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

Annotations already provide readOnlyHint, openWorldHint, and idempotentHint. The description adds useful behavior beyond that: it is a signed call, checksums each identifier, produces a single verdict and receipt, and bundles multiple checks. This gives the agent a clear sense of what happens when invoked.

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?

Two tight sentences with no filler. The core purpose and the main differentiator (one call, one verdict, one receipt, half price) are front-loaded, and every clause adds value.

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 bundled validation tool with an output schema and safety annotations, the description covers the key context: what identifiers are involved, what the user gets (verdict + receipt), and the economic benefit. It could be more explicit about when to prefer this over individual sibling checks, but overall it is adequately complete.

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 each parameter is already documented by name and optionality. The description adds only high-level context ('each checksummed, one verdict') without providing additional per-parameter meaning beyond the schema, so the baseline of 3 is appropriate.

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 names a specific verb ('Screen'), a specific resource ('a vendor's identifiers'), and the exact set of identifiers (IBAN, LEI, VAT, UK company number). It also distinguishes itself from the individual check tools by highlighting the bundled, single-call nature and the price advantage.

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 clearly implies when to use this tool: when multiple vendor identifiers need to be screened in one call rather than through separate checks. The phrase 'Half the price of four single checks' communicates the trade-off versus alternatives, though it does not explicitly list alternative tool names or state when NOT to use it.

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