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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint false, establishing it as a safe read operation. The description adds valuable context about the data source (api.ukhsa-dashboard.data.gov.uk), the open government licence, and that no auth is required. It also describes the drill-down behavior, going beyond annotations without contradicting them.

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 concise (three sentences), front-loads the purpose and hierarchy, and efficiently covers usage, data source, and licensing. Every sentence earns its place, with no redundant fluff.

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?

The description is complete for a browse tool: it explains the hierarchical navigation, how to invoke it with no params and with successive params, and the ultimate goal of reaching a metric name. It also notes the data source and license. The only minor gap is a slight naming mismatch (ukhsa-dashboard.metric_data vs the actual sibling ukhsa-dashboard.metrics.data) and no mention of pagination, but these are non-critical for a catalog browse.

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 schema provides 100% coverage of parameters, each with a description, examples, and dependency requirements. The description reiterates the drill-down pattern but does not add significant meaning beyond what the schema already states. Per the rubric, with high schema coverage the baseline is 3, and the description does not elevate it further.

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 browses the UKHSA data dashboard drill-down catalog, listing the hierarchy (themes -> sub_themes -> topics -> geography_types -> geographies -> metrics). It also distinguishes itself from the data retrieval tool by stating it is used to reach a metric name for ukhsa-dashboard.metric_data. The purpose is specific and unambiguous.

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 explicit usage instructions: call with no params to list themes, then pass increasingly specific params to drill down one level at a time. It also clarifies the endpoint goal (reaching a metric name) and mentions that this is the precursor to fetching data with ukhsa-dashboard.metric_data. This fully guides the agent on when and how to use it.

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