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

Annotations already declare write, open-world, non-idempotent, non-destructive behavior. The description adds genuinely useful context beyond that: which content is auto-filled from the store listing versus which pages start empty (privacy policy, terms, account deletion, support), and that pages must be filled afterward. It stops short of saying what happens on subdomain collision or how long the build takes, keeping it at a 4.

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 tight sentences with the creation scope front-loaded, followed by the content-completeness caveat and the prerequisite check. No filler, every clause carries information.

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 write tool with no output schema, the description covers what gets created, what is auto-populated, what is left empty, and the required prior check. A brief note on collision behavior or return value would make it fully complete, but nothing critical to correct invocation 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 all five parameters, including the enum values for store and theme, are already documented. The description restates the subdomain format already present in the schema and adds no meaning for app, store, country, or theme. Baseline 3 is appropriate when structured data does the heavy lifting.

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?

States a specific verb+resource ('Create a website for a published app') and immediately scopes it to the generated subdomain address and store-listing-sourced content. An agent can distinguish it from set_page, update_site, or refresh_site_from_store without opening a schema.

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?

Gives explicit prerequisites and alternatives: 'Check the address with check_subdomain first' and 'write them with set_page' for the empty legal pages. This tells the agent both the ordering constraint and which sibling handles the follow-up work.

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