Description

Running npm run lint:frontmatter in a fresh devcontainer fails with:

❌ ConvertFrom-Yaml cmdlet not found. Install powershell-yaml module: Install-Module -Name PowerShell-Yaml -Force -Scope CurrentUser

Root Cause

Validate-MarkdownFrontmatter.ps1 requires the powershell-yaml PowerShell module to parse YAML frontmatter, but the devcontainer setup scripts do not install it. Neither on-create.sh nor post-create.sh include a powershell-yaml module installation step.

The copilot-setup-steps.yml workflow installs PowerShell-Yaml for the Copilot Coding Agent environment, but this is not mirrored in the local devcontainer setup.

Reproduction

1. Open hve-core in a fresh codespace or devcontainer
2. Run npm run lint:frontmatter
3. Observe the error

Suggested Fix

Add powershell-yaml installation to .devcontainer/scripts/on-create.sh or post-create.sh:

echo "Installing PowerShell-Yaml module..."
pwsh -NoProfile -Command "Install-Module -Name powershell-yaml -Force -Scope CurrentUser -Repository PSGallery"

Workaround

pwsh -NoProfile -Command "Install-Module -Name powershell-yaml -Force -Scope CurrentUser -Repository PSGallery"

Related Issues

• bug: npm run lint:ps fails when logs/ directory does not exist #497 — logs/ directory missing in fresh devcontainer
• bug: npm run lint:yaml fails — actionlint not installed in devcontainer #498 — actionlint not installed in devcontainer

All three issues stem from the same gap: the devcontainer lifecycle scripts do not install all tools required by npm run lint:all.

Affected Scripts

• scripts/linting/Validate-MarkdownFrontmatter.ps1
• .devcontainer/scripts/on-create.sh (missing installation)

Environment

• DevContainer on Ubuntu 24.04
• PowerShell 7.5.4
• Node.js 24.x