material.list

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds useful context beyond that: it explains the node-linked behavior and explicitly states 'The source file is never modified,' reinforcing the read-only guarantee. It also clarifies why node-link status matters. This is above the baseline of simply relying on 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 concise, with the core purpose in the first sentence and supplementary behavior in the second. It does not waste words, and the critical info is front-loaded. Minor structural improvement could be separating the 'never modified' statement into its own sentence, but it is already clear.

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?

The output schema is present, so return format is covered. However, the input parameter is completely unexplained, which is essential for correct invocation. The description also leaves ambiguity about whether it lists all materials or only those with Principled BSDF shaders. For a tool with one required parameter and no schema description, this is a significant completeness gap.

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?

The single parameter input_path has 0% schema description coverage, and the description does not mention it at all. An agent has no clue what input_path should be (likely a file path, but the format or meaning is undefined). Since the description is the only place to compensate for the missing schema detail, this is a critical 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 clearly states that the tool lists materials and specific Principled BSDF properties (Base Color, Roughness, Metallic, Alpha). It also reports node-link status for Base Color. The verb 'list' is precise, and the resource and fields are named, making the purpose unambiguous and distinguishable from siblings like apply_material or export.

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 implies it is a read-only inspection tool but does not explicitly state when to use it versus alternatives like scene.inspect or asset.apply_material. It provides context about the node-linked override but lacks clear 'use this when' or 'use this instead' guidance. The safer read-only nature is inferred but not stated as a selection criterion.

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