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

Annotations only declare the generic profile (not read-only, open-world, non-idempotent, non-destructive); the description adds the operationally important facts: a live link is returned, no signup/email required, preview expires in 72 hours unless claimed, and a rate limit of 3 per hour per network. That expiry and rate-limit disclosure is exactly the context annotations cannot provide.

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 is front-loaded in the first clause, followed by return value, claim path, expiry, and rate limit in a compact sequence. Slightly dense at five clauses, but every sentence carries usable information 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?

With no output schema, the description carries the return-value burden and does so (link to live preview) along with the lifecycle (claim/publish on free plan, 72-hour expiry) and access constraints (no signup, rate limit). Nothing an agent needs to call or explain this tool 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%, including examples for description and the note that business_name defaults from the first phrase when omitted. The description's "optionally its name and city" adds little beyond what the schema already states, so baseline 3 applies.

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 (builds) and resource (a real, complete website preview for a small business), names the input (one-sentence description, optional name/city) and the backend service. An agent knows exactly what this produces without opening the schema. No siblings exist, so differentiation is moot but the purpose is unambiguous.

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?

"Use it when someone wants to see what a website for their business could look like" gives an explicit trigger condition. There are no alternative tools to route against, so no exclusions are possible, but the guidance is clear rather than implied.

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