name	midas-core
tagline_fr	Un moteur Brain/Hands open source pour agents IA en paper trading — la sécurité vit dans le broker, pas dans le prompt.
tagline_en	An open Brain/Hands engine for paper-trading AI agents — safety enforced by the broker, not the prompt.
facts_fr	Licence MIT, Python 3.12+, 15 codes de garde-fou du broker, desk de démo exécutable, pip install midas-core.
facts_en	MIT license, Python 3.12+, 15 broker safety-rail reason codes, a runnable demo desk, pip install midas-core.

midas-core

An open, multi-agent paper-trading fund-manager framework built on a Brain/Hands split: agents author decisions; a broker enforces the safety rails and executes them. This repo is the reusable core — the engine, the config-driven roster/allocator model, a runnable demo desk, and the deterministic Hands pipeline. Bring your own agents.

The whole thesis in one command. Two orders, same agent, same instant: the broker fills the 3-share clip and refuses the 10-share one against a $5,000 notional cap it enforces itself. Reproduce it with the quickstart below — nothing above is mocked.

Paper-trading by default. This is a framework, not a service: it never executes against your broker keys, never pools funds, never gives per-user advice. See DISCLAIMER.md.

Why this exists

• Safety lives in the broker, not the prompt. The persona is aspirational; the broker is enforcing. Every order is checked at fill time against a fixed set of 15 rejection/cancel reason codes — MAX_ORDER_NOTIONAL, MAX_ORDERS_PER_DAY, TICKER_NOT_IN_UNIVERSE, INSUFFICIENT_CASH, DAILY_DRAWDOWN_HALT, … — so a coaxed or confused agent still can't slip an oversized or out-of-universe trade through.
• Reproducible by construction. Dependencies are a fully-pinned lockfile; prices and index universes are committed to git; a trading session makes no outbound HTTP calls. Every fill is stamped with executed_sha, the git HEAD it executed against — git checkout <sha> re-derives the exact order and price store the broker saw.
• Proven on a live desk. A 10-agent desk has run this engine every weekday since 2026-04-17, narrated publicly at midas.revah.paris. This repo is a one-way code mirror of that desk's engine — the same code, without the private data ledger.
• Conditional orders, not just market orders. Agents can defer a trade until a price level is crossed. Expiry is mandatory; a separate watcher process fires the order when the condition is met and applies the same order-level rails as a market fill.

Architecture — Brain / Hands

The Brain (agents) only ever writes to disk; it holds no credentials. The Hands (the paper broker, a separate watcher process) reads that outbox, enforces the rails, and executes. The boundary is a directory of append-only JSONL files, so a real-money broker is a drop-in swap for the paper one behind the same contract.

flowchart LR
    A["Agents (Brain)"] -->|"author orders"| O["outbox/*.jsonl"]
    O --> B{"paper broker: safety rails"}
    B -->|"filled"| I["inbox/*.jsonl"]
    B -->|"rejected + reason code"| I
    I -->|"apply_trade"| P["portfolios/*.json"]
    A -.->|"conditional order"| PE["pending/order_id.json"]
    PE --> W["check_triggers watcher"]
    W -.->|"price level crossed"| B

Loading

Quickstart — reach a real fill

This drives the full loop end-to-end: bootstrap prices, hand-author two orders (one clears, one is deliberately oversized to trip a rail), run the broker, and inspect the fills.

python -m venv .venv && source .venv/bin/activate
pip install midas-core

# Materialise the packaged demo desk (roster.yaml, .claude/agents/demo-*.md,
# data/universes/*.json) into a directory you name — no git clone required.
midas init-demo ./my-desk
export MIDAS_DATA_DIR=$PWD/my-desk

# One-time: open a USD 10,000 portfolio for demo-momentum.
python -c "
from engine.config import get_config
from engine.portfolio import PortfolioManager
pm = PortfolioManager(base_dir=get_config().portfolios_dir)
pm.initialize('demo-momentum', initial_capital=10000, currency='USD')
"

# Bootstrap the price store from yfinance (the one networked step; the live desk
# populates this store from a cron so trading sessions stay HTTP-free).
midas fetch-ohlcv --symbols SPY,QQQ,IWM,VTV,SCHD,BRK-B,URTH --history-days 90

