ons_data_dimensions

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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, covering the safety profile. The description adds only the 'live API' context, implying fresh or uncached results, but does not disclose other behavioral traits such as how the optional dimension parameter affects the response.

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 a single front-loaded sentence with no filler. Every word contributes to identifying the operation and resource.

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 simple read-only metadata tool, the annotations and existing output schema reduce the burden. However, the description still leaves gaps: it does not explain how to obtain valid dataset/edition/version values, nor how this tool fits into the broader ONS data workflow alongside sibling tools. This is adequate but not 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 only 20%: only 'dimension' has a schema description. The tool description does not explain the required dataset, edition, and version parameters at all, nor how they scope the dimension list. With coverage this low, the description was expected to compensate and does not.

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 ('List') and a precise resource ('ONS observation dimensions'), making the tool's job immediately clear. The name and wording distinguish it from sibling tools like ons_data_editions, ons_data_versions, and ons_data_get_observation without ambiguity.

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 no guidance on when to use this tool versus the many related ONS tools, such as ons_data_query, ons_data_get_observation, ons_data_editions, or ons_data_versions. Any usage context is only implied by the tool name, not stated.

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