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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds value by disclosing the return metadata (titles, URL paths, publication timestamps) and the degree of scoping. It does not mention pagination or rate limits, but these are less critical given the annotations.

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 with zero fluff: the action, scope, and return values are front-loaded. Every clause earns its place, and no redundant information is present.

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 complexity (4 parameters, no schema descriptions, output schema present), the description covers the core search behavior and return fields but omits pagination semantics for count/start. An agent might struggle to construct a correct paginated request without additional inference. Annotations and the output schema help, but the description could have been more complete.

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%, so the description must compensate. It explains the 'query' parameter as free text and 'filter_format' as a document format, but gives no meaning for 'count' or 'start' (likely pagination). The examples in the schema hint at their use, but the description itself leaves those two parameters under-specified. Partial compensation only.

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 names a specific verb ('Search'), a clear resource ('everything published on GOV.UK'), and enumerates content types (guidance, forms, statistics, etc.). It also states the optional narrowing by document format, which distinguishes it from siblings like search_autocomplete and search_within by scope. An agent can tell this is the broadest search tool.

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 provides clear context for when to use the tool: when searching all GOV.UK published content, optionally filtered by document format. It does not explicitly exclude or point to siblings like search_autocomplete or search_within, but the scope makes the intended use evident. No alternatives are named, so it stops short of a 5.

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