Next.js + tRPC Setup

This guide walks you through configuring Massu AI for a Next.js project that uses tRPC for API routing and Prisma for database access. This is the configuration that enables the most Massu AI features.

Prerequisites

Next.js 13+ with App Router
tRPC v10 or v11
Prisma ORM
Massu AI installed (Installation Guide)

Step 1: Configuration

Create massu.config.yaml in your project root:

yaml

project:
  name: my-nextjs-app
  root: auto

framework:
  type: typescript
  router: trpc
  orm: prisma
  ui: nextjs

paths:
  source: src
  aliases:
    "@": src
    "@/components": src/components
    "@/lib": src/lib
  middleware: src/middleware.ts

toolPrefix: massu

domains:
  - name: orders
    routers:
      - "src/server/routers/orders*"
    pages:
      - "src/app/orders/**"
      - "src/app/(dashboard)/orders/**"
    components:
      - "src/components/orders/**"
    allowedImportsFrom:
      - shared
      - auth

  - name: auth
    routers:
      - "src/server/routers/auth*"
    pages:
      - "src/app/auth/**"
      - "src/app/login/**"
    components:
      - "src/components/auth/**"
    allowedImportsFrom:
      - shared

  - name: shared
    routers: []
    pages: []
    components:
      - "src/components/ui/**"
      - "src/lib/**"
    allowedImportsFrom: []

rules:
  - pattern: "src/server/**/*.ts"
    severity: CRITICAL
    rules:
      - "All mutations must use protectedProcedure"
      - "Never expose raw error details to clients"
      - "Validate all inputs with Zod schemas"

  - pattern: "src/app/**/page.tsx"
    severity: HIGH
    rules:
      - "Pages must be server components by default"
      - "Use Suspense boundaries for dynamic content"

  - pattern: "src/middleware.ts"
    severity: CRITICAL
    rules:
      - "No Node.js dependencies (Edge Runtime only)"
      - "Keep middleware lightweight"

security:
  auto_score_on_edit: true
  score_threshold_alert: 40

analytics:
  cost:
    models:
      claude-opus-4-6:
        input_per_million: 15
        output_per_million: 75
        cache_read_per_million: 1.5
        cache_write_per_million: 3.75
    currency: USD

Step 2: Initial Sync

Start Claude Code and run the initial sync:

> Run massu_sync to index the codebase

With tRPC configured, you should see tRPC procedure mapping in the output:

Indexes rebuilt:
Import edges: 342
tRPC procedures: 84 (62 with UI, 22 without)
Page deps: 31 pages
Middleware tree: 12 files

Step 3: Verify tRPC Mapping

Check that tRPC mapping is working:

> Run massu_trpc_map with uncoupled: true

This shows procedures without UI callers -- potential dead code in your API layer.

Step 4: Verify Domain Boundaries

> Run massu_domains with crossings: true

This shows cross-domain import violations based on your domain configuration.

Step 5: Check Middleware Tree

> Run massu_context for src/middleware.ts

Verify the middleware tree analysis is working. Any file in the middleware import chain will get Edge Runtime warnings.

Tips for Next.js Projects

Set paths.middleware to enable middleware tree analysis and Edge Runtime warnings
Configure domains to match your Next.js route groups
The massu_schema tool works with Prisma to catch column name mismatches
Use massu_coupling_check to find tRPC procedures that no UI component calls
The post-edit-context hook will warn about Edge Runtime restrictions when editing middleware-tree files