list_supplies

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

Without annotations, the description fully discloses the side effect of writing a 'benign query' to serial ports, which is critical for an agent to understand. This goes beyond what a read-only annotation would provide, though it omits details about error cases or return format.

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 sentences, zero wasted words. The first sentence states the purpose, the second adds essential behavioral context. This is optimally concise.

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?

Given the tool's simplicity (no params, clear purpose) and presence of an output schema, the description is nearly complete. It hints at the output fields ('port + model max V/A'), which suffices for an agent to understand the tool's function.

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 tool has no parameters, so per guidelines the baseline is 4. The description adds no parameter information (none needed), and the purpose is clear without them.

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 action ('Probe USB-serial ports for supplies') and what information is returned ('port + model max V/A'). This distinguishes it from sibling tools which operate on individual supplies rather than discovering them.

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 a behavioral warning ('writes a benign query') and a usage recommendation ('prefer a pinned DEVPSU_PORT'), giving clear context for when to use the tool cautiously. However, it does not explicitly state when not to use it or mention alternatives.

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