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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds that the source is official GOV.UK material, which is useful, but says nothing about result format, coverage limits, or how results are ranked. With annotations carrying most of the burden, this is adequate but not rich.

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 first then usage, with no filler. The example list is slightly redundant with the schema but still aids intent matching.

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?

A read-only, two-parameter search tool with full schema coverage and no output schema; the description gives enough to call it correctly. Only minor gaps (what results look like, whether the company parameter scopes the search) keep it from a 5.

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 both parameters and their examples are already documented in the schema. The description repeats the topic examples but adds no new semantics (e.g., query syntax, whether the company param affects scope). 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 specific verb and resource ('Search official GOV.UK tax and business guidance') and reinforces it with concrete topic examples (VAT, corporation tax, dividends). It doesn't explicitly name the nearest siblings (search_tax_facts, list_tax_rules) to distinguish external official guidance from internal stored rules, so it stops short of a 5.

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?

Gives clear triggering conditions ('what does HMRC say about X?', tax rules, filing requirements) which an agent can match against user intent. It offers no explicit when-not-use or named alternative tools, so it's strong context without full routing guidance.

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