Agent skill

Openalgo Chart Plugin

by marketcalls in marketcalls/openalgo-charts

Extend openalgo-charts with a custom primitive, drawing tool, chart type, or indicator descriptor.

Apache-2.0Auto-check: notes

Install Openalgo Chart Plugin

skills CLI

$ npx skills add marketcalls/openalgo-charts --skill openalgo-chart-plugin -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install marketcalls/openalgo-charts openalgo-chart-plugin --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/marketcalls/openalgo-charts.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.github/skills/openalgo-chart-plugin .claude/skills/openalgo-chart-plugin && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "openalgo-chart-plugin" agent skill from https://github.com/marketcalls/openalgo-charts/tree/master/.github/skills/openalgo-chart-plugin into .claude/skills/openalgo-chart-plugin/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "openalgo-chart-plugin", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/marketcalls/openalgo-charts/tree/master/.github/skills/openalgo-chart-plugin

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add marketcalls/openalgo-charts --skill openalgo-chart-plugin -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install marketcalls/openalgo-charts openalgo-chart-plugin --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/marketcalls/openalgo-charts.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.github/skills/openalgo-chart-plugin .agents/skills/openalgo-chart-plugin && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "openalgo-chart-plugin" agent skill from https://github.com/marketcalls/openalgo-charts/tree/master/.github/skills/openalgo-chart-plugin into .agents/skills/openalgo-chart-plugin/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "openalgo-chart-plugin", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add marketcalls/openalgo-charts --skill openalgo-chart-plugin -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install marketcalls/openalgo-charts openalgo-chart-plugin --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/marketcalls/openalgo-charts.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.github/skills/openalgo-chart-plugin .cursor/skills/openalgo-chart-plugin && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "openalgo-chart-plugin" agent skill from https://github.com/marketcalls/openalgo-charts/tree/master/.github/skills/openalgo-chart-plugin into .cursor/skills/openalgo-chart-plugin/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "openalgo-chart-plugin", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/marketcalls/openalgo-charts.git --path .github/skills/openalgo-chart-plugin

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add marketcalls/openalgo-charts --skill openalgo-chart-plugin -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install marketcalls/openalgo-charts openalgo-chart-plugin --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/marketcalls/openalgo-charts.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.github/skills/openalgo-chart-plugin .gemini/skills/openalgo-chart-plugin && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "openalgo-chart-plugin" agent skill from https://github.com/marketcalls/openalgo-charts/tree/master/.github/skills/openalgo-chart-plugin into .gemini/skills/openalgo-chart-plugin/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "openalgo-chart-plugin", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install marketcalls/openalgo-charts openalgo-chart-plugin

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add marketcalls/openalgo-charts --skill openalgo-chart-plugin -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/marketcalls/openalgo-charts.git skills-src && mkdir -p .github/skills && cp -r skills-src/.github/skills/openalgo-chart-plugin .github/skills/openalgo-chart-plugin && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "openalgo-chart-plugin" agent skill from https://github.com/marketcalls/openalgo-charts/tree/master/.github/skills/openalgo-chart-plugin into .github/skills/openalgo-chart-plugin/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "openalgo-chart-plugin", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add marketcalls/openalgo-charts --skill openalgo-chart-plugin -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install marketcalls/openalgo-charts openalgo-chart-plugin --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/marketcalls/openalgo-charts.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.github/skills/openalgo-chart-plugin .opencode/skills/openalgo-chart-plugin && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "openalgo-chart-plugin" agent skill from https://github.com/marketcalls/openalgo-charts/tree/master/.github/skills/openalgo-chart-plugin into .opencode/skills/openalgo-chart-plugin/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "openalgo-chart-plugin", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: openalgo-chart-plugin
GitHub stars: 144
Token cost: ~1.1k tokens
SKILL.md length: 467 words
Files: 1
Skills in repo: 6
Repo updated: Oct 1, 2026
First seen: Oct 7, 2026
Licence: Apache-2.0

At a glance

Extend openalgo-charts with a custom primitive, drawing tool, chart type, or indicator descriptor.

Works in 5 steps: pick the extension point → read the contract before writing → the rules that make it correct → …
The user wants a custom overlay
SKILL.md covers Step 1 - pick the extension…, Step 2 - read the contract…, Step 3 - the rules that make… and Step 4 - minimum viable…, plus 1 more section
Calls npx and rg

What it does

Openalgo Chart Plugin is an agent skill from marketcalls/openalgo-charts. Extend openalgo-charts with a custom primitive, drawing tool, chart type, or indicator descriptor. Use when the user wants a custom overlay, annotation, band, zone, marker layer, hand-drawn tool, or a series style the library does not ship.

Its SKILL.md is about 1.1k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

The repository describes itself as: Production-grade charts built for brokers, exchanges, trading platforms, and financial portals. Bring your own market data, plug it in, and deliver a complete charting experience… The licence is Apache-2.0.

