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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=true, so 'read-only, runs straight away' mostly restates structured data. The one genuinely additive piece is the enumeration of returned fields, which matters because there is no output schema; no pagination, ordering, or empty-state behavior is described.

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?

Returned fields and the routing hint are front-loaded in three short sentences with no bloat. The trailing 'read-only, runs straight away' clause largely duplicates the annotations, so one sentence fails the 'earns its place' test.

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-required-parameter read tool with no output schema, the description covers what is returned and why to call it. The remaining gap is minor: it does not say what an empty result means (e.g., a theme with no registered widget areas).

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 100% with a single optional site_id whose enum already pins the target site, so the schema does the heavy lifting. The description's parenthetical '(site: demo.royalplugins.com)' merely echoes the enum value and adds no new semantics such as defaulting behavior.

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?

Names a specific verb and resource ('List registered sidebars (widget areas) on the active theme') and even enumerates the returned fields (IDs, names, description, status). An agent can immediately distinguish this from wp_get_widgets or wp_list_widget_types without opening a schema.

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 states the use case: 'discover sidebar IDs before calling wp_get_widgets or wp_update_widget', which routes the agent to the correct follow-up tools. It does not state when not to use it or name a lookalike read tool as an alternative, keeping it just below a 5.

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