license-auditor

name	license-auditor
source	botcore
description	Performs OSS license compliance audits, dependency license analysis, and SBOM generation. Covers license categorization (permissive, copyleft, public domain), compatibility matrices, per-ecosystem audit tooling (Node.js, Python, Go), CI/CD license gate integration, required attribution files, and red-flag detection. Use when adding dependencies, auditing existing licenses, checking compatibility, generating SBOMs, preparing for release, or setting up license enforcement in CI. Triggers: license, licensing, OSS compliance, SBOM, GPL, MIT, Apache, copyleft, dependency audit, license check, attribution, SPDX, CycloneDX, bill of materials.
version	1.0.0
triggers	["license","licensing","OSS compliance","SBOM","GPL","MIT","Apache","copyleft","dependency audit","license check","attribution","SPDX","CycloneDX","bill of materials","permissive license","license compatibility"]
portable	true

License Auditing

Expert guidance for open-source license compliance, dependency auditing, and software bill of materials generation.

Capabilities

1. Categorize licenses -- Classify dependencies as permissive, weak copyleft, strong copyleft, or public domain and assess commercial-use risk
2. Audit dependency licenses -- Run per-ecosystem audit commands (Node.js, Python, Go) to enumerate and validate licenses across a project
3. Evaluate compatibility -- Determine whether combining libraries under different licenses is legally safe for the target project license
4. Generate SBOMs -- Produce CycloneDX, SPDX, or Syft-based Software Bills of Materials for release artifacts
5. Enforce in CI/CD -- Set up automated license-check and SBOM-generation gates in GitHub Actions or other pipelines
6. Detect red flags -- Identify GPL in proprietary code, missing license files, UNLICENSED packages, and license mismatches
7. Manage attribution files -- Ensure LICENSE, NOTICE, and THIRD-PARTY-LICENSES files are correct and complete

Core Principles

1. Know Before You Add

Every new dependency must have its license identified and categorized before merging. Unknown or missing licenses are blockers, not warnings.

2. Compatibility Over Convenience

A useful library under an incompatible license is not usable. Always check the compatibility matrix against your project's license before adoption.

3. Automate Enforcement

Manual license checks do not scale. Integrate license-checker or equivalent tools into CI so violations are caught on every pull request.

4. SBOM as Release Artifact

Every release should include a machine-readable SBOM (CycloneDX or SPDX). Treat it as a required build output, not optional documentation.

5. Attribution Is Non-Negotiable

Permissive licenses still require attribution. Maintain NOTICE and THIRD-PARTY-LICENSES files and keep them current with every dependency change.

Quick Reference

License Categories

Category	Examples	Commercial Use
Permissive	MIT, Apache-2.0, BSD-2, BSD-3, ISC	Safe
Weak Copyleft	LGPL-2.1, LGPL-3.0, MPL-2.0	Safe if dynamically linked; modifications to the library must be shared
Strong Copyleft	GPL-2.0, GPL-3.0, AGPL-3.0	Derivative work must use the same license
Public Domain	Unlicense, CC0-1.0, 0BSD	Safe
No License / UNLICENSED	--	Cannot use; all rights reserved by default

Common Licenses at a Glance

License	Key Requirements	Compatibility Notes
MIT	Include copyright + license text	Most permissive; compatible with nearly everything
Apache-2.0	Attribution + patent grant + NOTICE file	Permissive; incompatible with GPL-2.0 (compatible with GPL-3.0)
BSD-3-Clause	Attribution; no endorsement clause	Permissive; broadly compatible
LGPL-2.1/3.0	Dynamic linking OK; share modifications to library	Safe for proprietary apps if linked dynamically
MPL-2.0	File-level copyleft; modified files must be shared	Compatible with Apache-2.0 and GPL
GPL-2.0/3.0	All derivative work must be GPL	Viral; output project becomes GPL
AGPL-3.0	GPL + network interaction triggers distribution	Very viral; SaaS use triggers copyleft

Compatibility Matrix

Your Project License	Can Safely Use
MIT	MIT, BSD, ISC, Apache-2.0, Public Domain
Apache-2.0	MIT, BSD, ISC, Apache-2.0, Public Domain
GPL-3.0	Anything (but output is GPL-3.0)
Proprietary	MIT, BSD, ISC, Apache-2.0, LGPL (dynamic link), MPL (file-level), Public Domain

Workflow

License Audit Protocol

1. Enumerate Dependencies

Run ecosystem-specific commands to list all dependency licenses.

