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

Without annotations, the description carries full burden for behavioral transparency. It explains that the tool evaluates methods, explains charge options (OUR/SHA/BEN), and returns cost, speed, requirements, and step-by-step fee investigation guidance. It does not mention side effects, but as a comparison/investigation tool, this is acceptable. It could disclose if it modifies data or has external calls, but given the nature, it's reasonably transparent.

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 well-structured and front-loaded with the main purpose, followed by details and examples. Every sentence adds value—no filler. It is concise yet comprehensive, using bullet points and examples effectively without being verbose.

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 tool's complexity (multiple payment methods, fee investigation), the description is complete. It covers inputs, behavior, and examples. Since an output schema exists (as indicated by context signals), the description does not need to enumerate return fields. The examples cover the main use cases, making the tool easy to use.

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 documentation coverage is 0% (no descriptions in schema properties), so the description must fully explain parameters. It does so clearly: both parameters (source_country, dest_country) are described as ISO 3166-1 alpha-2 codes, and examples are provided for each use case. This fully compensates for the missing schema 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 clearly states the tool's purpose: compare payment methods and investigate fee deductions for a country pair. It lists specific methods (SEPA, SWIFT, domestic) and explicitly mentions fee investigation, distinguishing it from sibling tools that might focus on single-country or general banking data.

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 description provides clear usage context, including when to use the tool for fee investigation ('when the beneficiary received less than expected'). It includes multiple examples showing different scenarios (SEPA, non-SEPA, domestic). However, it does not explicitly state when not to use this tool or mention alternatives among siblings, though the examples imply some differentiation.

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