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

With no annotations, the description must carry the full behavioral burden. It usefully discloses the 10-port cap, TCP-only scope, a cost of 1 credit per call, and an authorization requirement. It omits the return shape, timeout/failure behavior, and whether it is a safe read-only probe.

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 short sentences, purpose front-loaded, with the constraint and cost appended. Every sentence adds distinct information with no padding.

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 2-parameter, no-output-schema tool, the description covers purpose, limits, cost, and legal constraints. The main gap is that the result format of the check is left to inference, which matters when no output schema exists.

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 0%, so the description must compensate. It maps loosely to both params ('public host' for host, 'TCP ports' for ports) but adds no format, default, or constraint detail beyond what the schema already encodes.

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+resource with scope: 'Check whether up to 10 TCP ports are open on a public host.' This is clear and distinguishes the operation from ping/traceroute, though it never names a sibling to route against.

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 only usage context is a legal constraint ('Only scan systems you own or are authorized to test'). There is no guidance on when to prefer this over ping, traceroute, dns_lookup, or tls_certificate, nor any exclusions or prerequisites beyond authorization.

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