Add schematic polygon

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

Annotations only declare readOnlyHint=false and idempotentHint=false. The description adds real value beyond them: that the output is purely cosmetic with no electrical meaning, which tells the agent this write cannot affect the netlist. It does not mention the confirmWrite gate or any permission/idempotency nuance beyond what annotations already imply.

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?

One front-loaded sentence plus a short clause; every word earns its place, and the shape/scope constraint comes first.

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 primitive-drawing tool with annotations and an output schema, the description covers purpose, constraint, and cosmetic scope. It leaves the write-confirmation and styling parameters to the schema, which is acceptable but slightly thin given the low schema coverage.

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 only 33% across 6 parameters. The description compensates partially by stating '3+ vertices', reinforcing the points/minItems constraint, but says nothing about color, lineType, lineWidth, or fillColor. The confirmWrite semantics live only in the schema.

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?

Specific verb+resource+scope: 'Draw a closed polygon on the schematic sheet from 3+ vertices'. It is clearly distinguishable from the sibling primitives (add_rectangle, add_circle) because it names the shape and its drawing constraint.

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?

Gives concrete usage contexts ('custom decorative shapes, callout arrows, or block diagram elements') and a critical exclusion ('Cosmetic only, no electrical meaning'), which steers the agent away from using this for electrical intent. It does not, however, name the alternative primitive tools to use for other shapes.

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