Author two orders — append-only JSONL, one per line — to $MIDAS_DATA_DIR/data/orders/outbox/<TODAY>.jsonl (<TODAY> = today's YYYY-MM-DD). Every field is required, including a non-empty reasoning (no silent trades); shares must be strictly positive (Midas is long-only):

{"order_id": "ord_demo_001", "ts": "2026-04-17T20:00:00Z", "agent_id": "demo-momentum", "action": "BUY", "ticker": "SPY", "shares": 3, "reasoning": "Trend intact above the 50-day; adding core exposure.", "currency": "USD"}
{"order_id": "ord_demo_002", "ts": "2026-04-17T20:00:00Z", "agent_id": "demo-momentum", "action": "BUY", "ticker": "SPY", "shares": 10, "reasoning": "Deliberately oversized clip to demonstrate the notional rail.", "currency": "USD"}

demo-momentum's max_order_notional is 5000. With SPY near $740 the first order ($2,200) clears; the second ($7,400) breaches the cap. Run the broker:

midas fill-day
# fill-day: 1 filled, 1 rejected out of 2

The inbox is the durable Hands-side record of both outcomes:

cat $MIDAS_DATA_DIR/data/orders/inbox/<TODAY>.jsonl

{"order_id": "ord_demo_001", "status": "filled",   "fill_price": 738.18, "notional_base": 2214.54, "fees": 1.25, "reason": null}
{"order_id": "ord_demo_002", "status": "rejected",  "fill_price": null,   "notional_base": null,    "fees": null, "reason": "MAX_ORDER_NOTIONAL"}

The filled order mutated data/portfolios/demo-momentum/portfolio.json (cash debited, a SPY position opened); the rejected one changed nothing but its reason. Exact prices depend on the day you fetch — the shape (one fill, one rejection, a debited portfolio) is the point.

The full walkthrough — the portfolio JSON, the executed_sha provenance stamp, and the roster schema — is in ./examples/demo-desk/README.md.

From source (contributors)

python -m venv .venv && source .venv/bin/activate
pip install -r requirements.txt   # pinned lockfile (incl. pytest + hypothesis)
pip install -e .                  # the midas-core package + the `midas` CLI

# Point the engine at a working copy of the demo desk.
cp -R examples/demo-desk /tmp/my-desk
export MIDAS_DATA_DIR=/tmp/my-desk

pytest -q

Run your own desk

The whole cast is config. Copy the demo desk and edit two things:

1. roster.yaml — declare your traders, a narrator, and an optional allocator, each with its universe, starting capital, and broker-enforced safety rails (max_order_notional, max_orders_per_day, daily_drawdown_halt_pct, allowed_universe).
2. .claude/agents/*.md — the persona behind each id: its voice and its strategy.

Nothing else is hardcoded. The full roster schema (every field and its default) is documented in ./examples/demo-desk/README.md.

What you need

To run…	Requirements
Deterministic pipeline — fills, baselines, backtests	Python 3.12+ only. No API keys, no accounts.
LLM trading sessions — personas, journals, narration	Runs under Claude Code (scripts/daily_session.py).

The deterministic pipeline is headless and fully tested; you can drive a desk end-to-end with no model at all by hand-authoring orders, exactly as the quickstart does.

Honest framing

• Paper-trading by default. Fills are simulated against a committed price store. No output is a track record, evidence of an edge, or investment advice.
• Framework, not a service. midas-core never executes against your broker keys, never holds credentials, never pools or manages anyone's funds, and gives no per-user advice. A real-money broker would be your code, swapped in behind the same outbox/inbox contract.
• Full terms: DISCLAIMER.md.

Relationship to the live desk

This repository is a one-way code mirror, synced from the operator's private live repo (the source of truth) by a manifest tool. The live desk's data ledger — its real portfolios, journals, and daily narrative — stays private and is not in this repo; the bundled examples/demo-desk is a synthetic fixture. Because of the mirror direction, code PRs against synced trees can't be merged — please open an issue instead. See CONTRIBUTING.md.

Layout

• engine/ — types, market data, bt adapter, paper broker, config (roster.yaml loader), universes.
• scripts/ — session orchestration (daily_session.py), the conditional-order watcher (check_triggers.py), backtest runners, universe refresh.
• examples/demo-desk/ — the forkable reference desk.
• data/{strategies,universes}/ — generic strategy specs + index constituents.

License

MIT.