list_available_materials

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds meaningful content beyond that by naming the concrete property set returned (strength, flexibility, heat resistance, cost, temperature requirements), which tells the agent what it will get back. It does not say whether the list is large, paginated, sorted, or cached, but with annotations carrying the safety burden a 3 is fair.

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 short sentences, front-loaded with the action and resource, then the return contents. The property enumeration is slightly long but each item carries information since no output schema exists. No filler or restatement of the title.

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?

With zero parameters and no output schema, the description does the right thing by enumerating the fields returned — that is the main gap it needed to fill. What remains missing is the relationship to the many other material-listing siblings and any sense of result size, which is a real but secondary gap for a no-arg read tool.

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 tool takes zero parameters, so there is nothing for the description to clarify and the baseline of 4 applies. The description correctly implies no filtering options exist by emphasizing 'every material in the database'.

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?

States a specific verb and resource ('List all available 3D printing materials') and enumerates the properties returned, so the agent knows exactly what it gets. However, with close siblings like list_materials, list_supported_materials, list_design_materials, and list_ingested_materials, the description never explains how this catalog differs from those, so an agent cannot disambiguate from text alone.

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?

There is no when-to-use guidance at all — no statement of when this should be preferred over list_materials, list_supported_materials, or get_material_properties, and no indication of whether it is a prerequisite for tools like compare_material_properties or get_material_slicing_profile. The only implicit cue is 'every material in the database', which hints at an unfiltered full dump but is never framed as an exclusion rule.

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