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

Annotations declare readOnlyHint=true and openWorldHint=false, so safety is already covered; the description usefully adds the fee-investigation workflow and that specific MT103 fields reveal each deduction. It goes beyond the annotations by disclosing the analytical process, though it does not mention input validation limits or error behavior.

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 core purpose and the when-to-use condition are front-loaded before the examples. Four examples is slightly more than needed but each demonstrates a distinct mode (SEPA, SWIFT, domestic, fee investigation), so the size is largely justified.

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?

An output schema exists, so return values need not be restated; the description nonetheless summarizes them (cost, speed, requirements, charge options, guidance). With only two required, fully documented params and clear annotations, the definition is effectively complete, missing only minor edge-case guidance.

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 country-code parameters are fully documented in the schema (ISO 3166-1 alpha-2). The description adds no format or edge-case detail beyond the schema, and the examples only reinforce a format the schema already states, so the baseline 3 applies.

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 (compare payment methods) plus a second capability (fee investigation for a country pair). It explicitly enumerates the compared options (SEPA vs SWIFT vs domestic) and the charge-option model (OUR/SHA/BEN), so an agent can distinguish it from siblings like transfer_cost or ssi_lookup without opening a schema.

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?

Provides a clear triggering condition ("use this when the beneficiary received less than expected") and four examples that map country-pair shapes to expected outputs (SEPA → SCT, non-SEPA → SWIFT, domestic → CHAPS/FPS). It lacks explicit when-not usage or named sibling alternatives, so it stops short of a 5.

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