Invoice MCP Server

A Next.js web app deployed on Vercel that acts as an MCP (Model Context Protocol) server for inventory management. Demonstrates all Auth0 for MCP capabilities via the @auth0/ai-vercel SDK.

Auth0 for MCP Capabilities

Related MCP server: mcp_auth_server

MCP Endpoint

POST/GET/DELETE https://<your-app>.vercel.app/api/mcp

All requests require:

Authorization: Bearer <Auth0 access_token>

The access token must have the read:inventory scope (plus write:inventory for mutations).

Tools

listInventory

Returns all inventory items. No extra authorization beyond the bearer token.

addItem

{ "name": "Widget X", "quantity": 50, "price": 12.99 }

Requires FGA relation: user:<sub> writer inventory:default

deleteItem

{ "id": "item-001" }

Requires:

1. FGA relation: user:<sub> owner inventory:item-001

2. CIBA approval — the user receives a push notification and must approve

commentItem

{ "id": "item-001", "comment": "Reorder ASAP" }

Saves the comment and posts a Slack message via Auth0 Token Vault (user must have linked Slack account).

Setup

1. Auth0 Tenant

1. Create an API in Auth0 with audience matching AUTH0_AUDIENCE, with scopes read:inventory and write:inventory.

2. Create an M2M application with Client Credentials grant for CIBA token exchange and Token Vault operations. Note the Client ID and Secret.

3. Enable Auth0 Fine Grained Authorization and create a store. Configure tuples for your test users:

   user:<sub> writer inventory:default
   user:<sub> owner inventory:item-001

4. Enable CIBA on your tenant (requires a push notification provider).

5. Configure a Slack social connection in Auth0 with chat:write scope and enable Token Vault storage.

2. Environment Variables

Copy .env.example to .env.local and fill in your values:

cp .env.example .env.local

Add the same variables in your Vercel project settings (Settings → Environment Variables).

Optional variable for Slack notifications:

SLACK_CHANNEL_ID=C0123456789
SLACK_REFRESH_TOKEN=xoxe-...   # fallback for testing; normally read from JWT claims

3. Deploy to Vercel

npm install
vercel deploy

Or connect your GitHub repo to Vercel for automatic deployments.

4. Connect an MCP Client

{
  "mcpServers": {
    "inventory": {
      "url": "https://<your-app>.vercel.app/api/mcp",
      "headers": {
        "Authorization": "Bearer <access_token>"
      }
    }
  }
}

Get an access token via the Auth0 Device Flow, Authorization Code flow, or your preferred grant.

FGA Model

Minimum required tuples for testing:

type user
type inventory
  relations
    define writer: [user]
    define owner: [user]

Create tuples:

fga tuple write --store-id $FGA_STORE_ID \
  --user user:<your-sub> \
  --relation writer \
  --object inventory:default

fga tuple write --store-id $FGA_STORE_ID \
  --user user:<your-sub> \
  --relation owner \
  --object inventory:item-001

Known Limitations

• CIBA store: The in-memory MemoryStore (default in Auth0AI) does not persist across Vercel cold starts. For production, configure a persistent store such as @auth0/ai-redis backed by Vercel KV or Upstash Redis.

• Inventory store: In-memory; resets on cold start. Replace with Vercel Postgres, Neon, or similar for persistence.

Local Development

npm install
cp .env.example .env.local
# fill in .env.local
npm run dev

MCP server will be available at http://localhost:3000/api/mcp.