vibe-hardware-mcp

calculate_pcb_trace_impedance

Computes PCB microstrip/stripline impedance, differential Zdiff, propagation delay, and recommended trace width for a target impedance or DC current with IPC-2152 thermal checks.

Instructions

Local PCB transmission-line impedance & IPC-2152 trace current calculator. Computes single-ended microstrip/stripline Z0 (Ohms), edge-coupled differential Zdiff (Ohms), propagation delay (ps/mm), and recommended trace width for a target impedance or DC current (Amps).

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "calculate_pcb_trace_impedance"
  }
}

Input Schema

Name	Required	Description	Default
`er`	No	Relative permittivity Er of substrate (FR-4 = 4.4)
`mode`	No		microstrip
`current_amps`	No	Target DC current in Amps for IPC-2152 temp rise check
`trace_width_mm`	No	Trace width W in mm
`max_temp_rise_c`	No	Maximum allowed temperature rise in Celsius
`copper_weight_oz`	No	Copper weight in oz/ft^2 (1.0 oz = 0.035 mm)
`trace_spacing_mm`	No	Edge-to-edge spacing S in mm for differential pair
`dielectric_height_mm`	No	Dielectric height H to reference plane in mm

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 10, 2026

TDQS

A3.6/5.0

Behavior3/5

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

With no annotations, the description carries the full behavioral burden. It usefully signals a local, deterministic computation and names the governing standard (IPC-2152), but it does not state accuracy assumptions, whether results are estimates versus validated models, or how conflicting inputs (e.g., trace_width_mm alongside a target-impedance recommendation) are resolved.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two dense sentences with zero filler: the first establishes identity and standard, the second lists exactly what is computed with units. The most load-bearing information (what the tool returns) is front-loaded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, so the enumerated return values (Z0, Zdiff, delay, recommended width) do a good job of telling the agent what to expect from an eight-parameter tool. The main residual gap is that behavior around partially specified inputs and the meaning of a 'recommended' width versus a supplied one is left unstated.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 88%, so nearly every parameter is already documented in the schema, making 3 the baseline. The description adds only the units and physical meaning of the outputs (Ohms, ps/mm, Amps) rather than new semantics for the eight inputs, and it does not clarify how mode selection interacts with the differential-pair parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('PCB transmission-line impedance & IPC-2152 trace current calculator') and enumerates concrete outputs: single-ended microstrip/stripline Z0, edge-coupled differential Zdiff, propagation delay in ps/mm, and recommended trace width. It is unmistakable which tool this is within the PCB cluster, though it never explicitly contrasts itself with analysis siblings like analyze_kicad_pcb or audit_pcb_dfm_rules.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied: the word 'Local' and the enumerated outputs suggest a standalone analytical calculator rather than a board-inspection tool, which is a useful cue. However, there is no explicit statement of when to choose this over the sibling PCB analysis tools, and no mention of prerequisites such as needing a known stackup.

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

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