cst_pcb_calculate_coupling

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

With no annotations, the description carries full behavioral burden. It clearly states it is a pure calculation with no geometry generation, which is helpful. However, it does not disclose whether it modifies project state, requires prior setup, or any side effects. The read-only nature is implied but not explicitly confirmed.

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: two sentences with no extraneous words. It front-loads the core purpose and adds a clarifying statement about no geometry generation. Every sentence adds value.

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 computes complex quantities but has no output schema, and the description does not specify the format, structure, or units of the return value. For an agent to use this tool correctly, it needs to know what the output looks like. Additionally, prerequisites (e.g., existing PCB stackup or trace definitions) are not mentioned. The description is incomplete for practical use.

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 description coverage is 100%, so the input schema already explains all 6 parameters. The description does not add additional parameter-specific meaning or usage tips. Baseline score of 3 is appropriate as the schema handles parameter documentation.

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 explicitly states the tool calculates electromagnetic coupling between parallel PCB traces, lists specific computed quantities (even/odd mode impedances, coupling coefficient, crosstalk), and clarifies it is a pure calculation with no geometry generation. This clearly distinguishes it from sibling tools that create or modify geometry.

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 implies it is used for analytical coupling calculations without creating geometry, but it does not explicitly state when to use this tool versus alternatives like cst_pcb_differential_pair or cst_array_mutual_coupling. No usage exclusions or alternative tool references are provided.

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