list_materials

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is known. The description adds the behavioral fact that the full list is large (affecting response size/performance) and explains that scene_settings contains exact values needed for create_scene, which is valuable context beyond the 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?

Two sentences, zero filler. The primary purpose and the key relationship to create_scene are front-loaded, followed by a single actionable usage note. Every clause earns its place.

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 simple read-only list tool with one optional parameter and no output schema, the description covers purpose, parameter usage, and hints at the response structure (scene_settings fields). Nothing an agent needs to call it correctly is missing.

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?

With 0% schema description coverage, the description fully compensates by explaining that machine_type filters to one printer family and that the list is large without it. This gives the parameter clear semantic meaning that the schema alone (a bare string) lacks.

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 clear verb ('List') and resource ('printers with their materials and print settings'), and distinguishes itself from siblings like list_printer_types by focusing on materials and settings. It also ties the output to create_scene, making its unique purpose explicit.

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?

It explicitly advises passing machine_type to filter to one printer family because the full list is large, which is a clear usage condition. It doesn't name alternatives, but the link to create_scene implies when this tool is needed, and the filter guidance is actionable.

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