agent-supply-chain

Agent Supply Chain

Verify that agent plugins, skill bundles, and MCP packages have not drifted between review, testing, and deployment.

When to Use

• Before promoting an agent plugin or MCP bundle from dev to staging or production
• When reviewing third-party skills, plugins, or local MCP servers before adoption
• When a repository needs deterministic integrity evidence instead of "looks unchanged"
• When dependency pinning and manifest checks should become part of a release gate

When NOT to Use

Instead of agent-supply-chain	Use
Generic codebase vulnerability review	security-scan
Repository-wide trust scoring and hygiene review	evaluate-repository
GitHub Actions workflow exploit review	gha-security-review

Workflow

1. Define the review boundary

Decide exactly what should be covered by the integrity check:

• the plugin or skill directory itself
• its manifest files
• related config such as .mcp.json, package.json, requirements.txt
• any local action or helper scripts that ship with the package

Exclude generated artifacts and cache directories so the manifest stays deterministic.

2. Generate a deterministic manifest

Create an INTEGRITY.json file with SHA-256 hashes for every tracked source file.

$root = "path\\to\\plugin"
$excludeDirs = @(".git", "node_modules", "__pycache__", ".venv", ".pytest_cache")
$excludeFiles = @("INTEGRITY.json", ".DS_Store", "Thumbs.db")

$files = Get-ChildItem -Path $root -Recurse -File |
  Where-Object {
    $relative = $_.FullName.Substring((Resolve-Path $root).Path.Length + 1)
    -not ($excludeFiles -contains $_.Name) -and
    -not ($excludeDirs | Where-Object { ($relative -split '[\\/]') -contains $_ })
  } |
  Sort-Object FullName

$manifestFiles = @{}
foreach ($file in $files) {
  $relative = $file.FullName.Substring((Resolve-Path $root).Path.Length + 1).Replace('\', '/')
  $hash = (Get-FileHash -Algorithm SHA256 -LiteralPath $file.FullName).Hash.ToLower()
  $manifestFiles[$relative] = $hash
}

$chain = [System.Security.Cryptography.SHA256]::Create()
$joined = ($manifestFiles.Keys | Sort-Object | ForEach-Object { $manifestFiles[$_] }) -join ""
$manifestHash = [Convert]::ToHexString($chain.ComputeHash([System.Text.Encoding]::UTF8.GetBytes($joined))).ToLower()

$manifest = [ordered]@{
  plugin_name = Split-Path $root -Leaf
  generated_at = (Get-Date).ToUniversalTime().ToString("o")
  algorithm = "sha256"
  file_count = $manifestFiles.Count
  files = $manifestFiles
  manifest_hash = $manifestHash
}

$manifest | ConvertTo-Json -Depth 5 | Set-Content -LiteralPath (Join-Path $root "INTEGRITY.json")