Trader – LLM agent for Robinhood with a Rust safety layer and paper trading

I built this after Robinhood launched their official agentic trading MCP server. The idea: give an LLM access to the Robinhood MCP tools (portfolio, quotes, order placement), but sit a typed Rust safety layer in the middle that hard-enforces risk limits regardless of what the model decides.

  The architecture is a ToolExecutor trait chain:

    LLM → SafetyValidator → ResearchExecutor →
  SimulationExecutor → Robinhood MCP

  Each layer is independent. The SafetyValidator checks
  every order against your
  config (stop-loss, position caps, per-trade USD cap,
  daily trade count, minimum
  cash reserve) and rejects violations before they reach
   the broker. The
  ResearchExecutor intercepts web_search and
  get_stock_news calls and satisfies
  them locally via Yahoo Finance RSS and Brave/DDG — no
  extra API key required for
  the news side. A new get_stock_fundamentals tool
  fetches the real 52-week high,
  volume ratio, and P/E from Yahoo Finance so the LLM
  evaluates buy filters on
  actual data instead of guessing.

  Strategy is defined in YAML as a hybrid: structured
  thresholds enforced by Rust
  plus free-text judgment rules passed verbatim to the
  LLM prompt. You can run
  multiple strategies in parallel, each on its own
  interval. Paper trading uses
  live Robinhood market data against a virtual portfolio
   persisted to disk, with an
  equity curve you can view as an ASCII chart in the TUI
   or export to CSV.

  The audit log writes one JSONL line per cycle with the
   full turn-by-turn
  conversation — system prompt, every tool call and
  result, intermediate LLM
  reasoning, final response — so you can replay and
  inspect exactly what the model
  was thinking.

  Works with any OpenAI-compatible endpoint. I've tested
   with GPT-4o, Claude,
  Groq's llama-3.3-70b (free tier), and locally with
  Ollama qwen2.5:7b. The
  7B local model is borderline for reliable tool
  calling; 14B+ is more consistent.

  The obvious caveat: this is paper-trading software
  that happens to also support
  live mode. I wouldn't run it live without significant
  time in simulation first.
  dry_run: true is the default and the safety layer
  still enforces everything in
  dry-run mode — it just blocks the final order from
  reaching Robinhood.