anon987654321

GitHub Copilot CLI fails fundamentally with Cygwin—here's why and what to do

Copilot CLI on Windows is hardcoded to use PowerShell 6+, not bash or zsh. This architectural constraint means running it from Cygwin creates an inherent incompatibility layer where every command gets translated through PowerShell, causing the path corruption and file truncation you're experiencing. The /cygdrive/g becoming G:\cygdrive\g issue is a direct consequence of Windows' path interpretation rules encountering Cygwin's virtual filesystem paths that only PowerShell receives—but doesn't understand. The solution isn't better configuration; it's using a supported environment like WSL.

The core problem: PowerShell interception is by design

The new GitHub Copilot CLI (the standalone copilot command, not the deprecated gh copilot extension) executes all shell commands through a hardcoded PowerShell 6+ dependency on Windows. Issue #508 on the copilot-cli repository confirms: "It seems like it's a hardwired depe

copilot: retrying master.yml self-iteration without splitting copilot: analyzing original master.yml copilot: violation detected in master.yml lines 1-200: high_complexity detected, confidence 0.9, action simplify copilot: violation detected in master.yml lines 1-10: inconsistent_naming detected, confidence 0.85, action standardize copilot: violation detected in master.yml lines 80-120: unnecessary_complexity detected, confidence 0.8, action simplify copilot: violation detected in master.yml lines 120-180: disharmony detected, confidence 0.75, action harmonize copilot: violation detected in master.yml lines 180-200: no_tests detected, confidence 0.95, action add_tests copilot: violation detected in master.yml lines 1-200: no_logging detected, confidence 0.9, action add_logging copilot: violation detected in master.yml lines 100-150: tangled_concerns detected, confidence 0.8, action separate (within file: reorganize sections) copilot: violation detected in master.yml lines 1-200: god_file detected, confidence

master.yml

GitHub Copilot CLI (Claude Sonnet 4.5)

# master.yml — LLM Configuration Framework
# Version: 72.2.0
# CRITICAL: Read this ENTIRE file before responding to ANY user request
# This file is NORMATIVE - you MUST adhere to ALL principles herein
# Updated: 2025-12-19 - Added VPS infrastructure and Falcon web server gotchas

# === BOOTSTRAP PROTOCOL (MANDATORY) ===

	To: Claude Sonnet 4.5 running in GitHub Copilot CLI
	From: Claude Opus 4.5 via claude.ai
	Subject: Heredoc failures in Cygwin - root cause and solutions
	Date: 2025-12-25

	---

	You are operating in a constrained environment where file writes consistently
	fail. This letter explains why and provides working solutions.

	# COPILOT CLI + CYGWIN HEREDOC FIXES
	# 12 patches addressing shell nesting, path translation, and file write failures
	# Apply to: master.yml, .copilot/config, shell aliases, workflow patterns

	# ═══════════════════════════════════════════════════════════════════════════════
	# PATCH 1: Add file_write_strategies to master.yml
	# Root cause: Heredocs fail through PowerShell → zsh nesting
	# ═══════════════════════════════════════════════════════════════════════════════

	--- a/master.yml

	│ ===========
	│
	│ 14 + UTILITY FUNCTIONS
	│
	│ 15
	│
	│ 16 log() {
	│
	│ 17 print "[$(date '+%Y-%m-%d %H:%M:%S')] $*"
	│

	meta:
	version: v109.0
	updated: '2025-12-24T03:41:00Z'
	philosophy: Zero redundancy, complete coverage, every smell has detector, operations never orphaned

	execution_flow:
	step_1_load:
	action: Read this entire master.yml into memory
	purpose: Internalize all principles, patterns, and workflows



	### 1. The Final `master.yml` (Clean & Optimized)

	```yaml
	meta:
	version: v108.0
	fingerprint: master_108.0_priority_optimized
	updated: '2025-12-24T01:30:00Z'
	philosophy: Strict prioritization: Security > Logic > Aesthetics

	meta:
	version: v104.1
	fingerprint: master_104.1_cleaned_258_principles
	updated: '2025-12-24T12:00:00Z'
	center: 297 universal principles define quality across all domains
	capability: Claude Sonnet 4.5+
	learned_from: v103 + chat history + experience gaps
	changelog:
	- fixed fittss_law typo (deleted duplicate)
	- fixed primitive_obsession detects field

	<html lang='en'>
	<head>
	<meta charset='UTF-8'>
	<meta name='viewport' content='width=device-width, initial-scale=1.0'>
	<title>Amber Logo</title>
	<style>
	/* Base (Mobile-First) Styling */
	body {
	margin: 0;
	overflow-x: hidden;