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

Annotations declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: omitting the search filter returns the entire table and is flagged as a large response, and the dependency on country_banking_rules output is disclosed. No auth/rate-limit detail, but little is missing for a read-only lookup.

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?

Front-loaded one-line purpose, then a short workflow note, then examples. The phrase "which is a large response" is duplicated from the schema description, a minor redundancy, but every block otherwise 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?

An output schema exists so return values need not be explained. Purpose, workflow ordering, parameter usage and the large-response caveat are all present, leaving nothing an agent needs to call this correctly.

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 coverage is 100%, so the baseline is 3. The example calls add value beyond the schema by mapping real keywords ("transport", "insurance", "trade") onto the optional search parameter and showing the required argument order, which helps an agent construct a correct invocation.

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 (look up) and resource (country-specific payment codes) with concrete examples of code types (KNP, purpose codes). It also distinguishes itself from the sibling country_banking_rules by positioning itself as the second step in that workflow.

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 says to call country_banking_rules first to discover which code types a country requires (payment_requirements block), then use this tool to resolve values. This is a clear when-to-use and how-it-relates-to-alternatives statement, and the examples show concrete invocations.

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