# Carbon & Cashmere Beta-to-BTC Signal API – SOL

> Carbon & Cashmere Beta-to-BTC Signal API – SOL is a paid API for AI agents from api.carbon-cashmere.de, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Returns the 90-day rolling beta of SOL relative to BTC, including market regime classification, alpha, R-squared, and stability metrics.

## Facts

- Endpoint: GET https://api.carbon-cashmere.de/v1/beta-to-btc/SOL
- 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/carbon-cashmere-beta-to-btc-signal-api-sol-99038609
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_43u4OsSCYoffZRlRnJVPl

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 carbon-cashmere-beta-to-btc-signal-api-sol-99038609
```

Example prompt: What's SOL's current beta against Bitcoin — is it an amplifier or dampener right now, and how stable has it been over the past 30 days?

## When to prefer this

Use this endpoint when you need a quantitative, regression-based measure of how SOL moves relative to BTC — specifically when you want the market regime label (amplifier/dampener), R-squared confidence, and rolling stability stats in a single call rather than computing beta manually from raw price feeds.

## Known failure modes

- Unsupported coin symbol returns an error or empty result
- Network latency or API downtime returns a 5xx error
- Stale or missing market data may affect beta accuracy
- Invalid endpoint path format returns 404

## How this service works

Professional crypto market intelligence. Real-time prices, signals, and market scoring.

## Output

A JSON object with SOL's 90-day beta vs BTC, the current market regime label (e.g. 'amplifier'), daily alpha percentage, R-squared fit quality, a rolling 30-day window with mean/std/current beta, stability classification ('stable' or otherwise), and a disclaimer noting the data is for informational research only.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "beta": 1.12,
  "coin": "ETH",
  "_meta": {
   "disclaimer": "Informational research data only — not investment advice."
  },
  "regime": "amplifier",
  "r_squared": 0.78,
  "stability": "stable",
  "rolling_30d": {
   "std": 0.08,
   "mean": 1.11,
   "current_beta": 1.15
  },
  "lookback_days": 90,
  "alpha_daily_pct": -0.02
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/carbon-cashmere-beta-to-btc-signal-api-sol-99038609/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.carbon-cashmere.de](https://www.zero.xyz/host/api.carbon-cashmere.de/llms.txt)