When your agent uses it

The user wants a custom overlay
Hand-drawn tool
A series style the library does not ship

Example prompts

“/openalgo-chart-plugin”

Requirements

Node.js
Pre-approved tools (allowed-tools): Read, Write, Edit, Bash, Glob, Grep

Workflow steps

5 steps, taken from the step headings in SKILL.md.

pick the extension point
read the contract before writing
the rules that make it correct
minimum viable primitive
test it

What it can do on your machine

Read from SKILL.md and the folder at commit 8b4cffe. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves these tools, so the agent can use them without asking each time:
- Read
- Write
- Edit
- Bash
- Glob
- Grep
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
- npx
- rg
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use npx, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Openalgo Chart Plugin loads about 1.1k tokens when it runs. Until then it costs about 66 tokens; SKILL.md has 467 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~66
When it runs · the whole SKILL.md, loaded when a task matches: ~1.1k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check: notes

The automated check noted patterns worth knowing about, such as sudo or a known installer.

NotePre-approves every shell command (allowed-tools: Bash)SKILL.md
```
allowed-tools: Read, Write, Edit, Bash, Glob, Grep
```

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from marketcalls/openalgo-charts at commit 8b4cffe, republished under its Apache-2.0 licence (© marketcalls). 467 words, ~1,124 tokens.

Download SKILL.mdSave it as .claude/skills/openalgo-chart-plugin/SKILL.md (or your agent's skills folder).

name: openalgo-chart-plugin
description: Extend openalgo-charts with a custom primitive, drawing tool, chart type, or indicator descriptor. Use when the user wants a custom overlay, annotation, band, zone, marker layer, hand-drawn tool, or a series style the library does not ship.
allowed-tools: Read, Write, Edit, Bash, Glob, Grep
argument-hint: [what-to-build]

Extend the engine. Everything extensible in this library is a registry entry or a primitive - there is no plugin loader and no core file to edit.

Step 1 - pick the extension point

Answer these in order and stop at the first yes.

Question	Build
Does it need its own data, autoscale and price-scale identity?	a chart type via `registerChartType`
Is it a shape the user places with clicks and drags later?	a drawing tool via `registerDrawingTool`
Is it a number computed per bar that should get a pane, legend row and settings?	an indicator via `registerIndicator`
Anything else that draws - band, zone, label, watermark, custom axis marker	a primitive via `IPrimitive`

Default to a primitive. It is the cheapest and most flexible. Reach past it only when the table above says to.

Step 2 - read the contract before writing

Primitive and custom chart type: primitives-and-plugins
Drawing tool: drawing-tools
Indicator descriptor: indicators

Confirm the interface shape against local typings before writing an implementation:

rg -n "interface IPrimitive|interface RendererEntry|interface DrawingTool|interface IndicatorDescriptor" \
  node_modules/openalgo-charts/dist/index.d.ts node_modules/openalgo-charts/dist/draw/index.d.ts

Step 3 - the rules that make it correct

Draw in bitmap pixels. The canvas context is scaled to the device. Multiply every media-px value by ctx.dpr before you draw, or the result blurs and drifts on HiDPI displays. This is the single most common mistake.
Anchor in data space, not pixels. Store { time, price } and convert at draw time. The time axis is gapless, so a pixel anchor slides the moment a session gap collapses or the user zooms.
Pick the right z-order. 'bottom' draws behind the series, 'normal' over it on the base canvas, 'top' on the overlay canvas which repaints on cursor moves. Anything that follows the pointer belongs on 'top'; anything static does not, or you will repaint it on every mouse move.
autoscaleInfo runs every layout pass. Return a cheap precomputed extent; do not scan your data there.
Give hit-testable primitives a stable externalId. Clicks and drags route back to you through it.
Clean up in detached. Timers, subscriptions, cached bitmaps.
Register into the package entry, never a deep path. A deep import creates a second registry Map and your registration becomes invisible to createChart. See bundling-and-tiers.
Register before use. For a chart type, before the addSeries call that names it.
No emojis or icons in drawn text or logs.

Show full SKILL.md (82 more words)Show less

Step 4 - minimum viable primitive

import type { IPrimitive, PrimitiveRenderContext } from 'openalgo-charts';

class Band implements IPrimitive {
  constructor(private lo: number, private hi: number) {}
  zOrder() { return 'bottom' as const; }
  draw(g: CanvasRenderingContext2D, ctx: PrimitiveRenderContext) {
    const dpr = ctx.dpr;
    const y1 = ctx.priceScale.priceToY(this.hi) * dpr;
    const y2 = ctx.priceScale.priceToY(this.lo) * dpr;
    g.fillStyle = 'rgba(80,140,255,0.12)';
    g.fillRect(0, y1, ctx.plotWidth * dpr, y2 - y1);
  }
  autoscaleInfo() { return { min: this.lo, max: this.hi }; }
}

chart.addPrimitive(new Band(99, 101), 0);

Confirm every member name against the typings before shipping this shape - the reference file documents the interface, but dist/index.d.ts is authoritative.

