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

With no annotations provided, the description carries the full burden and does well: it discloses 'Blind Mode' limitations (officer and PSC data never ingested, address lines dropped), refresh frequency ('refreshed daily'), filter semantics (AND combination, q searches all text), and cost ('Costs 1 credit(s) per call'). This gives an agent a solid understanding of what to expect, though it stops short of explaining response shape or auth requirements.

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?

The description is concise and well-structured: it opens with the core purpose, then states key limitations, then filtering behavior, then cost. Every sentence adds value, and the most important information is front-loaded.

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?

Given 12 parameters, no output schema, and no annotations, the description is incomplete. It lacks parameter-level documentation, response format, and any examples. While it covers purpose and high-level behavior, an agent cannot correctly construct a query without understanding what each parameter means, so it falls short of completeness.

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%, so the description must compensate. It only mentions that 'q searches all text fields' and that filters combine with AND, but does not explain the purpose of the other 11 parameters (e.g., status, company, locality, postal_code, incorporated_on_after). This is a critical gap for a tool with many optional parameters.

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 clearly identifies the resource (newest UK companies), the source (Companies House API), and the specific data fields returned (name, number, type, SIC codes, incorporation date, registered-office area). This effectively distinguishes it from sibling tools focused on other UK datasets (insolvency, planning, etc.).

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 implies usage for UK company data but does not explicitly compare to alternatives or state when not to use this tool. It provides operational details like 'Filters combine with AND' and 'q searches all text fields', but lacks explicit routing guidance versus siblings. The context is clear enough for a domain-specific query, but no exclusions are mentioned.

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