# M2M Trust SPC Audit – Statistical Process Control Analysis

> M2M Trust SPC Audit – Statistical Process Control Analysis is a paid API for AI agents from energybilltoolkit.co.uk, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Runs a deterministic Lean Six Sigma SPC audit comparing a current value against control limits and recent historical data to flag process violations.

## Facts

- Endpoint: POST https://energybilltoolkit.co.uk/m2m-trust/api/tools/spc-audit
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/energybilltoolkit-co-uk-5606a719
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_aOG-CWZfCV4Plwq0Yl59-

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability energybilltoolkit-co-uk-5606a719 -d '<json body>'
```

Example prompt: Run an SPC audit on my latest boiler pressure reading of 4.7 bar — my recent history is [4.5, 4.6, 4.4, 4.7, 4.5, 4.6, 4.8] and my upper control limit is 5.0, lower control limit is 4.0. Tell me if it's in control and flag any rule violations.

## When to prefer this

Use this endpoint when you need a fast, deterministic, reproducible SPC audit for a single current value against its control limits and recent history — especially in M2M or automated quality monitoring pipelines where LLM-based analysis would be non-deterministic. Prefer over generic statistics endpoints when you specifically need Lean Six Sigma SPC rule checking (e.g. Western Electric rules, Nelson rules).

## Known failure modes

- Missing required current value returns 400 validation error
- Insufficient history data points may result in unreliable SPC signals
- Control limits not provided or malformed returns error
- Non-numeric values in history array cause parse failure
- Values outside plausible range may return warnings

## How this service works

M2M Trust deterministic analysis tool: Lean Six Sigma SPC audit for a current value against control limits and recent history.

## Output

Returns a deterministic SPC audit report indicating whether the current value is within control limits, which (if any) SPC rules are breached, process stability status, and signals derived from the recent measurement history.

## Example request

```json
{
 "buffer": [
  4.5,
  4.6,
  4.4,
  4.7,
  4.5,
  4.6,
  4.8
 ],
 "context": "boiler_pressure_bar",
 "lower_limit": 4,
 "upper_limit": 5,
 "current_value": 4.7
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "buffer": {
   "type": "array",
   "items": {
    "type": "number"
   },
   "description": "Recent historical values, oldest to newest."
  },
  "context": {
   "type": "string",
   "description": "Short domain context for interpretation."
  },
  "lower_limit": {
   "type": "number",
   "description": "Lower control/specification limit."
  },
  "upper_limit": {
   "type": "number",
   "description": "Upper control/specification limit."
  },
  "current_value": {
   "type": "number",
   "description": "Latest measured process value."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/energybilltoolkit-co-uk-5606a719/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from energybilltoolkit.co.uk](https://www.zero.xyz/host/energybilltoolkit.co.uk/llms.txt)