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

Annotations already declare read-only, idempotent, open-world behavior, so the safety profile is covered. The description adds genuine context beyond that: the data sources, the fallback matching logic (company number first, exact registered name otherwise), and a preview of returned content (count, notified value, top buyers, latest awards) in the absence of an output schema.

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 dense sentences with the resource and scope front-loaded, followed by sources, return contents, and matching rule. No filler, though the second sentence is slightly packed with three distinct facts.

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 usefully summarizes what comes back, and annotations cover the safety profile, so the core is complete. Remaining gaps are the undocumented 'months' parameter and any default time window or result-count behavior.

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 coverage is 50%: 'company' is documented and the description usefully extends it with the number-vs-exact-name matching rule. However, 'months' has an empty schema description and is never mentioned in the description, leaving the time-window control entirely unexplained to the agent.

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 resource and scope ('Public-sector contracts a UK company has been awarded') and names the underlying data sources (Contracts Finder, Find a Tender award notices). An agent can tell this apart from generic siblings like company_search or public_record, though no sibling is named explicitly to sharpen the boundary.

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 when-to-use guidance, no exclusions, and no mention of alternatives among the ~19 sibling tools. The matching rule ('by company number where a notice gives one, else by exact registered name') is a behavioral detail, not usage guidance, so the agent must infer the appropriate context.

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