set_fills

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

Annotations already indicate a mutating operation (readOnlyHint=false, destructiveHint=false). The description adds value by disclosing the return format ({ ok, nodeId }) and the expected input structures, including the note about compatibility with get_node output. No contradiction with annotations.

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?

The description is compact—three sentences that front-load the purpose, then provide examples and return info without unnecessary words. Each sentence adds meaningful detail and the structure is easy to scan.

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 setter tool with rich schema and annotations, the description covers the main purpose, input formats, and return value. It does not discuss error cases or side effects, but given the simplicity of the operation, this is acceptable and leaves the agent sufficient context to invoke correctly.

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 schema already documents both parameters and their types. The description enriches this by providing concrete syntax examples, clarifying color value ranges (0–1), and explaining the gradientTransform shape, which goes beyond the schema's descriptions.

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 opens with 'Set a node's fills', a specific verb+resource that clearly identifies the tool's function. It further distinguishes itself from sibling tools (e.g., set_strokes, set_effects) by explicitly describing SOLID and gradient paint structures, making the purpose 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 description clearly implies when to use this tool (to set fills on a node) and provides format details. It does not explicitly name alternatives or exclusions, but the 'round-trips get_node output' phrase suggests a typical edit workflow, offering contextual guidance without being exhaustive.

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