diff --git a/.github/workflows/validate.yml b/.github/workflows/validate.yml
index 252f06e8..253fb8f7 100644
--- a/.github/workflows/validate.yml
+++ b/.github/workflows/validate.yml
@@ -193,6 +193,9 @@ jobs:
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
 
+      - name: Run dependency audit
+        run: pnpm audit --audit-level=critical
+
       - name: Build core package
         run: pnpm --filter @harness-kit/core build
 
diff --git a/SECURITY.md b/SECURITY.md
new file mode 100644
index 00000000..48a72b34
--- /dev/null
+++ b/SECURITY.md
@@ -0,0 +1,225 @@
+# Security Policy
+
+## Reporting Security Issues
+
+**Please do not report security vulnerabilities through public GitHub issues.**
+
+If you discover a security vulnerability in harness-kit, please report it through [GitHub Security Advisories](https://github.com/harnessprotocol/harness-kit/security/advisories/new). Include the following information:
+
+- Description of the vulnerability
+- Steps to reproduce the issue
+- Potential impact
+- Suggested remediation (if any)
+
+**Expected Response Time:** We aim to acknowledge security reports within 48 hours and provide an initial assessment within 5 business days.
+
+### Security Updates
+
+Security updates will be released as patch versions and documented in the [GitHub Security Advisories](https://github.com/harnessprotocol/harness-kit/security/advisories) section.
+
+## Security Model
+
+### Architecture Overview
+
+harness-kit is a plugin marketplace and configuration system for AI coding tools. The project consists of:
+
+1. **Plugins** - Installable skills, agents, and scripts distributed through the marketplace
+2. **Marketplace App** - Next.js web application for browsing and discovering plugins
+3. **Board Server** - WebSocket server for real-time kanban board features
+4. **Desktop App** - Tauri-based desktop application with React frontend and Rust backend
+5. **CLI Tools** - Command-line utilities for harness management
+
+### Trust Boundaries
+
+- **Plugin Code Execution**: Plugins execute with the same permissions as Claude Code. Users should review plugin code before installation.
+- **Web Services**: The marketplace app and board-server expose HTTP/WebSocket endpoints. These services should be deployed with appropriate network isolation.
+- **Desktop App**: The Tauri desktop app has access to local filesystem and system APIs through its Rust backend.
+
+### Authentication & Authorization
+
+- **Supabase Integration**: The marketplace app uses Supabase for authentication and data persistence. Row-level security (RLS) policies control data access.
+- **Board Server**: Currently designed for local development use. Production deployments should implement authentication and authorization appropriate to their threat model.
+- **Plugin Permissions**: Plugins inherit the execution context of Claude Code and have access to the local filesystem within the project directory.
+
+## Secrets Management
+
+### Environment Variables
+
+Sensitive configuration values should NEVER be committed to version control. Use `.env` files for local development and environment-specific secret management for production.
+
+**For Local Development:**
+1. Copy `.env.example` to `.env` in the relevant service directory
+2. Fill in your credentials (never commit the `.env` file)
+3. Ensure `.env` is in `.gitignore`
+
+**Required Secrets by Service:**
+
+**Marketplace (`apps/marketplace/`):**
+- `NEXT_PUBLIC_SUPABASE_URL` - Supabase project URL (public, but project-specific)
+- `NEXT_PUBLIC_SUPABASE_ANON_KEY` - Supabase anonymous key (public, rate-limited)
+- `SUPABASE_SERVICE_ROLE_KEY` - Server-side Supabase key (PRIVATE, keep secret)
+- `SUPABASE_URL` - Supabase URL for seed scripts (PRIVATE)
+- `REGISTER_API_KEY` - API key protecting the /api/register endpoint (PRIVATE, keep secret)
+- `GITHUB_TOKEN` - GitHub personal access token for sync operations (PRIVATE, optional)
+- `GITHUB_WEBHOOK_SECRET` - GitHub webhook secret (PRIVATE, keep secret)
+
+**Board Server (`packages/board-server/`):**
+- `BOARD_PORT` - WebSocket server port (default: 4800)
+
+### Secret Rotation
+
+- **Supabase Keys**: Rotate through Supabase project settings. Update environment variables in all deployment environments.
+- **Database Credentials**: Rotate through your database provider. Update `DATABASE_URL` in all environments.
+- **API Keys**: Any third-party API keys should be rotated according to the provider's recommendations.
+
+### Best Practices
+
+- Use environment-specific secrets management (e.g., GitHub Secrets, Vercel Environment Variables, AWS Secrets Manager)
+- Never log secrets or include them in error messages
+- Use `.env.example` files to document required variables without including real values
+- Limit secret access to the minimum required scope (e.g., use Supabase anon key for client-side, service role key only for server operations)
+
+## Deployment Security
+
+### Production Checklist
+
+Before deploying harness-kit services to production:
+
+- [ ] All secrets are stored in a secure secrets management system (not in code or config files)
+- [ ] `.env` files are excluded from version control (verify `.gitignore`)
+- [ ] CORS is configured to allow only trusted origins
+- [ ] Supabase Row Level Security (RLS) policies are enabled and tested
+- [ ] HTTPS/TLS is enabled for all web services
+- [ ] WebSocket connections use WSS (secure WebSocket)
+- [ ] Database connection strings use SSL/TLS
+- [ ] Rate limiting is configured for public API endpoints
+- [ ] Logging is configured to exclude sensitive data
+- [ ] Security headers are configured (CSP, HSTS, X-Frame-Options, etc.)
+
+### Marketplace App (`apps/marketplace/`)
+
