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

Beyond the annotations (readOnlyHint=false, destructiveHint=false), the description discloses that a newly created site starts empty and remains so until files are published. This is useful runtime behavior context that is not present in the schema or 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?

Two compact sentences with no filler. The core action is front-loaded, and the second sentence adds lifecycle context while referencing exact sibling tools.

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 creation tool with one optional parameter, the description is nearly complete: it states the action, the subdomain context, and the empty initial state. The main absence is any mention of what the successful response returns (e.g., site URL or id), though that is not required by the invocation itself.

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%, and the description itself does not add parameter details beyond what the schema already states. The main text only reinforces that the site is created on a subdomain, which is already implied by the schema's 'Desired subdomain' field, so the baseline 3 applies.

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 and resource, 'Create a new site,' and adds the key qualifier 'on a free subdomain.' It also distinguishes creation from content-publishing tools by noting that the site stays empty until files are published with write_files or start_upload.

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?

It communicates the intended workflow by naming write_files and start_upload as the follow-up actions that populate the site. It does not explicitly state when not to use create_site or compare it to list_sites/delete_site, but the sequential guidance is clear.

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