set_principled_bsdf

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

With no annotations provided, the description must disclose behavioral traits, but it only states that it sets properties. It does not indicate whether the material or node must exist, whether it creates them if absent, what happens if a property is not applicable, or whether it overwrites or merges values. The side effects and error behavior remain opaque.

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 a single sentence and is syntactically concise, but it is under-specified for a tool with 16 parameters and no other context. It is not front-loaded with critical information—it merely restates the tool's core action without enriching it. The brevity does not compensate for the missing guidance.

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 the complexity (16 parameters, no annotations, no output schema details), the description is woefully incomplete. An agent cannot determine when to use it, what prerequisites exist, what each parameter does, or what the expected result or errors are. The description fails to provide enough context for safe and correct invocation.

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 0%, so the description must compensate by explaining parameter meaning, but it does not mention any of the 15 properties (e.g., ior, alpha, metallic). The parameter names are self-explanatory to those familiar with the Principled BSDF node, but the description adds no value beyond what the schema already provides, leaving a significant gap.

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 action ('set') on a specific resource ('Principled BSDF node properties on a material'), which clearly distinguishes it from generic material creation or assignment tools. However, it does not explicitly differentiate from overlapping siblings like set_shader_node_property or set_shader_node_value, so it misses some sibling differentiation.

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?

No guidance is provided on when to use this tool versus alternatives. The description does not mention prerequisites (e.g., an existing material with a Principled BSDF node) or scenarios where another tool like set_shader_node_property would be more appropriate. No exclusions or alternatives are named.

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