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

Annotations already declare the tool as read-only, idempotent, and non-destructive. The description adds value by specifying the exact return content (title, document type, publication dates, section list) and explicitly what it does not do (return page body), steering users to sibling tools. This is useful behavioral context beyond the annotation flags.

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 three sentences: purpose, return values, and alternative tools. It is concise, front-loaded with the key verb and resource, and every sentence adds necessary information without waste.

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 single parameter, informative schema, and existing output schema, the description fully covers what the tool does, what it returns, and how it relates to sibling tools. The agent has enough context to select and invoke it correctly without needing further detail.

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 input schema provides 100% coverage with a clear description and example for base_path. The tool description itself does not add parameter semantics beyond what the schema already provides, so the baseline of 3 for high schema coverage 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?

The description uses a specific verb ('Get') and resource ('GOV.UK page'), and clearly states what is returned (metadata and navigable section index). It explicitly distinguishes from sibling tools by noting that govuk_get_section reads a section body and govuk_grep_content searches within the page.

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 explicit guidance on when to use this tool vs alternatives: 'Use govuk_get_section to read the body of a specific section, or govuk_grep_content to search within the page body.' This clearly indicates the tool's scope (metadata/index) and points to alternatives for other use cases.

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