Add Via

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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the base safety profile is known. The description adds no extra behavioral context, such as whether the via is automatically connected to the provided net, how layer selection works, or what side effects occur (e.g., DRC implications). It does not contradict annotations but also does not build on them.

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 extremely concise ('Add a via to the PCB' — six words) and front-loaded. Every word is necessary; there is no redundancy or filler. It is appropriately sized for the simple operation it describes.

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 has multiple parameters, nested objects, an output schema, and many sibling tools, the description is too sparse. It omits critical behavioral context such as coordinate interpretation, net existence requirements, and how this differs from adding arrays of vias (add_gnd_stitching_vias). For a board-modifying tool, more context would help the agent invoke it correctly.

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 input schema provides descriptions for all three parameters (net, viaType, position) with 100% coverage. The description 'Add a via to the PCB' does not add any parameter-level meaning, so a baseline score of 3 is appropriate where the schema does the heavy lifting.

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 'Add a via to the PCB' uses a specific verb ('Add') and resource ('via') with a clear target (PCB). It distinguishes from sibling tools like add_mounting_hole and add_board_outline by naming a unique PCB element, making the purpose unambiguous.

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 gives no guidance on when to use this tool versus alternatives such as add_gnd_stitching_vias (which also adds vias) or route_trace. It does not mention prerequisites (e.g., an open board) or provide any when-not-to-use instructions.

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