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

Annotations already declare destructive=true, readOnly=false, and non-idempotent, so the safety profile is carried by structured data. The description adds genuinely new context — that only 'known' cache plugins plus the object cache are affected, and that the plugin state is read first — but it omits consequences such as downtime, whether page/asset caches are purged, and whether the operation can partially fail.

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?

One sentence, front-loaded with the action and scope, with no filler. It could be marginally tighter by folding the state-read clause into a behavioral note rather than the main sentence.

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 destructive, non-idempotent one-parameter mutation with no output schema, the definition is minimally adequate: scope and pre-read behavior are stated. It leaves out what the agent needs to reason about after a destructive call — what is invalidated, whether repeated invocation is safe, and what the response reports.

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?

With a single parameter at 100% schema coverage, the schema already explains site_id, its origin from list_sites, and the explicit prohibition on URLs or post IDs. The description adds nothing further about the parameter, so baseline 3 applies.

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 and resource: clears cache plugins and the WordPress object cache. It does not name or contrast itself with nearby siblings such as wp_list_cache_plugins, wp_elementor_flush_css, or the transient/session clearing tools, so the agent must infer the boundary from names alone.

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?

There is no when-to-use or when-not-to-use guidance and no named alternative. The clause 'after reading the current cache-plugin state first' describes internal sequencing, not the conditions under which an agent should choose this tool over the flush_css or clear_transients siblings.

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