# Carbon & Cashmere Beta-to-BTC Signal API

> Carbon & Cashmere Beta-to-BTC Signal API 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 beta coefficient of BTC relative to itself (or a given coin) against BTC, including regime classification, R-squared, alpha, and 30-day rolling statistics.

## Facts

- Endpoint: GET https://api.carbon-cashmere.de/v1/beta-to-btc/BTC
- 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-f75977e7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pO-Tr5m8R3v0IgxN1R6E7

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-f75977e7
```

Example prompt: What's Bitcoin's current beta regime and stability — is it acting as an amplifier or dampener relative to the market, and what does the 30-day rolling beta look like?

## When to prefer this

Use this endpoint when you need quantitative beta and regime signals for BTC specifically — especially when you want to know how Bitcoin is behaving relative to the broader market (amplifier vs dampener), need R-squared and alpha metrics, or want rolling 30-day beta statistics. Prefer this over generic price APIs when the user wants statistical market characterization rather than just price data.

## Known failure modes

- Invalid coin ticker returns error or empty response
- Coin not tracked by Carbon & Cashmere returns 404 or null data
- Payment not included or insufficient (x402 payment required at $0.01 USDC per call)
- API in beta may have intermittent availability
- Lookback window insufficient data for some newer coins

## How this service works

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

## Output

Returns a JSON object with BTC's beta coefficient, regime label (e.g. 'amplifier'), R-squared fit, daily alpha percentage, stability classification, and 30-day rolling stats (mean, std, current beta) over a 90-day lookback window.

## 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-f75977e7/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)