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

Annotations already provide read-only, idempotent, and open-world hints. The description adds meaningful behavioral context by disclosing data sources (ECB FX rates, World Bank remittance price data) and what outputs to expect (cost breakdown, FX rates, settlement time estimates). No contradictions with annotations.

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 sentences, front-loaded with the core purpose, and every sentence adds value (purpose, input/output, data sources). No redundant or vague wording.

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 complexity, schema coverage, and presence of an output schema, the description is complete enough. It explains what the tool does, key inputs, outputs, and data sources. It could mention optional currency inputs explicitly, but those are already in the schema.

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 mentions the key required parameters (source/destination countries, amount) but adds little beyond that—for instance, it does not elaborate on currency parameters or async behavior, which are already documented in the schema.

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 function: comparing cross-border payment rail costs (SWIFT, SEPA, local ACH, stablecoins) including FX fees and settlement times. This is a specific verb+resource+scope that distinguishes it from related tools like fx_rate or x402_payment_flow_analyzer.

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 gives clear context for use: 'Ideal for optimizing international payment strategies and reducing transaction expenses.' It does not explicitly name alternatives or exclusions, but the purpose is unambiguous enough for an agent to decide when to invoke it.

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