company_search

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

No annotations are present, so the description carries the full burden. It clarifies the tool is a search that returns matches, implying read-only behavior. While it doesn't elaborate on rate limits or pagination, for a simple search this is sufficient and not misleading.

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 extremely concise at two sentences, with no wasted words. The key action and alternative are front-loaded, making it easy for an agent to quickly understand and act.

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 the tool's simplicity (one required parameter, no output schema, no annotations), the description is complete. It explains the search function, provides example inputs, and directs to an alternative for specific lookups. No additional details are needed for correct invocation.

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?

The single parameter 'query' is described in the schema with a clear description and example values ('Tesco', 'Rightmove plc') in the tool description, adding concrete context beyond the schema's minimal description. This helps the agent form valid 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?

The description clearly states 'Search Companies House by company name' and specifies it returns a list of matches, making the purpose unambiguous. It also distinguishes from the sibling tool company_profile by hinting at an alternative resource lookup.

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 explicitly tells when to use the tool (search by name) and provides a clear alternative for direct company number lookup via a resource, including an example. This guides the agent to choose correctly between siblings.

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