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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds useful behavioral nuance beyond annotations by warning that calling with pageId alone fails for anonymous demo pages and that editToken must come from the create result.

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?

Three sentences, front-loaded with the core behavior, and every sentence adds value. The key alternative and the token requirement are presented clearly with no filler.

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 tool with a robust annotation set and an output schema, the description covers all essential decision-making information: what it returns, when it is unnecessary, when it requires an extra token, and what failure mode to expect.

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%, so the schema already documents both parameters. The description adds meaningful context by clarifying the consequence of omitting editToken on anonymous demo pages, which goes beyond the schema's 'Required for anonymous demo pages' phrasing.

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 action and resource: 'Return the current preview URL for a page.' It also distinguishes itself from page_create and page_create_from_brief by noting those already return a previewUrl, making the tool's niche clear.

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 explicitly says 'You usually do not need this' and names the alternatives that already return a previewUrl. It also provides a specific condition for when this tool is required: anonymous demo pages must pass the editToken from the create result.

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