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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so safety is covered and the bar is lower. The description usefully adds the external data source (Companies House) and geographic scope, but says nothing about what happens with zero or multiple matches, or about external-register rate limits, which matters for an openWorld tool.

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?

A single front-loaded sentence with no filler. It is efficient, though the brevity comes at the cost of the missing behaviors noted elsewhere rather than from ruthless prioritization.

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 one-parameter read tool with no output schema and full annotation coverage, the essentials are nearly there. The critical gap is return shape: 'Finds a company' does not reveal whether the agent gets one company or a list of candidates to disambiguate, which directly affects how it should call and follow up.

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% for the single required parameter, so the description must carry the meaning. 'By name' merely restates the schema property name 'name'; it does not say whether partial or fuzzy names are accepted, whether it must be an exact registered name, or how the 160-character limit relates to real inputs.

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 and resource: 'Finds a UK company on Companies House by name.' The scope (UK register, name-keyed lookup) distinguishes it clearly from siblings like save_company_profile or search_contract_awards, though no sibling is named explicitly.

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?

'for Winquill's setup' implies this belongs to the onboarding flow, so an agent can infer when it is relevant. However, it never says what to do when the lookup fails or is ambiguous, nor points to the natural follow-on tool (save_company_profile) that consumes the result.

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