Material List

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

Annotations already declare readOnlyHint=true, and the description adds meaningful behavioral detail: it returns a count, category, materials array, and sorted-by-name ordering. It also enumerates the accepted categories, giving the agent concrete expectations beyond the schema.

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?

One dense, well-structured sentence that front-loads the purpose, then states the optional filter, return shape, and sort order. Every element earns its place with no repetition or 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 single-optional-parameter list tool with no output schema, the description is complete: it documents allowed parameter values, the response structure, and ordering. An agent has everything needed to call 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?

The schema provides only a string/null category with no descriptions or enums. The description compensates fully by listing the allowed category values ('aluminum' | 'steel' | 'titanium' | 'magnesium' | 'polymer' | 'glass') and clarifying that filtering is optional. This is essential information for correct invocation.

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 uses a specific verb and resource ('List available materials') and clearly distinguishes this from siblings like material_get and material_select. The optional category filter and return shape further clarify exactly what the tool does.

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 gives clear context: call this to list available materials, optionally constrained to one category. It does not explicitly name when to prefer material_get or material_select instead, but the list-oriented wording makes the appropriate use case reasonably obvious.

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