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

Annotations already cover safety (readOnlyHint=false, openWorldHint=true), but the description adds critical non-obvious traits: the long runtime and client timeout risk, the async alternative, API-key plan/daily limits, and the capped anonymous demo. None of this contradicts the annotations; it meaningfully extends them.

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, each doing distinct work: what it produces, what it returns, and how to call it safely. The timeout warning is front-loaded before the auth note, so the agent sees the critical constraint before deciding.

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?

No output schema exists, but the description states 'Returns the full HTML', closing that gap. For a non-destructive, open-world generation tool, the agent has everything needed: input nature, output form, runtime, timeout risk, and auth behavior.

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 brief, style, and deliver_email are already documented well. The description only restates that input is a 'plain-language brief' and doesn't add syntax, defaults, or constraints beyond what the schema provides. Baseline 3 is appropriate.

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 artifact ('Generate a complete, responsive, single-page website (HTML)') plus the content it produces (real copy, inline-SVG, sections, contact form). This cleanly separates it from generate_form and generate_master_prompt without requiring the agent to open another 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?

Explicitly warns that the synchronous call will time out and names the preferred alternative ('prefer the async pair start_website + get_website instead'), with the reason (~1–3 minutes) attached. The when-to-use-vs-when-to-avoid guidance is stated directly.

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