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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered structurally. The description adds a little beyond that by telling the agent the response is counts plus a last-changed indicator, which is useful context, but it says nothing about format, units, or scoping of 'published'.

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?

A single sentence that front-loads the operation and enumerates exactly what is returned, with no filler or redundant restatement of the tool name.

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?

With no output schema, the description carries the burden of describing the return payload, and it does so by naming the three counted entity types and the last-changed timestamp. It stops short of specifying the shape of that timestamp or whether counts are global, which is a minor remaining gap for a zero-parameter summary tool.

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 tool takes zero parameters, so there is no parameter semantics to explain and the schema coverage is 100%. The description correctly adds no parameter discussion, leaving the baseline for parameter-free tools.

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 verb ('Get the number of') and enumerates the exact resources counted (published abatement contractors, places, categories) plus a data-freshness timestamp. This clearly separates it from listing tools like list_places or list_categories, though it does not explicitly name any sibling as an alternative.

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?

Usage is only implied: an agent can infer this is the right tool when it needs aggregate counts or a last-updated check rather than entity records. There is no explicit 'use this when' statement and no mention of alternatives such as the list_* or search_listings tools.

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