pcb_create_arc

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

Annotations already declare this is a non-read-only, non-idempotent, non-destructive write. The description adds the coordinate-space convention (canvas mils, +X right, +Y up), which is real value, but discloses nothing about failure modes, whether a save is required afterward, or how the new primitive is returned. Adds some context beyond annotations, not rich behavioral detail.

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?

Three sentences, front-loaded with the action, followed by units and a pointer to helper tools. No filler, though the helper-tool sentence could be tightened. Appropriate length for a 10-parameter primitive-creation tool.

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 mutation tool with 10 parameters, no output schema, and full schema coverage, the description covers the critical ambiguity (units and coordinate frame) that the schema omits. It does not address the optional lineWidth or multi-instance behavior, but the schema and sibling guidance largely cover those.

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%, so the baseline is 3, but the schema's own parameter descriptions are thin ('Start X coordinate', 'Track width') and omit units entirely. The description compensates by specifying that coordinates and lengths are in mil and defining the axis orientation, which the schema does not.

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+resource: 'Create an arc track segment on the PCB.' An agent immediately knows this produces an arc primitive rather than a straight track. It does not explicitly distinguish itself from close siblings like pcb_create_track or pcb_create_polyline_track, but the arc/segment distinction is clear from the wording.

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 names two helper tools (pcb_canvas_origin, pcb_convert_coordinates) for coordinate handling, which is useful routing guidance. However, it never states when to choose this tool over the other track-creation siblings (pcb_create_track, pcb_create_polyline_track), so usage vs alternatives is only implied.

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