+- Deploy on a platform with built-in DDoS protection (e.g., Vercel, Cloudflare)
+- Configure Content Security Policy (CSP) headers
+- Enable Supabase RLS policies for all tables
+- Use `NEXT_PUBLIC_` prefix only for truly public variables
+- Never expose `SUPABASE_SERVICE_ROLE_KEY` to the client
+
+### Board Server (`packages/board-server/`)
+
+- Run behind a reverse proxy (nginx, Caddy) with TLS termination
+- Implement authentication before production use
+- Configure CORS to whitelist specific origins only
+- Set reasonable rate limits on WebSocket connections
+- Monitor for abnormal connection patterns
+
+### Desktop App (`apps/desktop/`)
+
+- Code-sign the application for distribution
+- Keep Tauri and dependencies up to date
+- Follow Tauri security best practices: https://tauri.app/v1/guides/security/
+- Validate all IPC commands from the frontend
+- Limit filesystem access to necessary directories
+
+## Dependency Management
+
+### Automated Scanning
+
+We use automated dependency scanning to detect known vulnerabilities:
+
+- **Node.js Dependencies**: `pnpm audit` runs in CI for all JavaScript/TypeScript packages
+- **Rust Dependencies**: `cargo audit` can be used for the Tauri desktop app (`apps/desktop/src-tauri/`)
+- **GitHub Dependabot**: Automatically creates PRs for dependency updates with known security issues
+
+### Audit Thresholds
+
+Our CI pipeline uses the following severity thresholds:
+
+- **Critical**: Immediate action required
+- **High**: Address within 7 days
+- **Moderate**: Address within 30 days
+- **Low**: Address in next planned update
+
+### Dependency Updates
+
+We follow these practices for dependency management:
+
+1. **Regular Updates**: Review and update dependencies monthly
+2. **Security Patches**: Apply security patches as soon as possible
+3. **Lock Files**: Commit lock files (`pnpm-lock.yaml`, `Cargo.lock`) to ensure reproducible builds
+4. **Minimal Dependencies**: Avoid unnecessary dependencies to reduce attack surface
+5. **Trusted Sources**: Only use dependencies from trusted registries (npm, crates.io)
+
+### Running Security Audits Locally
+
+**Node.js/TypeScript Projects:**
+```bash
+# Run audit for all workspace packages
+pnpm audit
+
+# Run audit with specific severity threshold
+pnpm audit --audit-level=moderate
+
+# Get detailed JSON output
+pnpm audit --json
+```
+
+**Rust Projects:**
+```bash
+# Install cargo-audit
+cargo install cargo-audit
+
+# Run audit on desktop app
+cd apps/desktop/src-tauri
+cargo audit
+```
+
+### Vulnerability Response
+
+When a vulnerability is discovered:
+
+1. **Assess Impact**: Determine if the vulnerability affects harness-kit's usage of the dependency
+2. **Check for Updates**: Look for a patched version of the dependency
+3. **Update or Mitigate**: Update to a safe version or implement mitigations if no update is available
+4. **Test**: Verify the update doesn't break functionality
+5. **Document**: Update changelog and notify users if the vulnerability could affect deployments
+
+### Plugin Security
+
+Since harness-kit is a plugin marketplace, special attention is given to plugin dependencies:
+
+- Plugin authors should follow the same security practices
+- Users should review plugin code and dependencies before installation
+- Plugins with known vulnerabilities will be flagged in the marketplace
+- Plugin updates should be tested before installation
+
+## Supported Versions
+
+We provide security updates for the following versions:
+
+| Version | Supported          |
+| ------- | ------------------ |
+| main    | :white_check_mark: |
+| 0.x.x   | :white_check_mark: |
+
+We recommend always using the latest stable release.
+
+## Security Tooling
+
+In addition to dependency scanning, we recommend:
+
+- **Static Analysis**: Use TypeScript strict mode and Rust's clippy for code quality
+- **Git Hooks**: Use pre-commit hooks to prevent committing secrets (e.g., detect-secrets, git-secrets)
+- **Code Review**: All changes should be reviewed before merging
+- **Principle of Least Privilege**: Grant minimal necessary permissions to services and users
+
+## Additional Resources
+
+- [OWASP Top 10](https://owasp.org/www-project-top-ten/)
+- [Tauri Security Guide](https://tauri.app/v1/guides/security/)
+- [Next.js Security Headers](https://nextjs.org/docs/advanced-features/security-headers)
+- [Supabase Security](https://supabase.com/docs/guides/auth/security)
+- [npm Security Best Practices](https://docs.npmjs.com/security-best-practices)
+
+---
+
+**Last Updated:** 2026-03-28
diff --git a/apps/marketplace/.env.example b/apps/marketplace/.env.example
new file mode 100644
index 00000000..9241f4f5
--- /dev/null
+++ b/apps/marketplace/.env.example
@@ -0,0 +1,20 @@
+# Supabase project URL (from Project Settings → API)
+NEXT_PUBLIC_SUPABASE_URL=https://<project-ref>.supabase.co
+
+# Supabase anon key — safe to expose in the browser
+NEXT_PUBLIC_SUPABASE_ANON_KEY=<anon-key>
+
+# Supabase service role key — server-only, never expose publicly
+SUPABASE_SERVICE_ROLE_KEY=<service-role-key>
+
+# Supabase URL (non-public) — used in seed scripts and server-side operations
+SUPABASE_URL=https://<project-ref>.supabase.co
+
+# API key for plugin registration — protects the /api/register endpoint
+REGISTER_API_KEY=<api-key>
+
+# GitHub personal access token — used by the sync route to read private repo contents (optional)
+GITHUB_TOKEN=<github-pat>
+
+# GitHub webhook secret — must match the secret set in the GitHub webhook config
+GITHUB_WEBHOOK_SECRET=<webhook-secret>
diff --git a/apps/marketplace/SETUP.md b/apps/marketplace/SETUP.md
index caedb0b6..b0893928 100644
--- a/apps/marketplace/SETUP.md
+++ b/apps/marketplace/SETUP.md
@@ -2,26 +2,23 @@
 
