# custom-indicator

This skill helps create a custom technical indicator with NumPy and openalgo.ta primitives. Use it when the calculation you need is not already available in the library.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 563 installs · ★ 18
- Author: marketcalls
- License: not stated · policy=link-only · description only; the file stays with the author
- Source: https://github.com/marketcalls/openalgo-indicator-skills/tree/HEAD/.claude/skills/custom-indicator/SKILL.md
- Updated: 2026-06-12
- HTML: https://affpapa.org/en/nevibecode/skills/custom-indicator

## What it does

The skill checks `openalgo.ta` first and points to the existing API if it finds the requested indicator. For a new one, it prepares a directory under `custom_indicators/{indicator_name}/` with a Python implementation, a Plotly chart script, and a performance benchmark.

The calculation uses `ta` primitives alongside vectorized NumPy expressions, with masks for NaN values and zero denominators. Numeric arrays use `float64`, and the algorithm is required to be O(n). Check that the project has the indicator rules the skill relies on before running it. The chart template also imports `plotly`, `dotenv`, and `openalgo.api`.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add marketcalls/openalgo-indicator-skills --skill custom-indicator -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/custom-indicator/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/custom-indicator/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add marketcalls/openalgo-indicator-skills --skill custom-indicator -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/custom-indicator/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add marketcalls/openalgo-indicator-skills --skill custom-indicator -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/custom-indicator/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install marketcalls/openalgo-indicator-skills custom-indicator
```

2. **Manually: put the files in place**
- File: `.github/skills/custom-indicator/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add marketcalls/openalgo-indicator-skills --skill custom-indicator -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/marketcalls/openalgo-indicator-skills --path .claude/skills/custom-indicator
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/custom-indicator/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add marketcalls/openalgo-indicator-skills --skill custom-indicator -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/marketcalls/openalgo-indicator-skills/tree/HEAD/.claude/skills/custom-indicator/SKILL.md

## When to use it
- check whether `openalgo.ta` already has an indicator
- build a vectorized calculation for a new indicator
- prepare a Plotly chart for indicator values
- benchmark calculations on arrays of different sizes

## Example prompts
- \`/custom-indicator zscore` — build a Z-Score calculation and check for an existing API first.
- \`/custom-indicator squeeze-momentum` — prepare the indicator, chart, and benchmark files.
- \`/custom-indicator vwap-bands` — create a calculation for bands around VWAP.

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From the same set: [marketcalls/openalgo-indicator-skills](https://affpapa.org/en/nevibecode/by/marketcalls/openalgo-indicator-skills.md) — 2 cards

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md