market_screener/README.md

# Market Screener

A personal stock screener and portfolio tracker. Scores stocks, ETFs, and bonds under two lenses — **Market-Adjusted** (what's acceptable in today's market) and **Fundamental** (strict Graham value-investing) — then compares them to produce an actionable signal. Comes with a live SvelteKit dashboard.

---

## Table of Contents

- [Developer Setup](#developer-setup)
- [Environment Variables](#environment-variables)
- [Commands](#commands)
- [Running Tests](#running-tests)
- [Project Structure](#project-structure)
- [User Guide](#user-guide)

---

## Developer Setup

### Prerequisites

- Node.js 20+
- npm 10+

### Install

```bash
# Install server dependencies
npm install

# Install UI dependencies (first time only)
npm run ui:install
```

### Start

```bash
npm run dev
```

This starts both the API server on **port 3000** and the SvelteKit UI on **port 5173** concurrently. Open [http://localhost:5173](http://localhost:5173).

To run the API server alone:

```bash
npm run server
```

---

## Environment Variables

Create a `.env` file in the project root. None are required to run the app — it works with Yahoo Finance data out of the box. Optional keys unlock additional features.

### `ANTHROPIC_API_KEY` — LLM news analysis *(optional)*

Powers the **Analyze** button on each screener section. Without this key the button is disabled.

1. Go to [console.anthropic.com](https://console.anthropic.com)
2. Create an API key under **API Keys**
3. Add to `.env`:

```env
ANTHROPIC_API_KEY=sk-ant-...
```

### `SIMPLEFIN_SETUP_TOKEN` — Live bank/brokerage balances *(optional)*

Powers the personal finance section of the Portfolio page (net worth, account balances, spending breakdown).

1. Go to [beta-bridge.simplefin.org](https://beta-bridge.simplefin.org) and create a Setup Token
2. Add to `.env`:

```env
SIMPLEFIN_SETUP_TOKEN=aHR0cHM6Ly...
```

On first request the token is claimed automatically and the resulting Access URL is saved back to `.env` as `SIMPLEFIN_ACCESS_URL`. Subsequent restarts use the Access URL directly.

### `API_KEY` — Bearer token auth *(optional)*

When set, every API route requires `Authorization: Bearer <key>`. Useful when the server is exposed to a network. `/health` and OPTIONS preflight are exempt.

```env
API_KEY=your-secret-key
```

### `CLIENT_ORIGIN` — CORS allowed origin *(optional)*

Defaults to `http://localhost:5173`. Change if the UI is served from a different origin.

```env
CLIENT_ORIGIN=https://yourdomain.com
```

### Complete `.env` example

```env
ANTHROPIC_API_KEY=sk-ant-...
SIMPLEFIN_SETUP_TOKEN=aHR0cHM6Ly...
API_KEY=optional-secret
CLIENT_ORIGIN=http://localhost:5173
```

---

## Commands

| Command | Description |
|---|---|
| `npm run dev` | Start API (port 3000) + UI (port 5173) together |
| `npm run server` | Start API server only |
| `npm run ui:install` | Install UI dependencies (first time / after `git pull`) |
| `npm test` | Run all unit + integration tests |
| `npm run test:watch` | Watch mode — re-run on file changes |
| `npm run typecheck` | TypeScript type check without emitting |
| `npm run format` | Format all source files with Prettier |
| `npm run format:check` | Check formatting without writing (used in CI) |

---

## Running Tests

```bash
npm test
```

Uses Node's built-in `node:test` runner — no external framework. Tests cover:

- Scoring rules and gate values (`ScoringConfig`, `RuleMerger`, `MarketRegime`)
- Asset scorers (`StockScorer`, `EtfScorer`, `BondScorer`)
- Data mapping (`DataMapper`)
- Portfolio advice logic (`PortfolioAdvisor`)
- LLM response parsing (`LLMAnalyst`)
- Repository CRUD (`MarketCallRepository`)
- Controller integration tests for all API routes (Fastify `inject()`, zero live network calls)

Pre-commit hook runs Prettier then tests. Pre-push hook runs tests.

---

## Project Structure

```
bin/
  server.ts              API server entry point

server/
  app.ts                 Fastify app factory — wires DI, rate limiting, auth hook
  controllers/           HTTP layer: parse request → call service → return response
  services/              Business logic (ScreenerEngine, BenchmarkProvider, PortfolioAdvisor…)
  repositories/          JSON file persistence (MarketCallRepository, PortfolioRepository)
  clients/               External API connectors (YahooFinanceClient, SimpleFINClient, AnthropicClient)
  models/                Domain entities: Stock, Etf, Bond
  scorers/               Stateless scoring functions: StockScorer, EtfScorer, BondScorer
  config/                ScoringConfig (all gates/weights), constants
  types/                 TypeScript interfaces, one file per domain

ui/
  src/
    routes/              SvelteKit pages: /, /portfolio, /calls, /safe-buys
    lib/
      stores/            Svelte 5 reactive stores (screener.store, portfolio.store)
      api/               Fetch wrappers for each API domain
      portfolio/         Portfolio-specific components
      calls/             Market calls components
    styles/              Global SCSS design tokens and partials

tests/                   Unit + integration tests

portfolio.json           Your holdings (gitignored — create manually or via the UI)
market-calls.json        Persisted market thesis calls (gitignored)
.benchmark-cache.json    Benchmark data cache — survives server restart (gitignored)
```

---

## User Guide

### Screener tab

The main view. On load it automatically fetches today's financial news, extracts the most-mentioned tickers, and screens them.

