si_list_dielectric_materials

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

No annotations are present, so the description carries the full burden. It clearly states the output content (Er, loss tangent, frequency range) but does not mention that this is a read-only listing or any limitations (e.g., no filtering, no custom materials). For a simple list tool, this is adequate but lacks depth.

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: the first clearly states the tool's function with key output attributes, the second gives a practical usage tip. No wasted words, front-loaded, and easy to parse.

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 existence of an output schema, the description doesn't need to enumerate return fields. It covers the core purpose and provides a critical integration hint with a sibling tool. For a simple list operation, this is complete.

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 has zero parameters, so the input schema is trivial. Per the rubric, a zero-parameter tool receives a baseline of 4, and the description doesn't need to explain any parameter semantics.

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: 'List all built-in dielectric materials' with the exact attributes returned (Er, loss tangent, frequency range). This clearly distinguishes it from sibling SI tools that calculate or synthesize, and it names a specific sibling for downstream use.

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 explicit context: 'Use the returned material keys with si_synthesize_stackup_for_interfaces() to select the appropriate laminate for your design.' This tells the agent when and with what to pair this tool, though it doesn't provide explicit 'when not to use' or alternative comparisons.

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