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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds context annotations cannot: the per-line verdict vocabulary (release, review, hold), the specific risk classes checked, and a hard quota (25 here, 100 with an API key over HTTP). It does not say what happens on malformed input or how the verdict should gate a real payment run, so it is strong but not exhaustive.

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 with cost and use case, then input format, then outputs, then limits — a sensible priority order with almost no filler. The long risk-class enumeration is dense and slightly run-on, but every item is substantive.

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?

For a two-parameter, non-destructive read tool with no output schema, the description covers purpose, inputs, the shape of the result (per-line release/review/hold) and quota limits. Nothing an agent needs to invoke it correctly is missing.

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 both parameters are already documented; the description still adds value by specifying the concrete encodings (SEPA pain.001 XML, or CSV carrying payee name and IBAN) and by framing `previous` as an optional accuracy booster ('best'). The relative importance of the optional parameter is meaning the schema alone does not convey.

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 ('check a payment file before it goes to the bank') plus the accepted input formats, which clearly distinguishes it from single-item siblings like iban_check, eu_sanctions_screen and x402_payee_check. An agent can tell this is a whole-file pre-payment screening tool 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?

'Use before a payment run is sent to the bank' gives explicit timing and intent, and it recommends supplying 'last run's file or a vendor list as previous'. It never names an alternative sibling or a when-not condition, so it stops short of full routing guidance.

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