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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower. The description still adds real behavioral context beyond them: the checks run in parallel, and the result is an overall score plus verdict rather than raw signals. It omits rate limits, latency expectations, and what happens on partial failures.

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 short sentences with no filler; the scope of the combined scan is front-loaded and the routing hint follows. Every clause carries information an agent can act on.

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 single-parameter read-only scan with no output schema, the description covers what is checked and what kind of result comes back (score and verdict), which is the important missing piece. It stops short of explaining how the score is composed or how partial failures are surfaced, but nothing critical to invocation is absent.

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?

Only one parameter, and the schema description already documents it at 100% coverage. The description adds nothing about URL format, protocol requirements, or accepted input shapes beyond what the schema states, so this sits at the documented baseline.

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 ('combined website check') and enumerates exactly which signals it aggregates: security headers, URL reputation, and passive subdomain discovery. This lets an agent distinguish it from the overlapping siblings security_headers, url_reputation, and subdomains without opening any 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?

Provides a clear routing rule: use this combined call for a full posture check, use 'the individual tools when you need a single signal.' The when-not condition is explicit, though the alternative tools are referenced generically rather than by name, so the agent must still map 'individual tools' to the siblings.

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