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

With no annotations, the description carries the full behavioral burden. It usefully discloses that exact title matches are preferred and ambiguous or fuzzy-only matches are flagged for review, plus the important limitation that this is evidence assembly rather than verification or clearance. However, it omits operational details such as read-only safety, authentication, rate limits, and how matches or flags are represented in the response.

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 definition is three dense sentences with no wasted wording. It front-loads what the tool does, then explains input modes and ends with clear scope limitations.

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 five-parameter evidence-assembly tool with no annotations and no output schema, the description covers selection and input routing well. It does not describe the return shape of the evidence pack, the structure of candidate profiles, or how GLEIF and sanctions evidence are presented, which leaves meaningful gaps for an agent relying on the description alone.

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%, so all five parameters are already documented in the input schema. The description reinforces the company_number direct-lookup path versus company_name/postcode resolution and mentions optional GLEIF and sanctions evidence, but adds only modest semantic value beyond the schema's own descriptions and anyOf constraint.

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 states a specific verb and resource: assemble a Companies House candidate and profile with optional GLEIF and sanctions evidence in one call. It clearly distinguishes this bundled evidence-pack tool from narrower siblings such as uk_company_search, lei_lookup, and sanctions_screen.

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 explains the two input modes: company number for direct lookup, or company name plus optional postcode for candidate resolution. It also sets boundaries with 'not identity verification, a KYB decision, or sanctions clearance,' though it does not explicitly name sibling alternatives to use instead for narrower tasks.

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