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

Annotations only say it is a non-readonly, non-destructive, non-idempotent open-world write. The description adds real behavioural context the annotations cannot: the design is copied rather than generated, it consumes no generation credits, it occupies one draft-site slot under the plan, and it completes in about two minutes. That is exactly the cost/side-effect information an agent needs before invoking a site-creating mutation.

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?

Purpose and the key differentiator ('design is copied, not generated') are front-loaded, and the cost/time facts plus the input recipe follow in a logical order. It is slightly dense in a single long first sentence, but no sentence is 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 mutating, open-world tool with a nested object parameter and no output schema, the description covers prerequisites, cost, slot consumption and timing. It stops short of saying what comes back (site id, preview URL) or what happens if the pack intake is incomplete, which would fully close the loop.

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 the baseline is 3, but the description adds genuine meaning: pack_slug must come from list_packs, and pack_intake holds answers keyed by question id with required questions mandatory. The only untouched parameter is user_goal, which the schema already documents thoroughly.

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 and resource ('set up ... ready-made business') and defines what it produces: a whole working site with listings, flows and pages already in place. It explicitly separates itself from list_packs (the source of the pack) and from brief-based site generation, so an agent can place it among the many create_*/clone_site siblings without opening the 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 concrete preconditions: get the pack from list_packs, send its slug, the business name, and answers keyed by question id with required ones filled. It also excludes the neighbouring case ('to generate a new site from a brief instead, that is a different flow') but does not name that alternative tool (create_site / create_site_from_design), leaving the agent to find it.

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