How is colorLevel determined?

If isTTY and NO_COLOR is not set, colorLevel is set to 3 for truecolor, 2 for 256-color, or 1 for basic color if TERM is set (and not dumb).

How is Unicode support detected on Windows?

Unicode is considered supported on Windows if WT_SESSION is set or if the TERM_PROGRAM indicates a VSCode environment, otherwise falls back to non-Unicode behavior.

What if terminal size is unavailable?

Columns default to 80 and rows default to 24, with values sourced from process.stdout when available.

terminal-capability-detector

npx machina-cli add skill a5c-ai/babysitter/terminal-capability-detector --openclaw

Files (1)

SKILL.md

1.6 KB

Terminal Capability Detector

Detect terminal capabilities for adaptive CLI output.

Capabilities

Detect color support levels
Check TTY status
Get terminal dimensions
Detect Unicode support
Check for CI environment
Configure adaptive output

Generated Patterns

import process from 'process';
import tty from 'tty';

export interface TerminalCapabilities {
  isTTY: boolean;
  colorLevel: 0 | 1 | 2 | 3;
  supportsUnicode: boolean;
  columns: number;
  rows: number;
  isCI: boolean;
}

export function detectCapabilities(): TerminalCapabilities {
  const isTTY = tty.isatty(1);
  const isCI = Boolean(process.env.CI || process.env.CONTINUOUS_INTEGRATION);

  let colorLevel: 0 | 1 | 2 | 3 = 0;
  if (isTTY && !process.env.NO_COLOR) {
    if (process.env.COLORTERM === 'truecolor') colorLevel = 3;
    else if (process.env.TERM?.includes('256color')) colorLevel = 2;
    else if (process.env.TERM && process.env.TERM !== 'dumb') colorLevel = 1;
  }

  const supportsUnicode = process.platform !== 'win32' ||
    process.env.WT_SESSION ||
    process.env.TERM_PROGRAM === 'vscode';

  return {
    isTTY,
    colorLevel,
    supportsUnicode,
    columns: process.stdout.columns || 80,
    rows: process.stdout.rows || 24,
    isCI,
  };
}

Target Processes

cross-platform-cli-compatibility
cli-output-formatting
progress-status-indicators

Source

git clone https://github.com/a5c-ai/babysitter/blob/main/plugins/babysitter/skills/babysit/process/specializations/cli-mcp-development/skills/terminal-capability-detector/SKILL.md

View on GitHub

Overview

This skill detects terminal capabilities to drive adaptive CLI output. It exposes a detectCapabilities() function that returns isTTY, colorLevel, supportsUnicode, columns, rows, and isCI, enabling responsive formatting.

How This Skill Works

It uses Node's process and tty APIs to determine if stdout is a TTY and reads environment variables (NO_COLOR, COLORTERM, TERM) to set colorLevel. It also infers Unicode support on Windows via WT_SESSION or VSCode terminals, and reads terminal dimensions from process.stdout.columns and process.stdout.rows, with sensible fallbacks. A CI environment is detected via CI or CONTINUOUS_INTEGRATION variables.

When to Use It

Build a colorized CLI that adapts to terminal capabilities
Detect and adapt behavior when running in CI environments
Adjust output layout based on terminal size (columns/rows)
Enable Unicode glyphs for richer UI on capable terminals
Ensure consistent behavior across Windows and Unix-like shells

Quick Start

Step 1: import detectCapabilities from the skill module
Step 2: const cap = detectCapabilities();
Step 3: use cap.isTTY, cap.colorLevel, cap.columns, cap.rows, cap.supportsUnicode, and cap.isCI to drive output

Best Practices

Check isTTY before enabling color output to avoid spoilers in non-interactive shells
Honor NO_COLOR and avoid forcing color in CI environments
Fallback to 80x24 when terminal size is unavailable
Respect TERM hints (256color, truecolor) to maximize color depth when possible
Gracefully degrade Unicode usage on terminals that do not support it

Example Use Cases

Dynamic progress bars and colored status messages that adapt to colorLevel
Unicode-based UI elements (icons, symbols) on capable terminals
Responsive layouts that reflow content based on columns
Silent operation in CI by disabling interactive features
Cross-platform output with appropriate fallbacks for Windows and Unix shells

Frequently Asked Questions

Add this skill to your agents