Mean reversion works best in grinding bull tape; stress-test 2008, 2020, and inflation-shock windows before trusting it.
Conversational quant backtesting agent system
ORACLE LOOP
A living Playground workbench where David can describe trading ideas in chat, then Hermes updates deterministic strategy DSL, cached-data manifests, simulation outputs, critiques, and UI visualization artifacts.
The LLM is allowed to be wrong. The execution system is not.
Seeded demo artifact
Buy SPY when RSI < 30, hold 5 trading days.
- Data
- SPY · 1d
- Cache
- cached_only_demo
- Hash
- spy-1d-demo-v0-e8b7c2
Overlay equity curve
7 strategiesTrade distribution
<-5%
2
-5–0%
11
0–2%
8
2–5%
7
>5%
3
Robustness critique
RSI 25/30/35 and hold 3/5/8 days should be swept; a single threshold is a belief, not evidence.
Demo run uses a seeded cached artifact. Production runs should pin provider, hash, adjustment policy, and missing-bar count.
Architecture
Messy language stops at a strict compiler boundary.
Natural language
LLM surface
Ambiguity is allowed but must be surfaced before execution.Hallucinated indicators, missing exit, contradictory sizing.Strategy DSL
Compiler boundary
Strict JSON, normalized defaults, schema-complete fields.Invalid JSON is repaired or rejected before data touches the kernel.Cached data layer
Rate-limit governor
Never fetch the same symbol/timeframe twice; prefer disk cache over APIs.Cached-only mode if free providers throttle or return partial data.Deterministic kernel
Execution core
No LLM, no network, no randomness unless explicitly seeded.Reject lookahead, centered windows, undefined indicators, impossible fills.Report + critique
Human loop
Metrics and curves are computed; interpretation is isolated commentary.Overfit warnings, regime sensitivity, and parameter fragility are shown.Algorithm
How a chat idea becomes a reproducible backtest.
Turn chat into a falsifiable contract
The agent converts the idea into a strict Strategy DSL: assets, timeframe, indicator windows, entry rules, exit rules, sizing, and fees. Missing or ambiguous fields are completed deterministically or rejected before execution.
Reject impossible or leaky rules
The compiler checks indicator vocabulary, rolling-window validity, lookahead risk, fill timing, exit coverage, and contradictory logic. This is where hallucinated indicators die.
Resolve data through cache manifests
Every symbol/timeframe request checks memory, disk cache, and immutable dataset chunks before any external fetch. Overlapping requests coalesce into one provider call.
Run a deterministic vector engine
Signals are shifted to avoid future leakage, fills apply fees/slippage assumptions, position sizing follows the DSL, and the kernel computes trades, returns, exposure, turnover, drawdown, and equity.
Attack the belief, not the spreadsheet
The report tests whether the result survives regime splits, parameter sweeps, missing-data flags, and overfit warnings. LLM commentary can interpret results but never computes them.
Strict output contract
Strategy DSL is the handshake between chat and execution.
Future chat updates should edit the data artifact first, then let this route render the compiled hypothesis, data manifest, deterministic metrics, and critique.
{
"strategy_name": "rsi_mean_reversion",
"assets": [
"SPY"
],
"timeframe": "1d",
"entry_rules": [
{
"indicator": "rsi",
"window": 14,
"operator": "<",
"value": 30
}
],
"exit_rules": [
{
"type": "time_hold",
"days": 5
}
],
"position_sizing": "all_in",
"fees": 0.001
}Compiler guardrails
The execution system is allowed to reject the LLM.
- No lookahead: signals can only use bars available before the simulated fill.
- No undefined indicators: RSI, SMA, EMA, breakout, volatility, and time-hold are the initial allowed vocabulary.
- No impossible exits: every strategy must include a time, signal, stop, or target exit rule.
- No silent data holes: partial histories mark the run as biased instead of backfilling fantasy prices.
- No repeated fetches: data requests resolve through symbol/timeframe/source/hash manifests.
Cache hierarchy
Coalesce repeated in-chat requests.
Reusable symbol/timeframe history.
Immutable chunk hashes for reproducibility.
Yahoo/Stooq/FRED fallback fetch only for missing segments.