Chapter 12

Extensions

Install, create, and publish guardrail extensions.

What Extensions Add

Extensions are packaged bundles of instruction files, agents, and prompts that add domain-specific guardrails to your project. They give you drop-in expertise for domains you haven't solved yet: instead of writing compliance rules from scratch, install a community extension and get pre-built knowledge.

Browsing the Catalog

Terminal

# Browse all extensions
pforge ext search

# Filter by keyword
pforge ext search compliance

# Get details about a specific extension
pforge ext info saas-multi-tenancy

The catalog is also browsable in the Dashboard Extensions tab.

Featured Extensions

Extension	Category	What It Adds
`saas-multi-tenancy`	Architecture	Tenant isolation patterns, RLS enforcement, cache separation, cross-tenant audit
`azure-infrastructure`	Cloud	Bicep/Terraform guardrails, resource naming, tagging, cost governance
`plan-forge-memory`	Integration	OpenBrain memory, persistent context across sessions, postmortem injection

Installing an Extension

Terminal

# One-step install from catalog
pforge ext add saas-multi-tenancy

# Install from local path
pforge ext install .forge/extensions/my-extension

This copies instruction files to .github/instructions/, agents to .github/agents/, and prompts to .github/prompts/. The extension metadata is tracked in .forge/extensions/.

Creating Your Own Extension

Create directory: .forge/extensions/my-extension/

Add extension.json manifest:

extension.json

{
  "name": "my-extension",
  "version": "1.0.0",
  "description": "Domain-specific guardrails for healthcare",
  "author": "your-name",
  "category": "compliance"
}

Add guardrail files:

Extension structure

my-extension/
├── extension.json
├── instructions/
│   ├── hipaa-compliance.instructions.md
│   └── phi-handling.instructions.md
├── agents/
│   └── hipaa-reviewer.agent.md
└── prompts/
    └── compliance-audit.prompt.md

Test locally: pforge ext install .forge/extensions/my-extension
Publish: pforge ext publish .forge/extensions/my-extension

Publishing

Publishing generates a catalog entry, it doesn't upload anything. You submit via pull request:

Run pforge ext publish .forge/extensions/my-extension
Fork plan-forge on GitHub
Add the generated entry to extensions/catalog.json
Open a PR with title: feat(catalog): add my-extension

Spec Kit compatible: pforge ext publish outputs both a Plan Forge catalog entry and a Spec Kit-compatible extensions.json entry in one command.

Managing Extensions

Terminal

# List installed extensions
pforge ext list

# Remove an extension
pforge ext remove healthcare-compliance

📄 Full reference: Extensions guide, PUBLISHING.md on GitHub