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

Annotations only cover the safety profile (readOnlyHint, openWorldHint), so the description carries the response-contract burden — and it does: every requested identifier returns an explicit status (resolved, not_found, invalid_organisation_number) and absence is never signalled by omission. With no output schema this is genuinely useful, though the per-item error taxonomy beyond those three statuses is not elaborated.

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 sentences, zero filler, and the batch capability is front-loaded ahead of the result-contract detail. Every clause adds information an agent needs.

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 read-only batch resolver with a fully documented schema and no output schema, the description covers the essential unknown — how misses are reported. Minor gaps remain (no mention of partial-failure or ordering guarantees), but nothing critical 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 description coverage is 100%: the tier enum, pricing, x402 payment flow and the organisation_numbers pattern/limits are all documented in the schema. The description restates the 50-item cap but adds no format or semantic detail beyond it, so baseline 3 applies.

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 ('Resolve'), resource ('companies') and batching scope ('up to 50 in one call'). The batch framing cleanly distinguishes it from the sibling get_company, so an agent can pick between them without opening either 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 batch size implicitly signals 'use when you have multiple identifiers', but the description never explicitly states when to prefer this over get_company or search_companies, nor any when-not condition. Usage is inferable rather than stated.

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