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

With no annotations, the description carries the full burden and does well: it discloses the cost ($0.005 per call), the payment rail (x402, USDC on Base), and response integrity features (provenance chain, Ed25519 attestation). It omits failure behavior for unknown/invalid company numbers and whether payment is strictly required versus optional for a quote.

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. Identity and returned fields come first, and the pricing/provenance sentence follows — front-loaded and every clause carries 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?

With no output schema and no annotations, the description compensates by listing the response fields and the payment/attestation metadata. It is close to complete for a single-record lookup, missing only error/edge-case behavior and identifier format rules.

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 50% and only two params exist. The description usefully clarifies that the required 'id' parameter is a company number, which the schema does not state, but adds nothing about the 12-character limit or accepted formats; the 'payment' param is already explained in its own schema description.

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+resource: 'UK Companies House company record', then enumerates the returned fields (name, status, incorporation date, type, registered office). It is clearly distinguishable from data-summary siblings, though it never explicitly differentiates itself from uk_new_companies_daily, which is the closest sibling.

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 phrase 'by company number' implies the lookup key, but there is no statement of when to use this tool versus uk_new_companies_daily or other UK datasets. No prerequisites, no exclusions, and no mention of the free-quote path that the schema exposes.

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