Persistence

--trade writes state under ~/.chartgen/ (Windows: %USERPROFILE%\.chartgen\). The directory is created on startup if missing. Override by setting $HOME before launch.

File	Written by	Format
alerts.json	set_alert, cancel_alert, fired alerts	JSON array, atomic replace
trades.log	Order lifecycle + alert triggers	Append-only text
subscriptions.json	subscribe_notifications, unsubscribe_notifications	JSON map keyed by token

alerts.json

Array of alerts awaiting evaluation. Each entry:

[
  {
    "id": "8f3a…",
    "symbol": "BTCUSDT",
    "condition": { "PriceAbove": 50000 },
    "created_at": "2026-04-19T12:00:00Z"
  },
  {
    "id": "b21c…",
    "symbol": "ETHUSDT",
    "condition": {
      "IndicatorSignal": { "indicator": "cipher_b", "signal": "gold_buy" }
    },
    "created_at": "2026-04-19T12:05:00Z"
  }
]

condition is a tagged enum with three variants:

• { "PriceAbove": <f64> }
• { "PriceBelow": <f64> }
• { "IndicatorSignal": { "indicator": "<name>", "signal": "<label>" } }

Writes use a .tmp + rename sequence so readers never see a partial file. The engine only rewrites alerts.json when the set changes (add, remove, or fire) — idle bars cost zero writes.

On-disk vs wire format

The condition keys above (PriceAbove, PriceBelow, IndicatorSignal) are PascalCase because the AlertCondition enum in src/trading/alert.rs uses serde’s default externally-tagged encoding. The MCP set_alert tool accepts snake_case (price_above, etc.) and translates it into the enum at the request boundary in src/mcp.rs. If you are editing alerts.json directly, use PascalCase; if you are calling set_alert over MCP, use snake_case — see the trading guide.

See the trading guide for the valid signal labels.

trades.log

Append-only audit trail. One line per event, UTC timestamps:

2026-04-19T12:34:56Z SUBMITTED buy BTCUSDT 0.01 market id=abc123
2026-04-19T12:34:57Z FILLED   buy BTCUSDT 0.01 @ 67432.5 id=abc123
2026-04-19T13:00:00Z CANCELLED id=def456
2026-04-19T13:15:22Z ALERT_TRIGGERED id=ghi789 cipher_b/gold_buy BTCUSDT 1h

Event types:

Prefix	Emitted by	Fields
SUBMITTED	place_order	side, symbol, quantity, type, id=<order_id>
FILLED	Exchange fill	side, symbol, quantity, @ <price>, id=<order_id>
CANCELLED	cancel_order	id=<order_id>
ALERT_TRIGGERED	Alert engine	id=<alert_id>, condition summary, symbol, interval

There is no rotation — rotate or truncate externally if it grows too large.

subscriptions.json

Persisted SSE push-notification filters, keyed by access token. Only symbols and alert_types are stored; SSE senders and offline queues are in-memory and rebuilt on reconnect.

{
  "<token>": {
    "symbols": ["BTCUSDT", "ETHUSDT"],
    "alert_types": ["price_above", "indicator_signal"]
  }
}

Both fields may be null, meaning “match any”. Restarting the server preserves filters so clients keep their filters across chartgen restarts, but queued alerts are lost.