Microstrip Impedance (IPC-2141)

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

Annotations already declare readOnlyHint and idempotentHint, so the description adds value by providing the exact formula, valid range, and output structure. This gives agents deeper understanding of the computation, surpassing what annotations convey.

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 extremely concise: formula, validity conditions, parameter list, return format, and an example, all in a few lines. Every sentence adds value; no redundancy. It is front-loaded with the most critical information.

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 straightforward nature of a microstrip impedance calculator, the description covers all necessary aspects: formula, valid range, parameter details, output format, and a concrete example. The presence of annotations and output schema further reduces the burden on the description, making it highly 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?

Input schema covers all parameters with descriptions, but the description adds physical context: units (mm), typical values for trace_thickness_mm (1oz = 0.035 mm) and er (FR-4 ≈ 4.2-4.6), and the formula linkage. Since schema coverage is 100%, baseline is 3; the description meaningfully enhances parameter understanding, earning a 4.

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 it computes surface microstrip characteristic impedance using the IPC-2141 formula. It distinguishes itself from sibling calculators (e.g., pcb_trace_width) by specifying the specific calculation and providing the formula. The verb 'impedance' and resource 'microstrip' are 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?

The description includes validity constraints (0.1 < w/h < 2.0, εr < 15), which implicitly guide when to use the tool. However, it does not explicitly compare with siblings or state when not to use it, missing some guidance for an agent to choose among similar calculators.

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