surcharges' — a specific verb and resource — and enumerates surcharge types (BAF, CAF, PSS, EBS). It also distinguishes itself from shippingrates_total_cost by noting that tool includes surcharges automatically. However, it does not differentiate from other surcharge-related siblings like local_charges or cfs_tariffs.

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?

Explicitly states when to use: 'Use this to understand surcharge exposure for a carrier in a specific country/direction.' It also names an alternative: 'For a complete cost breakdown, use shippingrates_total_cost which includes surcharges automatically.' This provides clear context and exclusions.

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