# Token Bid-Ask Spread — Adjacent Period Changes

> Token Bid-Ask Spread — Adjacent Period Changes is a paid API for AI agents from market.datapackvibe.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-16).

Computes period-over-period changes in bid-ask spread for a supplied sequence of token quote observations

## Facts

- Endpoint: POST https://market.datapackvibe.com/x402/assistant-bx-token-quote-spread-period-changes?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/token-bid-ask-spread-adjacent-period-changes-36080caf
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DKHt5JhR7BxFebuH6qcVB

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 token-bid-ask-spread-adjacent-period-changes-36080caf -d '<json body>'
```

Example prompt: Can you calculate the adjacent period changes in bid-ask spread for these token quotes: bid 0.98 ask 1.02, bid 1.078 ask 1.122, bid 0.98 ask 1.02, bid 1.078 ask 1.122?

## When to prefer this

Choose this endpoint when you have a time-ordered sequence of token bid and ask price observations and need a deterministic, period-by-period spread change report without running a live market scan. It is ideal for post-hoc analysis, backtesting pipelines, market-making calibration, or spread monitoring workflows where you supply your own quote data. Prefer alternatives if you need live market data feeds, trade recommendations, or safety signals.

## Known failure modes

- Fewer than 2 rows supplied — minimum of 2 bid/ask pairs required
- Ask or bid price is zero or negative — both must be strictly positive (exclusiveMinimum: 0)
- Ask or bid price exceeds maximum allowed value (10^16)
- Malformed row objects missing required 'ask' or 'bid' fields
- More than 200 rows supplied — exceeds maxItems limit
- Payment failure or insufficient USDC balance for x402 protocol

## How this service works

Token bid-ask spread — Adjacent period changes: Adjacent period changes for Token bid-ask spread. Supplied token observations only. Deterministic calculation or caller-threshold verdict, not a live scan, safety proof or trade recommendation. Specialised preset in a shared 50-profile, 20-operation engine. 0.01 USDC includes one bounded adjacent period changes report.

## Output

Returns a structured report of bid-ask spread changes between each pair of adjacent observation periods, computed deterministically from the supplied bid/ask price rows. The output includes spread deltas (difference in spread from one period to the next) for each consecutive pair of observations, up to 200 rows. This is a deterministic calculation — not a live market scan, safety proof, or trade recommendation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "rows": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "ask",
     "bid"
    ],
    "properties": {
     "ask": {
      "type": "number",
      "default": 1.02,
      "maximum": 10000000000000000,
      "minimum": 0,
      "exclusiveMinimum": 0
     },
     "bid": {
      "type": "number",
      "default": 0.98,
      "maximum": 10000000000000000,
      "minimum": 0,
      "exclusiveMinimum": 0
     }
    },
    "additionalProperties": false
   },
   "default": [
    {
     "ask": 1.02,
     "bid": 0.98
    },
    {
     "ask": 1.122,
     "bid": 1.078
    },
    {
     "ask": 1.02,
     "bid": 0.98
    },
    {
     "ask": 1.122,
     "bid": 1.078
    }
   ],
   "maxItems": 200,
   "minItems": 2
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/token-bid-ask-spread-adjacent-period-changes-36080caf/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from market.datapackvibe.com](https://www.zero.xyz/host/market.datapackvibe.com/llms.txt)