set_appearance

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

With no annotations, the description carries the full behavioral burden and does well: it discloses partial-update semantics ('What is left out stays as it was'), the assembly-vs-part colour ownership rule, and the reset behaviour of transparency 0. It does not mention persistence (whether a save is needed) or error behaviour, but the core mutation semantics are unusually explicit.

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 purpose is front-loaded in the first clause, followed by compact per-parameter clarification. Sentences are dense and mostly earn their place; the nested parenthetical on transparency is slightly heavy but still informative rather than filler.

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 3-parameter, no-annotation, no-output-schema mutation tool, the description covers purpose, all parameter formats, and key mutation semantics. It stops short of persistence/undo and permission context, but an agent has enough to invoke it 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 0%, so the description must compensate and largely does: rgb is documented as [r, g, b] with 0..255 range, transparency as a 0..1 scale with direction explained, and component as a naming convention with example paths. Formats and constraints for all three parameters are supplied beyond the bare 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 states a specific verb and resource: setting the colour and/or transparency of the current part or one assembly component. It clearly frames the tool as a visual-appearance operation, distinguishing it implicitly from geometry-modifying siblings like set_material or add_fillet, though it never names set_material to disambiguate appearance from material.

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?

Usage context is implied: the tool applies to 'the current part, or of one component in an assembly', and the component-name syntax hints at the assembly case. However, there is no explicit when-to-use vs when-not guidance and no named alternative (e.g. set_material for physical properties), leaving the agent to infer scope.

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