Swiss Clearing Lookup

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 safety profile is covered. The description adds meaningful behavioral context beyond annotations: the data source and refresh cadence (1,100+ SIX BankMaster entries, monthly), the breadth of payment rails covered, and a clear cost of 0.003 USDC. This gives the agent useful expectations about freshness, scope, and billing.

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 with labeled sections (USE WHEN, BACKED BY, RETURNS, COST) and front-loads the core purpose. Its length is justified by the richness of the lookup results and the use-case list. Minor points: the capitalized claim 'THE DEEPEST SWISS CLEARING DATA IN ANY PUBLIC API' is promotional rather than operational, and some data-depth information is repeated across sections.

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?

With a single documented parameter, an output schema covering return fields, clear use cases, an explicit cost, and scope limitations, the description provides everything an agent needs to select and invoke the tool correctly. The combination of usage triggers, data provenance, and output summary makes this definition complete for its complexity.

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 schema already documents the single 'iid' parameter with format, example, and leading-zero behavior. The description repeats this information without adding significant new semantic detail. Given the high schema coverage, score 3 is the appropriate baseline.

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 a specific verb and resource: 'Resolve a Swiss BC-Nummer / IID (1 to 5 digits) into the underlying institution.' It clearly differentiates itself from siblings like lookup_bic by emphasizing payment-rail participation, QR-IID allocation, and 'not just a name lookup.' An agent can accurately identify when this tool applies without opening the 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?

The 'USE WHEN' section provides concrete triggering scenarios: BC-Nummer/IID mentions, CH/LI IBAN clearing codes, Swiss instant transfer routing, QR-IID resolution, and institution classification. It also adds a geographic exclusion ('Only relevant for CH and LI accounts'). It does not explicitly name a sibling alternative like lookup_bic, so it stops short of the full when-not/alternative guidance.

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