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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description adds genuinely useful behavioral context beyond that: it discloses the shape of the result (counts of published entities and a last-modified timestamp), which matters since no output schema exists.

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 front-loaded sentence that names the action and the returned data with no filler. Every clause contributes information.

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 zero-parameter, no-output-schema tool, the description covers enough to call it correctly and even substitutes for the missing output schema by naming what is returned. It could be slightly stronger by noting counts are scoped to published items only, but nothing critical is missing.

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 documentation burden; the baseline of 4 applies. The description also notes the implicit 'published' scope of the counts, which is the only filtering-like semantics relevant here.

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?

States a specific verb ('Get the number of') plus the exact resources counted (published restaurants, places, categories) and an extra returned field (last change time). It is clear on its own, but it never distinguishes itself from siblings like list_categories or list_places, which return the entities this tool merely counts.

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 a summary/count endpoint rather than an enumeration one. There is no explicit when-to-use statement and no mention of alternatives such as the list_* siblings when the agent actually needs the underlying records rather than counts.

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