calc_impedance

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

With no annotations provided, the description must disclose behavioral traits. It does not mention defaults (though defaults exist in schema), accuracy, units, or return behavior. The user is left to infer that it performs a standard impedance calculation, but details on assumptions (e.g., typical FR4 parameters) are missing.

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 a single short sentence that immediately states the main purpose and supported modes. It is highly concise and front-loaded. However, some additional context could be included without sacrificing brevity, such as a note on output or default assumptions.

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 tool has no output schema, and the description does not explain what the function returns (impedance value, width, or both). Given the complexity of calculating impedance and reverse operation, the description should mention the computed result. This omission makes it incomplete for an agent to understand the full tool behavior.

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?

Schema coverage is 100% with each parameter described. The description adds no additional meaning beyond the schema. Baseline is set at 3, and no extra value is provided.

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 the tool's purpose: calculate PCB trace impedance or back-calculate line width based on target impedance. It specifies supported line types (microstrip, stripline, differential modes), which distinguishes it from sibling calc_trace_width that likely focuses on width calculation for current carrying. However, it does not explicitly compare with siblings, so it falls short of a 5.

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?

No guidelines on when to use this tool versus alternatives like calc_trace_width. No when-to-use or when-not-to-use context is provided. The description only states what the tool does, not the conditions under which it should be chosen.

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