pcb_scale

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

With no annotations, the description carries the full burden and does well: it gives the exact transform math, states that sizes scale by the ratio, enumerates which primitive types are handled and which are silently skipped, and notes an error return. It does not say whether the operation is undoable or what happens when nothing is selected or ratio <= 0 beyond 'an error'.

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?

Front-loaded with the action and formula, then scope, then args and returns — a sensible order. The Args/Returns block repeats a little of what the structured output schema already covers, but no sentence is wasteful.

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 mutating, selection-dependent geometry tool with two parameters, the description covers the transform, scope, exclusions, parameters and error case. Remaining gaps are minor: no statement of selection prerequisite as an explicit requirement, and no undo/persistence note.

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 0%, so the description must compensate and it does: ratio is constrained to > 0 with concrete interpretation examples (0.95 shrinks 5%, 1.05 grows 5%), and anchor is enumerated with its three allowed values and the default. This is meaning the bare schema does not provide.

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?

States a specific verb (Scale) plus the exact resource (selected free primitives) and scope (about an anchor), and immediately delimits what is NOT affected: components, dimensions, polygons, footprints. An agent can distinguish this from placement/move tools in the sibling list without opening the schema.

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 the precondition (a selection of free primitives must exist) and explicitly carves out the excluded cases, so the agent knows this is not a footprint/resize tool. It falls short of naming an alternative tool for scaling footprint content, but no obvious sibling does that.

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