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

Goes well beyond the annotations: discloses the 12-hour rate-limited remote check against wordpress.org, the `package_available=false` case for licence-gated plugins, the required update_plugins capability, DISALLOW_FILE_MODS and multisite super-admin restrictions. The 'refreshes update data first' note also explains why idempotentHint is false.

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?

Front-loads the purpose, then the refresh/caveat detail, then the return shape, then capability gating. Dense parentheticals make it long, but nearly every clause carries decision-relevant information; only the Royally read-only note is arguably redundant with the annotations.

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?

No output schema exists, and the description supplies a full field-by-field return contract including total and last_checked semantics. Capability prerequisites and failure modes are covered, so an agent has everything needed to call and interpret it.

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 coverage is 100% and site_id is fully documented in the schema, so the baseline applies. The description's 'No parameters' is slightly imprecise given the required-routing site_id exists, but it adds no harm and no extra meaning for the single parameter.

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 ('Lists installed plugins that have a newer version available') and anchors it to the familiar Dashboard → Updates view. It is clearly distinguishable from wp_list_plugins (all installed plugins) and wp_update_plugin (the action to install).

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?

Explicitly routes the agent to the next step ('Pass an entry's `plugin` to wp_update_plugin'), which is strong guidance. It doesn't contrast against near-neighbours like fleet__check_updates_pending or explain when you would not need this, so it falls short of a 5.

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