Keel

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes key behavioral traits: the safety restriction to RFC 1918 subnets, the specific ports probed (TCP 22, 80, 443), and the scanning methodology. It doesn't mention rate limits, timeout behavior, or output format, but provides substantial operational context.

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?

The description is perfectly concise with three focused sentences that each add value: purpose statement, safety constraint, and technical details. No wasted words, and the most critical information (what the tool does) comes first.

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 network scanning tool with no annotations and no output schema, the description provides good coverage of purpose, constraints, and methodology. It could be more complete by mentioning output format or error conditions, but given the tool's relative simplicity, it's substantially complete.

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?

With 0% schema description coverage for the single 'subnet' parameter, the description compensates by explaining the parameter's constraints: it must be an RFC 1918 private subnet. This adds crucial semantic meaning beyond the bare schema, though it doesn't specify the exact format (CIDR notation, etc.).

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 action ('discover live hosts') and resource ('on a local subnet') with method details ('by probing common ports'). It distinguishes from sibling tools like 'port_scan' by specifying subnet scanning rather than individual host port scanning.

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 provides clear context about when to use this tool ('discover live hosts on a local subnet') and includes a safety constraint ('Only allows RFC 1918 private subnets'). However, it doesn't explicitly mention when NOT to use it or name specific alternatives among the sibling tools.

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