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

Annotations already provide readOnlyHint, destructiveHint, idempotentHint. The description adds the scope (700K+ documents) but does not disclose additional behavioral traits like pagination limits or result truncation. Given annotations cover the safety profile, a 3 is appropriate.

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 compact with three sentences covering scope, examples, and differentiation. It is front-loaded and efficient, though the mention of non-existent parameters slightly detracts from clarity.

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 search tool with a full output schema, the description adequately covers scope and filters. It does not explain pagination or sorting (provided in schema) but is complete enough for typical use. The missing filter parameters reduce completeness slightly.

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 100% with detailed parameter descriptions. However, the description mentions filtering by content type, organisation, and topic, which are not present as separate parameters in the schema. This introduces ambiguity and potentially misleads users, failing to add value beyond the schema.

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 the tool performs full-text search across all 700K+ GOV.UK documents, lists document types, and explicitly distinguishes it from UK FSA. This provides a specific verb (search) and resource (GOV.UK documents) and differentiates from sibling tools via context.

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 gives clear context for when to use (search across all government publications) and distinguishes from UK FSA. However, it does not explicitly guide against using it for other GOV.UK tools like 'govuk.content.fetch' or mention prerequisites, which would push it to a 5.

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