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

With no annotations, the description carries the full burden. It discloses the create operation, the immediate return value (tracking snippet), and the lifecycle state (pending until verified). This is meaningful behavioral context beyond the schema, though it omits idempotency and auth details.

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 concise sentences with no wasted words. The action is front-loaded, and the key consequences—return value and pending state—are stated clearly and efficiently.

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 simple one-parameter tool with no output schema, the description covers what it does, what the caller receives, and the resulting state. The only minor gap is not explicitly naming verify_site as the next step, but the pending state implies it. The definition is fully sufficient for correct invocation.

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?

The schema already provides 100% coverage for the single parameter, including a type and example ('The bare domain, e.g. example.com'). The description adds no extra semantic detail about the domain parameter, so the baseline of 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?

The description clearly states the specific operation ('Add a website to the account') and adds distinguishing details: it returns a tracking snippet and the site stays pending until verified. This differentiates it from sibling tools like verify_site and list_sites.

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?

The description implies the use case: register a new website to obtain a tracking snippet, and the 'pending until verified' note signals that verification is a separate step. It does not explicitly name the verify_site sibling or state when not to use this tool, so it falls just short of full guidance.

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