pcb_place_arc

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

With no annotations, the description does carry behavioral detail: it names units in mils and degrees, gives defaults for start/end angle, width, and layer, and states that a geometry dictionary is returned. However, it does not disclose side effects, prerequisites such as requiring an open PCB document, or what happens if the layer is invalid.

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 definition is front-loaded: the first sentence states the action and target, the second clarifies the geometry, and the Args/Returns sections are compact and scannable. No sentence is wasted.

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 seven-parameter placement tool with no annotations and an existing output schema, the description covers the core geometry, units, defaults, and return summary. It could additionally state that an active PCB document and valid layer are required, but the essential calling information is present.

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 documents all seven parameters with meaning and units: x_center/y_center and radius in mils, angles in degrees, width in mils, and layer defaulting to TopLayer.

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 states a specific verb and resource: place an arc on the active PCB. It further clarifies that this creates a circular arc segment defined by center, radius, and angular range, which distinguishes it from generic drawing or placement tools.

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 by saying the arc is placed on the active PCB, but it does not explicitly compare this tool with alternatives such as pcb_place_tracks, pcb_place_region, or lib_add_footprint_arc. There are no when-not-to-use conditions.

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