# Tracking the Delta: How an AI Agent Watches Tokenized Stocks Drift From Their Underlyings

> Published: 2026-09-23 | Author: AgentBadge Team | Canonical: https://agentbadge.xyz/blog/bstock-delta-tracker-case

Picture this: Apple trades at $336.45 on Nasdaq. Tokenized Apple
(AAPLB on Binance) trades at $336.44 at the same moment. A penny apart —
noise. But on a Saturday night, with Nasdaq asleep, AAPLB can drift to
−2%. That is not noise anymore. That is a signal.

**The delta** — the gap between a tokenized stock’s
price and its underlying — is where the opportunities live. Humans
cannot watch 20+ tokens around the clock. A machine can. So we built a
tracker that computes the delta in real time and handed it to AI
agents.

![Two price lines - AAPLB token vs AAPL underlying - with the -2% delta band highlighted](/images/blog/bstock-delta-tracker-case-hero.png)

![Diagram: how the delta tracker works](/images/blog/bstock-delta-tracker-case-d1.png)
Diagram: how the delta tracker
works

*Binance streams token prices around the clock; Finnhub/Alpaca
supply the equity prices. DeltaEngine computes the delta, the market
phase (O/C/P) and the stale flag (15s without updates). The MCP server
exposes it to the agent through five tools, and Telegram receives an
alert the moment a delta crosses the 0.5% threshold.*

## What the tracker computes

For every bStock the tracker keeps two prices:

- **bStockPrice** — the token’s price on Binance, where
tokenized stocks trade 24/7;

- **underlyingPrice** — the real stock’s price from
market data providers (Finnhub, with an Alpaca fallback).

Delta in percent:
(tokenPrice − stockPrice) / stockPrice × 100. Alongside it,
three flags a trader actually needs:

- **phase** — is the stock market open (O),
closed (C), or in pre-market (P);

- **stale** — the price feed went quiet for more than 15
seconds, so treat the number with care;

- **inAlert** — the delta crossed the **0.5%
threshold** (configurable).

A live response looks like this:

[](#cb1-1){"symbol":"AAPLB","underlying":"AAPL","multiplier":1.0006,
[](#cb1-2) "bStockPrice":336.44,"underlyingPrice":336.45,
[](#cb1-3) "deltaPct":-0.064,"phase":"O","stale":false,"inAlert":false}
![get_delta JSON response with deltaPct and inAlert highlighted](/images/blog/bstock-delta-tracker-case-2.png)

## How an agent uses it

An AI agent is a program — Claude, a GPT-based bot, your own script —
that calls services on its own. Agents talk to services over
**MCP**, an open protocol where a service lists its tools
and the agent calls them like functions.

The tracker is an MCP server with these tools:

- get_delta — delta for one symbol;

- list_deltas — all symbols at once;

- get_quote — current quote;

- get_events — event history (threshold crossings, stale
feeds);

- get_digest — the day’s summary.

[](#cb2-1)curl -X POST https://agentbadge.xyz/mcp/bstock/tools/get_delta 
[](#cb2-2)  -H "Authorization: Bearer $TOKEN" 
[](#cb2-3)  -d '{"symbol": "AAPLB"}'
There is also Telegram: subscribe_telegram registers the
agent’s operator, and the tracker pushes a message whenever a delta
crosses 0.5%. No polling needed — the signal finds you.

![AI agent connected to the MCP tracker (Binance + Finnhub feeds, five tools) with a Telegram alert](/images/blog/bstock-delta-tracker-case-3.png)

## Freemium: a
snapshot for free, the stream for a fee

The first request each minute is free. After that the server answers
with **HTTP 402 Payment Required** — not an error, an
invoice: “want real-time? pay”. The x402 standard lets the agent pay
automatically: 5 USDC on the Arc network buys 30 days of access. No
signup, no card, one on-chain transaction — gas paid in USDC too, an Arc
specialty. The server verifies the transaction on-chain and opens the
door. The same payment cannot be replayed — replay protection is built
in.

![402 paywall flow: request rejected, USDC payment to the Arc vault, 30-day access badge](/images/blog/bstock-delta-tracker-case-4.png)

## Why a trader should care

A −0.06% delta is noise. A −2% delta on a closed exchange means “the
token was sold off and the equity has not woken up yet”. Whoever sees it
first captures the convergence. A person cannot monitor every token
every second — an agent can, and it pays for its own data feed without a
human in the loop.

*Next: inside the 402 paywall — how freemium works when the
customer is a machine.*

**Links**

- Agent guide (endpoints, limits, examples): [agentbadge.xyz/bstock-guide](https://agentbadge.xyz/bstock-guide)

- All articles in the series: [agentbadge.xyz/blog](https://agentbadge.xyz/blog)

- MCP endpoint:
https://agentbadge.xyz/mcp/bstock/tools/get_delta

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## For AI Agents

- Companion guide: https://agentbadge.xyz/agent-guide/articles/bstock-delta-tracker-case
- Knowledge Index: https://agentbadge.xyz/agent-guide/
- LLM entry point: https://agentbadge.xyz/llms.txt
- Engineering services: https://agentbadge.xyz/agent-guide/team/services