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

Annotations only declare it is a non-read-only, non-destructive, non-idempotent closed-world write. The description goes well beyond that: it names the account the artifacts land in, caps output at three distinct designs, warns the work takes a few minutes, and explains the asynchronous contract (returns the project id immediately). It stops short of saying a repeat call spawns another project or what happens if the same prompt is resubmitted.

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 sentences, front-loaded with the action, then the input expectation, then the async behavior. No filler and nothing buried; the timing caveat arrives right where an agent needs it.

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 no output schema, the description correctly compensates by explaining that the return value is the project id and that designs arrive later. The one gap is the follow-up path: an agent holding the id is not told to use get_designs to check progress once the few minutes elapse.

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 there is only one parameter, so the baseline applies. The description restates the prompt content in slightly different words ('what it is, who it is for, what it offers, and any look') but adds no syntax, length, or formatting guidance beyond the schema's minLength/maxLength.

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 ('Designs a website or web app from a description') plus the scope of what the description must contain. It is clearly distinguishable in behavior from get_designs/get_design_html (read) and edit_design (modify), but it never names those siblings to make the boundary explicit.

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?

Usage is implied: call this when someone wants a new site built from a prose description, and the description tells you what to put in that prose. There is no explicit when-not guidance, no mention of edit_design as the alternative for refining an existing design, and no stated prerequisites.

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