set_arc

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

Annotations have readOnlyHint=false and destructiveHint=false, consistent with mutation. The description adds behavioral context: parameters in radians, innerRadius range 0-1, omitted fields keep current value, and return format. No contradictions.

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?

Two well-structured sentences with front-loaded purpose. Each sentence adds essential information: first sentence states action and target, second elaborates on parameters and their effects. No wasted words.

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?

Given 4 parameters, full schema coverage, no output schema, and annotations, the description covers all necessary aspects: parameter semantics, constraints (ellipses only), default behavior (omitted fields unchanged), and return value. Complete for the tool's complexity.

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 parameters are documented structurally, but the description adds meaning: explains radians with concrete examples (2π full circle) and innerRadius effect on shape (solid disc vs ring). This clarifies usage beyond 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?

The description clearly states the tool transforms an ellipse into a pie slice or ring by setting arc data. It specifies the resource (ellipse) and distinguishes from siblings like set_fills or set_strokes by noting that only ellipses have arc data.

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 explains the parameter effects (full circle, half, solid disc, ring) and states that any subset of fields can be passed with at least one required. It implies when to use (for ellipses only) but does not explicitly mention alternatives or when not to use.

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