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

With readOnlyHint true, the annotation already signals no side effects. The description adds the nuance that the listing reflects files 'currently' on the resource-moderate but does not disclose potential caveats such as pagination, ordering, or permissions. Overall it is consistent but provides only a small behavioral addition beyond the annotation.

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?

The description is a single, front-loaded sentence with no filler. It states the action, the target, and the key parameter constraint in a compact manner.

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 two parameters and no output schema, the description covers the essential call semantics: what it liststemp, which parameters identify what, and that exactly one parameter is required. It could mention return format or item types, but the description is adequate for a read-only list operation.

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 description maps siteId to a site and previewId to a preview, and explicitly states that exactly one must be passed. This adds crucial meaning not present in the schema, where siteId has no description and no mutual-exclusivity constraint is declared.

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 uses a specific verb ('List') and a clear resource ('files currently on a site or a preview'). It clearly distinguishes this from sibling tools like list_sites, list_previews, and read_site_file by indicating it returns files, not the resources themselves.

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 clear context: this tool lists files, and it instructs the agent to 'pass exactly one' of siteId or previewId. It does not explicitly contrast with sibling tools, but the resource type ('files') makes the appropriate use case obvious enough.

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