List widget areas

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

Annotations declare readOnlyHint=true and destructiveHint=false, and the description adds value beyond that by explaining that in block themes the tool may return no classic sidebars and that this is expected, not an error. It also clarifies that the output includes widgets placed in each area. These are behavioral details not present in the annotations, making the tool's behavior more predictable.

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?

Two sentences with no waste. The primary action is stated first, followed by a crucial edge-case note. Every word earns its place, and the structure is immediately scannable.

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 simple read-only list tool with one optional parameter, the description covers what is returned (widget areas and their widgets), manages the common block-theme expectation, and is consistent with the safety annotations. There is no output schema, but the description sufficiently describes the result shape. 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?

The only parameter, site_id, is fully documented in the schema (coverage 100%), including its optionality, default behavior, and reference to list_sites for valid ids. The tool description adds no additional meaning to the parameter, so it does not exceed the baseline of 3 for high schema coverage.

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?

The description states a specific verb ('List'), a clear resource ('the theme's widget areas (sidebars)'), and what it returns ('the widgets currently placed in each'). It also distinguishes itself from the sibling list_widgets by focusing on widget areas and their contents, and it preempts a common confusion (block themes have no classic sidebars). This is precise and unambiguous.

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?

The description gives contextual guidance by noting that block themes typically have no classic sidebars, which sets expectations. However, it does not explicitly state when to use this tool over the sibling list_widgets or any other tool, nor does it mention exclusions or alternatives. The usage context is implied but not made explicit.

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