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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavior: the output is a per-mesh-block percentage bounded 0-100, near-empty blocks are filtered out of the result, and no geometry is included. That filtering note is especially valuable because an agent could otherwise read a missing block as zero.

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 measure and unit are front-loaded, followed by the filtering rule and the companion endpoints, with essentially no filler. The opening clause about where the layer appears in the UI report is the least useful sentence for an agent but is short and sets context.

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 single-parameter, no-output-schema tool, the description covers what is returned (values only, percent scale), what is excluded (near-empty blocks), and what must be fetched elsewhere for polygons. The one gap is the input format for suburb_name, which is neither documented here nor in the schema.

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% for the single required parameter suburb_name, and the description never explains how to express it (plain name versus name+state, casing, or whether to resolve it first via geocode_suburb). With only the phrase 'in the suburb' the agent must guess the identifier format for the one input that matters.

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 artifact (the 'Single parents' map layer in the Demographics section) and a precise measure: single-parent families as a share of families, percent 0-100, for every mesh block in a suburb. It also distinguishes itself from related resources by stating that the suburb-level figure lives at /demographics/single-parents and the polygons at /shapes/mesh-blocks, so an agent can tell it apart from suburbs_demographics_single_parents and the shapes tools.

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?

It gives operative context for use: this returns only values, so you must pair it with /shapes/mesh-blocks (suburbs_shapes_mesh_blocks) for geometry, and the suburb-summary number is a different endpoint. There is no explicit when-not guidance, but the composition constraint is clear enough to route an agent correctly.

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