# Node.js
npx license-checker --summary
npx license-checker --csv --out licenses.csv

# Python
pip-licenses --format=markdown
pip-licenses --format=json --output-file licenses.json

# Go
go-licenses report ./...
go-licenses csv ./...

2. Validate Against Allowlist

Fail the check if any dependency uses a license outside the approved list.

# Node.js -- fail on anything not in allowlist
npx license-checker --onlyAllow "MIT;Apache-2.0;BSD-2-Clause;BSD-3-Clause;ISC;0BSD;Unlicense;CC0-1.0"

# Python -- fail on copyleft
pip-licenses --fail-on="GPL-2.0-only;GPL-3.0-only;AGPL-3.0-only"

3. Check for Red Flags

Issue	Risk Level	Action
GPL/AGPL in proprietary app	Critical	Remove dependency or replace with permissive alternative
AGPL in SaaS backend	Critical	Remove dependency or open-source the service
No license file in dependency	High	Contact author or find alternative; cannot assume permissive
UNLICENSED in package.json	High	Cannot use; all rights reserved
License field mismatch (package.json vs LICENSE file)	Medium	Verify actual license at source repository
Transitive dependency with copyleft	Medium	Audit full dependency tree, not just direct deps

4. Generate SBOM

# CycloneDX -- Node.js
npx @cyclonedx/cyclonedx-npm --output-file sbom.cdx.json

# CycloneDX -- Python
cyclonedx-py environment --output sbom.cdx.json

# SPDX -- universal via Syft
syft . -o spdx-json > sbom.spdx.json

# CycloneDX -- universal via Syft
syft . -o cyclonedx-json > sbom.cdx.json

5. Verify Attribution Files

Ensure the following files exist and are up to date.

File	Purpose	When Required
LICENSE	Your project's license	Always
NOTICE	Third-party attributions	Required by Apache-2.0; recommended for all
THIRD-PARTY-LICENSES	Full license texts of dependencies	Recommended for distribution

6. Integrate into CI/CD

# GitHub Actions example
name: license-auditor
on: [pull_request]

jobs:
  license-check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Install dependencies
        run: npm ci

      - name: License allowlist check
        run: npx license-checker --onlyAllow "MIT;Apache-2.0;BSD-2-Clause;BSD-3-Clause;ISC;0BSD;Unlicense;CC0-1.0"

      - name: Generate SBOM
        run: npx @cyclonedx/cyclonedx-npm --output-file sbom.cdx.json

      - name: Upload SBOM
        uses: actions/upload-artifact@v4
        with:
          name: sbom
          path: sbom.cdx.json

Checklist

• All direct and transitive dependencies have identified licenses
• No GPL/AGPL dependencies in proprietary or closed-source code
• No dependencies with missing or UNLICENSED license designation
• License compatibility verified against project license
• LICENSE file present in repository root
• NOTICE file present if using Apache-licensed dependencies
• THIRD-PARTY-LICENSES file generated and current
• SBOM generated for every release
• License allowlist check integrated into CI pipeline
• SBOM generation integrated into CI pipeline
• Transitive dependencies audited (not just direct deps)

When to Escalate

Escalate to legal or human review when any of these apply:

• A critical dependency uses GPL/AGPL and no permissive alternative exists
• A dependency has no license file and the author is unresponsive
• License text is custom, modified, or ambiguous (not a standard SPDX identifier)
• Dual-licensed dependency requires choosing between commercial and open-source terms
• Government, healthcare, or regulated-industry compliance requirements apply
• Conflicting license obligations exist in the dependency tree (e.g., GPL-2.0-only vs Apache-2.0)
• Preparing for acquisition, IPO, or other due-diligence event requiring license audit sign-off