cst_pcb_calculate_coupling

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

With no annotations, the description carries the burden and does well: it explicitly states the tool is a pure calculation with no VBA or CST geometry side effects, which is the key behavioral fact for an agent. It also frames results as 'estimates', hinting at approximation. It stops short of stating assumptions or validity limits of the coupled-microstrip formulas.

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?

Three short sentences, front-loaded with the purpose and the computed outputs, then the no-side-effects caveat. No filler text.

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 pure-calculation tool with no output schema and no annotations, the description tells the agent what is computed and that nothing is written to CST, which is enough to call it correctly. Missing only the validity domain of the microstrip approximation and rough output magnitude/units.

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 clear units and meanings for all six required parameters, so the baseline is 3. The description adds only that the inputs feed coupled microstrip formulas; it introduces no additional semantics, ranges, or constraints beyond the schema.

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 ('Calculate electromagnetic coupling between parallel PCB traces') and enumerates the computed quantities (even/odd mode impedances, coupling coefficient, NEXT/FEXT). It does not name a sibling alternative such as cst_array_mutual_coupling or cst_matching_microstrip_impedance, but the 'no VBA or CST geometry is generated' clause does separate it from the geometry-creation PCB tools.

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 'Pure calculation. No VBA or CST geometry is generated.' note implies this is a quick analytic estimate rather than a solver run, which is useful context. However, it never says when to prefer this over a full simulation or a sibling like cst_array_mutual_coupling, and gives no prerequisites or exclusions.

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