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

Goes well beyond the readOnly/idempotent annotations: it discloses data provenance and daily refresh, a deliberate field-coverage restriction (no officers/PSC, address lines dropped for locality/postcode), per-call credit cost, and a concrete unauthenticated quota (5-row preview, 20 calls/day). Those are exactly the operational facts an agent needs before calling.

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?

Three tightly packed sentences, front-loaded with what the tool returns, then constraints, then cost. Dense but every clause carries operative information; the only mild clutter is the pricing/quota sentence, which is nevertheless decision-relevant.

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, 12-parameter, no-output-schema listing tool, the description covers provenance, privacy posture, cost and rate limits well but leaves half the parameters semantically opaque. An agent can invoke it, yet cannot confidently construct filter values like status or company_type without guessing.

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 0% across 12 parameters, so the description carries the full burden and mostly doesn't: it explains only that q searches all text fields and that filters AND together. The meaning of status, company, company_type, sic_codes, locality/postal_code, or pagination via page/per_page is never clarified (e.g., whether 'company' is a name or number match).

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 concrete resource (newest companies on the UK register from Companies House) plus the field set returned, so the agent knows exactly what this returns. It implicitly separates itself from query_uk_company_profiles by emphasising 'newest' incorporations, but never names that sibling or any other, so differentiation requires inference.

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?

It gives clear context for calling: use it for recent incorporations, combine filters with AND, and use q for full-text search. The 'Blind Mode' clause also signals when-not (officer/PSC questions belong elsewhere), though it never explicitly points to the right alternative tool.

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