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

Annotations already cover read-only/idempotent safety, but the description adds real behavioral context: the edit context, how classic vs block widget payloads differ (instance settings vs instance.raw.content plus a parsed blocks field), and that inactive widgets have rendered:"" and produce no front-end output. This goes well beyond the annotations.

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 the core action, then structured details on payload shape and filtering. Dense but every sentence carries information; slightly long but not padded.

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 read-only list tool with full schema coverage and no output schema, the description covers what is returned, how classic vs block widgets differ, and all parameter edge cases. Nothing an agent needs to call it correctly 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?

Schema coverage is 100%, so baseline is 3, but the description meaningfully enriches the sidebar parameter's semantics (all-sidebars default, inactive widget inclusion, empty-array-on-invalid behavior) beyond the terse schema text.

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+resource ('List widget instances') and immediately distinguishes scope by explaining the edit-context endpoint returns both rendered output and full instance payload for classic and block widgets. An agent can tell it apart from siblings like wp_get_sidebars and mutation tools such as wp_update_widget.

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 two usage modes: omit sidebar to get all sidebars including wp_inactive_widgets, or pass a specific sidebar ID (with a pointer to wp_get_sidebars for discovery). It even notes the edge-case behavior of a non-existent sidebar returning an empty array rather than an error.

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