 ## Environment variables
 
-Create `apps/marketplace/.env.local` with the following values:
+Copy `.env.example` to `.env.local` and fill in your values:
 
-```
-# Supabase project URL (from Project Settings → API)
-NEXT_PUBLIC_SUPABASE_URL=https://<project-ref>.supabase.co
-
-# Supabase anon key — safe to expose in the browser
-NEXT_PUBLIC_SUPABASE_ANON_KEY=<anon-key>
-
-# Supabase service role key — server-only, never expose publicly
-SUPABASE_SERVICE_ROLE_KEY=<service-role-key>
-
-# GitHub personal access token — used by the sync route to read private repo contents (optional)
-GITHUB_TOKEN=<github-pat>
-
-# GitHub webhook secret — must match the secret set in the GitHub webhook config
-GITHUB_WEBHOOK_SECRET=<webhook-secret>
+```bash
+cp apps/marketplace/.env.example apps/marketplace/.env.local
 ```
 
-Supabase values are in your project dashboard under **Settings → API**. GitHub values come from your repo webhook config and a GitHub PAT.
+Required variables:
+
+| Variable | Where to get it |
+|----------|----------------|
+| `NEXT_PUBLIC_SUPABASE_URL` | Supabase project dashboard → Settings → API |
+| `NEXT_PUBLIC_SUPABASE_ANON_KEY` | Supabase project dashboard → Settings → API |
+| `SUPABASE_SERVICE_ROLE_KEY` | Supabase project dashboard → Settings → API (server-only, never expose publicly) |
+| `SUPABASE_URL` | Same as `NEXT_PUBLIC_SUPABASE_URL` — used in seed scripts and server-side operations |
+| `REGISTER_API_KEY` | Choose any secret string — protects the `/api/register` endpoint |
+| `GITHUB_TOKEN` | GitHub PAT with repo read access (optional — for syncing private repo content) |
+| `GITHUB_WEBHOOK_SECRET` | Match the secret set in your GitHub webhook config |
 
 ## Seed the database
 
diff --git a/packages/board-server/.env.example b/packages/board-server/.env.example
new file mode 100644
index 00000000..398fd2c6
--- /dev/null
+++ b/packages/board-server/.env.example
@@ -0,0 +1,5 @@
+# Board Server Configuration
+
+# WebSocket server port
+# Default: 4800
+BOARD_PORT=4800