custom-indicator — Codex skill: build technical indicators
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.
npx skills add marketcalls/openalgo-indicator-skills --skill custom-indicator -a claude-codeWhat custom-indicator 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.
What it helps with
- check whether
openalgo.taalready 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 for the agent
/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.
How to install custom-indicator
1Skills CLI (Vercel)
npx skills add marketcalls/openalgo-indicator-skills --skill custom-indicator -a claude-code2Manually: put the files in place
~/.claude/skills/custom-indicator/SKILL.mdCopy the whole skill folder; for one project use .claude/skills/custom-indicator/
1Skills CLI (Vercel)
npx skills add marketcalls/openalgo-indicator-skills --skill custom-indicator -a codex2Manually: put the files in place
.agents/skills/custom-indicator/SKILL.mdFor all projects use ~/.agents/skills/
1Skills CLI (Vercel)
npx skills add marketcalls/openalgo-indicator-skills --skill custom-indicator -a cursor2Manually: put the files in place
.cursor/skills/custom-indicator/SKILL.mdCursor also reads .agents/skills/ and .claude/skills/
1GitHub CLI
gh skill install marketcalls/openalgo-indicator-skills custom-indicator2Manually: put the files in place
.github/skills/custom-indicator/SKILL.md1Skills CLI (Vercel)
npx skills add marketcalls/openalgo-indicator-skills --skill custom-indicator -a gemini-cli2Platform CLI
gemini skills install https://github.com/marketcalls/openalgo-indicator-skills --path .claude/skills/custom-indicatorManually: put the files in place
.devin/skills/custom-indicator/SKILL.mdThe legacy .windsurf/skills/ path still works
Skills CLI (Vercel)
npx skills add marketcalls/openalgo-indicator-skills --skill custom-indicator -a opencodeClaude.ai
Zip the folder and upload it in Settings → Capabilities → Skills
Step by step, with commands for each platform: How to install skills in Claude Code: five ways
Questions about custom-indicator
How do I install custom-indicator in Codex?
Run npx skills add marketcalls/openalgo-indicator-skills --skill custom-indicator -a codex. The skill file is at .agents/skills/custom-indicator/SKILL.md.
What does custom-indicator do?
It checks openalgo.ta for an existing indicator and helps build a missing one with vectorized NumPy and ta primitives.
Which files does it prepare for a new indicator?
It creates a Python calculation file, chart.py for plotting, and benchmark.py for performance testing.