#### Market context strip

The row of chips at the top shows live benchmark data fetched from Yahoo Finance:

| Chip | Meaning |
|---|---|
| 10Y | 10-year Treasury yield — the risk-free rate |
| VIX | Volatility index — market fear gauge |
| S&P | S&P 500 index price |
| S&P P/E | Trailing P/E of the S&P 500 (via SPY) |
| Tech P/E | Trailing P/E of the tech sector (via XLK) |
| REIT Yld | REIT dividend yield (via XLRE) |
| IG Sprd | Investment-grade bond spread above risk-free (LQD − TNX) |
| Rates | Rate regime: LOW / NORMAL / HIGH (based on 10Y yield) |
| Vol | Volatility regime: LOW / NORMAL / HIGH (based on VIX) |

The rate regime affects how strict the Market-Adjusted gates are — in a HIGH rate environment the P/E multiplier compresses and bond spreads tighten.

#### Signal Summary table

Quick overview of all screened tickers with their signal, market-adjusted verdict, fundamental verdict, market cap tier, and growth style.

#### Per-asset detail tables

Expand each section (STOCK / ETF / BOND) for full metrics: P/E, PEG, ROE, margins, FCF yield, D/E, analyst consensus, DCF intrinsic value, 52-week movement, and more.

#### Analyze button

Runs an Anthropic LLM over the latest Yahoo Finance news for assets in that section. Returns a sentiment summary, affected industries, and related tickers to watch. Requires `ANTHROPIC_API_KEY`.

#### Search tickers

Click **Search tickers** to screen any custom list — type tickers comma or space separated and press Enter or click Screen.

#### Signals explained

| Signal | What it means |
|---|---|
| ✅ Strong Buy | Passes both Market-Adjusted AND Fundamental gates — genuine value at current prices |
| ⚡ Momentum | Passes Market-Adjusted, holds fundamentally — good in the current market but not a bargain |
| ⚠️ Speculation | Passes Market-Adjusted, fails Fundamental — priced for perfection, high risk |
| 🔄 Neutral | Borderline in one or both lenses — hold, no clear edge |
| ❌ Avoid | Fails both lenses |

#### How scoring works

Every asset is scored twice:

**Market-Adjusted** gates move with the market. The stock P/E gate = SPY trailing P/E × 1.5 (compresses to × 1.2 in a HIGH rate regime). Tech P/E = XLK P/E × 1.3. This reflects what the market is currently willing to pay.

**Fundamental** gates are fixed Graham/value-investing standards that never change:

| Gate | Threshold | Rationale |
|---|---|---|
| Stock P/E | < 15× | Graham's actual rule |
| Stock PEG | < 1.0 | Lynch: PEG > 1.0 = paying full price |
| D/E ratio | < 1.5× | Distress typically starts above 2× |
| Quick ratio | > 0.8 | Below 0.8 = real liquidity stress |

Sector overrides apply in both modes — e.g. tech stocks allow P/E up to 35× and D/E up to 2.0, REITs are scored on yield rather than P/E.

---

### Portfolio tab

Track your holdings and get hold/sell/add advice cross-referenced with screener signals.

**Adding holdings** — click **+ Add Holding** and fill in ticker, shares, cost basis, asset type, and source broker. Holdings are saved to `portfolio.json` on disk.

**Inline editing** — click the ✎ pencil icon on any row to edit shares, cost basis, type, or source directly in the table.

**Advice column** — each holding is screened live and the signal is combined with your gain/loss position:

| Situation | Advice |
|---|---|
| ✅ Strong Buy signal | Hold & Add |
| ⚡ Momentum + > 30% gain | Consider partial profit-taking |
| ⚠️ Speculation + > 20% gain | Reduce position |
| ❌ Avoid signal + in profit | Sell (Take Profits) |
| ❌ Avoid signal + at a loss | Sell (Cut Loss) |
| Crypto | Hold / Review position (no fundamental scoring) |

**Personal finance section** *(requires SimpleFIN)* — when configured, the page also shows net worth, total assets vs liabilities, cash vs investments ratio, monthly income/spend, account balances, and a spending breakdown by category for the last 30 days.

---

### Market Calls tab

Record and track quarterly investment theses from the day you make the call.

**Creating a call** — click **＋ New Call** and fill in:
- **Title** — e.g. "Q3 2025 — Rate pivot & tech rotation"
- **Quarter** — the quarter this thesis applies to
- **Thesis** — the macro reasoning behind the call (min 10 characters)
- **Tickers** — the assets you're watching for this thesis

When saved, the current price and signal for each ticker are snapshotted automatically.

**Viewing performance** — click any call card to see the current price and signal for each ticker alongside the original snapshot, so you can measure how the thesis played out.

**Calendar** — shows upcoming earnings dates, ex-dividend dates, and dividend payment dates for all tickers across your active calls.

---

### Safe Buys tab

A filtered view showing only tickers with a **✅ Strong Buy** signal across both lenses. A quick watchlist of assets passing the strictest criteria in the current market.

---

### API rate limits

`/api/screen`, `/api/screen/catalysts`, and `/api/analyze` are capped at **10 requests per minute** per IP. All other routes allow 60 per minute.