physbound 0.1.1

Physical Layer Linter — validates RF and physics calculations against hard physical limits

PhysBound

Physical Layer Linter — An MCP server that validates RF and physics calculations against hard physical limits. Catches AI hallucinations in engineering workflows.

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What LLMs Get Wrong

LLMs routinely hallucinate physics. PhysBound catches it:

#	Category	LLM Hallucination	PhysBound Truth	Verdict
1	Shannon-Hartley	"20 MHz 802.11n at 15 dB SNR achieves 500 Mbps"	Shannon limit: 100.6 Mbps	CAUGHT
2	Shannon-Hartley	"100 MHz 5G channel at 20 dB SNR delivers 2 Gbps"	Shannon limit: 665.8 Mbps	CAUGHT
3	Antenna Aperture	"30 cm dish at 1 GHz provides 45 dBi gain"	Aperture limit: 7.4 dBi	CAUGHT
4	Thermal Noise	"Noise floor of -180 dBm/Hz at room temperature"	Actual: -174.0 dBm/Hz at 290K	CAUGHT
5	Link Budget	"Wi-Fi at 2.4 GHz reaches 10 km at -40 dBm"	Actual RX power: -94.1 dBm	CAUGHT
6	Link Budget	"1W to GEO with 0 dBi antennas at -80 dBm"	Actual RX power: -175.1 dBm	CAUGHT

Generated automatically by pytest tests/test_marketing.py -s

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Quick Start

Install

pip install physbound

MCP Client Configuration

Add PhysBound to any MCP-compatible client. For example, in Claude Desktop (claude_desktop_config.json), Cursor, or Windsurf:

{
  "mcpServers": {
    "physbound": {
      "command": "uv",
      "args": ["run", "--from", "physbound", "physbound"]
    }
  }
}

Your AI assistant now has access to physics-validated RF calculations.

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Tools

rf_link_budget

Computes a full RF link budget using the Friis transmission equation. Validates antenna gains against aperture limits.

Example: "What's the received power for a 2.4 GHz link at 100 m with 20 dBm TX, 10 dBi TX gain, 3 dBi RX gain?"

Returns: FSPL, received power, wavelength, and optional aperture limit checks. Rejects antenna gains that violate G_max = eta * (pi * D / lambda)^2.

shannon_hartley

Computes Shannon-Hartley channel capacity C = B * log2(1 + SNR) and validates throughput claims.

Example: "Can a 20 MHz channel with 15 dB SNR support 500 Mbps?"

Returns: Theoretical capacity, spectral efficiency, and whether the claim is physically possible. Flags violations with the exact percentage by which the claim exceeds the Shannon limit.

noise_floor

Computes thermal noise power N = k_B * T * B, cascades noise figures through multi-stage receivers using the Friis noise formula, and calculates receiver sensitivity.

Example: "What's the noise floor for a 1 MHz receiver at 290K with a two-stage LNA chain?"

Returns: Thermal noise in dBm and watts, cascaded noise figure, system noise temperature, and receiver sensitivity.

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Physics Guarantees

Every calculation is validated against hard physical limits:

• Speed of light: c = 299,792,458 m/s — no exceptions
• Thermal noise floor: N = -174 dBm/Hz at 290K — the IEEE standard reference
• Shannon limit: C = B * log2(1 + SNR) — no throughput claim exceeds this
• Aperture limit: G_max = eta * (pi * D / lambda)^2 — antenna gain is bounded by physics

Violations return structured PhysicalViolationError responses with LaTeX explanations, not silent failures.

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Development

# Clone and install
git clone https://github.com/JonesRobM/physbound.git
cd physbound
uv sync --all-extras

# Run tests
uv run pytest tests/ -v

# Print hallucination delta table
uv run pytest tests/test_marketing.py -s

# Start MCP server locally
uv run physbound

License

MIT License. See LICENSE.