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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, so the safety profile is covered. Beyond that the description adds real behavioural context: the upstream source, that individuals are never named among lenders, that both fixed and floating charges are covered, and that a total/outstanding split is returned. It omits pagination, rate limits, and behaviour for companies with no charges.

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, purpose front-loaded before the field enumeration, with no filler. The second sentence is a dense list but each item carries distinct information about the returned data.

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, the description carries the return-value burden and does so reasonably: totals, outstanding amounts, lenders, security type (fixed/floating), what is charged over, and latest creation date. Gaps are minor (shape of the response, empty-result behaviour) given the single-parameter, read-only nature of the tool.

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?

Only one parameter (company), and schema description coverage is 100% ('A company number or name'), so the schema fully documents it. The description adds no format or disambiguation detail beyond implying the company identifies the charges; 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 clear verb+resource ('a company's registered charges') and names the data source (Companies House register of charges), so the agent knows exactly what entity is being retrieved. It doesn't differentiate from nearest siblings such as registers or public_record, but the subject matter is unambiguous.

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?

There is no explicit when-to-use, when-not-to-use, or alternative tool guidance; the use case (assessing secured borrowing) is only inferable from the field list. An agent gets no help deciding between this and registers or public_record.

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