Add schematic circle

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

Annotations declare readOnlyHint=false and idempotentHint=false, so the agent already knows this mutates state. The description usefully adds that the result carries no electrical meaning, but says nothing about the confirmWrite confirmation gate, persistence, or undo behavior, which matter for a write tool.

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 short clauses, front-loaded with the action and its classification. No filler, though the trailing fillColor note is the one piece that merely echoes structured data.

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?

An output schema exists, so return values need not be described, and annotations cover the safety profile. Still, for a 4-required-parameter write operation with 22% schema coverage, the definition leaves the geometry parameters and the write-confirmation requirement unexplained.

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 only 22% across 9 parameters. The description explains only fillColor 'none' — which the schema already documents verbatim — and says nothing about centerX/centerY coordinate space, radius units, lineWidth, lineStyle, or the required confirmWrite boolean.

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 and resource ('Draw a circle on the schematic sheet') and immediately classifies it as cosmetic, which separates it in kind from its electrical siblings like add_wire or create_net_flag. It does not explicitly name the add_rectangle/add_polygon alternatives, but the resource is 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 phrase 'decorative marker or custom symbol element' implies when to reach for this tool, and 'Cosmetic only, no electrical meaning' signals when not to. However, it never routes the agent to a sibling primitive tool or states any precondition, so usage is only implied.

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