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# bStock Delta Tracker — Agent Guide
Welcome, AI agent. This guide explains how to read tokenized-stock delta
data from the bStock tracker: Binance bStock prices vs underlying equity
prices (Finnhub/Alpaca), computed as a delta percentage per symbol.
## Overview
The tracker exposes a dedicated MCP namespace:
- **Endpoint:** `https://agentbadge.xyz/mcp/bstock`
- **Auth:** `Authorization: Bearer <token>` (agent tokens are issued
out-of-band; without one you get `401`)
- **Tools (read-only):** `get_delta`, `list_deltas`, `get_quote`,
`get_events`, `get_digest`
---
## Free tier
Every authenticated agent gets **1 req/min** for free — enough for
periodic delta checks and digests.
```bash
curl -X POST https://agentbadge.xyz/mcp/bstock/tools/get_delta \
-H "Authorization: Bearer $MCP_AGENT_TOKEN" \
-H "Content-Type: application/json" \
-d '{"symbol": "AAPLB"}'
```
JSON-RPC style works too:
```bash
curl -X POST https://agentbadge.xyz/mcp/bstock \
-H "Authorization: Bearer $MCP_AGENT_TOKEN" \
-H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0","id":1,"method":"tools/call",
"params":{"name":"list_deltas","arguments":{}}}'
```
---
## When to pay
If you need more than **1 req/min** — or real-time streaming — the free
bucket returns **HTTP 402** with a `PAYMENT-REQUIRED` header containing
base64-encoded x402 payment requirements.
Pay **$5 USDC** (Base Sepolia, EIP-3009) to mint a **ServicePass** for
`bstock-delta-realtime`, valid **30 days**:
1. Receive `402` + `PAYMENT-REQUIRED` header
2. Sign the payment (EIP-3009) and retry with a `PAYMENT-SIGNATURE` header
3. Server verifies + settles via the x402 facilitator, mints your pass
4. Include `X-Wallet: <your-wallet>` on subsequent calls — the pass is
checked on-chain and you get real-time access
Renewal: repeat the buy — the pass extends (`ServicePassExtended`).
---
## Rate limits
| Tier | Limit | Over-limit response |
|---|---|---|
| Free | 1 req/min per token | 402 + PAYMENT-REQUIRED |
| Paid | 60 req/min per token | 429 |
| SSE | max 20 concurrent connections | 503 |
---
## Tools
- `get_delta {symbol}` — delta% for one bStock symbol (e.g. `AAPLB`)
- `list_deltas {}` — all tracked symbols, sorted by |delta| desc
- `get_quote {symbol}` — latest bStock + underlying quote pair
- `get_events {limit?}` — recent delta alert events
- `get_digest {}` — rolling-window digest for periodic checks