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

Annotations already declare readOnlyHint/destructiveHint=false, but the description adds substantive behavior: the full return shape, the meaning of status ('active' vs 'inactive' for wp_inactive_widgets and why those widgets persist), and a distinct empty-result shape with a hint for block themes. It loses a point because the permission sentence is truncated ('Requires the edit_theme_options c…'), leaving the auth requirement incomplete.

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-loaded with purpose and return shape, and nearly every clause carries information (return keys, inactive semantics, block-theme fallback, next steps). It is dense and slightly run-on, and the trailing 'Through Royally: its server marks it read-only…' is boilerplate plus a truncated permission clause.

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 fully carries the return contract: the sidebars array fields, total, the status values, and the alternate { sidebars: [], total: 0, hint } shape. An agent can both decide and call correctly without further documentation.

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%, so baseline would be 3, but the description goes beyond the schema by spelling out that include_markup returns class/before_widget/after_widget/before_title/after_title and the edge case that these are empty strings for wp_inactive_widgets. That edge case is the kind of detail the schema does not convey.

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?

Opens with a specific verb and resource: 'Lists the widget areas (sidebars) of a classic theme — sidebars, footers and other areas the theme registers.' It also explicitly scopes itself to classic themes, which separates it from the block-theme template tools (wp_list_templates / wp_get_template) and from wp_list_widgets, which surfaces widget settings rather than areas.

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?

Gives the block-theme escape hatch explicitly ('When the theme has no widget areas — a block theme — … the hint points to wp_list_templates / wp_get_template') and names concrete next-step siblings (wp_list_widgets, wp_create_widget, wp_update_widget). It also states the capability prerequisite (edit_theme_options), so the agent knows the precondition for use.

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