Step 5 - test it

The repo's own tests are the pattern to copy. Look at tests/primitives.test.ts, tests/draw-tier.test.ts and tests/chart-types.test.ts for how a canvas-free unit test asserts draw calls and hit-testing. A plugin with no test is not done.

npx vitest run
npx tsc --noEmit

Report the extension point you chose and why, the file you created, and the test that covers it.

Files

Just SKILL.md in .github/skills/openalgo-chart-plugin of marketcalls/openalgo-charts.

Open the folder on GitHubat commit 8b4cffe

Compare with similar skills

Openalgo Chart Plugin next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Openalgo Chart Plugin compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Openalgo Chart Plugin this skillmarketcalls/openalgo-charts	144	—	~1.1k	Automated safety check: Notes	Apache-2.0	8 days ago
Chart Visualizationbytedance/deer-flow	84k	2 repos	~840	Automated safety check: Pass	MIT	today
Working With ChartsPostHog/posthog	40k	—	~948	Automated safety check: Pass	Custom licence	today
Chart Indicatormarketcalls/openalgo	2.8k	—	~8.7k	Automated safety check: Notes	AGPL-3.0	today
Helm Chartssickn33/agentic-awesome-skills	47k	1 repos	~2.6k	Automated safety check: Pass	MIT	today
Draw Iodavila7/claude-code-templates	32k	1 repos	~1.9k	Automated safety check: Pass	MIT	today

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Questions about Openalgo Chart Plugin

What does Openalgo Chart Plugin do?

Extend openalgo-charts with a custom primitive, drawing tool, chart type, or indicator descriptor. Openalgo Chart Plugin is an agent skill from marketcalls/openalgo-charts. Extend openalgo-charts with a custom primitive, drawing tool, chart type, or indicator descriptor.

When should I use Openalgo Chart Plugin?

Openalgo Chart Plugin fits situations like: the user wants a custom overlay; hand-drawn tool; A series style the library does not ship.

How do I install Openalgo Chart Plugin in Claude Code?

Run `npx skills add marketcalls/openalgo-charts --skill openalgo-chart-plugin -a claude-code`. Or copy the skill folder (.github/skills/openalgo-chart-plugin in marketcalls/openalgo-charts) into .claude/skills/openalgo-chart-plugin in your project. Claude Code loads it when a task matches its description.

How do I install Openalgo Chart Plugin in Codex?

Run `npx skills add marketcalls/openalgo-charts --skill openalgo-chart-plugin -a codex`. Or copy the skill folder (.github/skills/openalgo-chart-plugin in marketcalls/openalgo-charts) into .agents/skills/openalgo-chart-plugin in your project. Codex loads it when a task matches its description.

Can I use Openalgo Chart Plugin in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add marketcalls/openalgo-charts --skill openalgo-chart-plugin -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/openalgo-chart-plugin, .gemini/skills/openalgo-chart-plugin, .github/skills/openalgo-chart-plugin and .opencode/skills/openalgo-chart-plugin in your project.

What does Openalgo Chart Plugin need to run?

Going by SKILL.md and its folder, Openalgo Chart Plugin needs the command-line tools its instructions call (npx and rg). Our summary lists: Node.js. Its frontmatter pre-approves these tools: Read, Write, Edit, Bash, Glob, Grep.

Does Openalgo Chart Plugin access the network?

SKILL.md contains no URLs. Its commands use npx, which can reach the network depending on how they are called. This is read from the text; nothing was executed.

Is Openalgo Chart Plugin safe to install?

Our automated static check of SKILL.md found notes only (pre-approves every shell command (allowed-tools: bash)), nothing it rates as a warning. It is not a guarantee. Review the folder before installing.

What licence does Openalgo Chart Plugin use?

Openalgo Chart Plugin is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Openalgo Chart Plugin use?

About 1.1k tokens (SKILL.md is roughly 4.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Openalgo Chart Plugin?

Skills that share tags, products or a category with Openalgo Chart Plugin: Chart Visualization (bytedance/deer-flow, 84k stars), Working With Charts (PostHog/posthog, 40k stars), Chart Indicator (marketcalls/openalgo, 2.8k stars) and Helm Charts (sickn33/agentic-awesome-skills, 47k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Openalgo Chart Plugin?

marketcalls (a GitHub user) maintains it in marketcalls/openalgo-charts, which has 144 GitHub stars. The repository holds 6 skills in this directory. The repository was last updated on October 1, 2026.

Source: marketcalls/openalgo-charts on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Openalgo Chart Plugin

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Step 1 - pick the extension point

Step 2 - read the contract before writing

Step 3 - the rules that make it correct

Step 4 - minimum viable primitive

Step 5 - test it

Files

Compare with similar skills

Similar skills

More from marketcalls/openalgo-charts

Questions about Openalgo Chart Plugin