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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, covering the safety profile, so the bar is lower. The description adds that the call is 'signed' and returns an audit-ready report plus an XDR-1 receipt, but gives no detail on what signing entails, auth requirements, or failure modes for a 4-input screen.

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?

A single front-loaded sentence with a colon that immediately names the operation, followed by benefit/context. Dense but efficient; the marketing framing ('Saves 50%', 'Clearing Shield') is padding rather than information.

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, and annotations cover safety and idempotency. The description conveys purpose, context and output artifacts, though it leaves the all-optional-parameter case and any prerequisites unaddressed.

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% and every parameter carries its own description, so the schema does the heavy lifting. The description adds nothing about parameter format, combinations, or what happens when none of the entirely optional fields are supplied, so it cannot exceed the 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?

States a specific verb and resource: screens four named vendor identifiers (IBAN, LEI, VAT, UK company number) in one call. It implicitly distinguishes itself from the individual *_check siblings via 'Saves 50% vs individual checks', but never names them, so the differentiation is inferential rather than explicit.

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?

Gives a clear usage moment — 'before funds move' and 'to defend against invoice fraud' — which tells the agent when this screening is warranted. It does not state when NOT to use it or explicitly name the single-check alternatives an agent should prefer for narrow needs.

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