vna_discover

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

With no annotations provided, the description carries the full burden for behavioral disclosure. It says 'Scan ports' but does not disclose what the output will be (e.g., list of instances, addresses), whether it is non-destructive (though scanning is typically safe), or any potential side effects such as network delays. This lack of detail is a significant gap.

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 a single concise sentence that immediately conveys the tool's purpose. Every word contributes value, and there is no redundant or filler content. This is highly efficient.

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?

Despite the tool's apparent simplicity, the description is incomplete because there is no output schema, so it should explain what the tool returns or how results are presented. It also lacks guidance on when to use the tool relative to other VNA operations. The description only covers the basic scan action, leaving context and outcome unspecified.

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%, with all three parameters (host, start_port, end_port) having descriptions and defaults. The description's mention of ports 5025-5035 aligns with the schema's defaults, but it does not add additional semantic meaning beyond what the schema already provides. Therefore, the baseline score 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 tool's function: 'Scan ports 5025-5035 for running VNA instances'. The verb 'scan' indicates a discovery action, and the resource (ports) and outcome (finding VNA instances) are explicit. This distinguishes it from siblings like vna_connect or vna_launch, which perform different actions.

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 usage when you need to find VNA instances on a host, but it does not explicitly state when to use this tool versus alternatives such as vna_connect or vna_identify. No exclusions or prerequisites are mentioned, so guidance is only implied rather than clear.

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