AI Agentic Development | Next.js Supabase Turbo

AI Agentic Development uses AI coding assistants like Claude Code, Google Antigravity or Cursor to write code within your project. MakerKit ships with instruction files (AGENTS.md, CLAUDE.md) that teach these AI agents your codebase patterns, available skills, and project conventions so they generate code matching your architecture.

The kit includes pre-configured agent rules for Claude Code, Google Antigravity, Cursor, Windsurf, Codex, and Gemini. In our extensive testing with state-of-the-art agents like Claude Code, we found that modern tools already crawl existing patterns and learn from your codebase. With a polished codebase like MakerKit, agents have the context they need to produce good code without exhaustive API documentation.

Agent Configuration Files

MakerKit uses a hierarchical system of instruction files. Global rules live at the project root, and package-specific rules live in subdirectories.

File Locations

Hierarchical Structure

AI agents read instructions from multiple files based on context. When you work in apps/web, the agent reads:

1. Root AGENTS.md (global patterns, commands, tech stack)
2. apps/web/AGENTS.md (route organization, component patterns)
3. apps/web/supabase/AGENTS.md (database migrations, RLS policies)

This hierarchy means agents get more specific instructions as they work deeper in the codebase.

AGENTS.md                          # Global: tech stack, commands, patterns
├── apps/web/AGENTS.md             # App: routes, components, config files
│   ├── apps/web/supabase/AGENTS.md    # Database: schemas, migrations, RLS
│   └── apps/web/app/admin/AGENTS.md   # Admin: super admin features
├── packages/ui/AGENTS.md          # UI: components, design system
├── packages/supabase/AGENTS.md    # Supabase: clients, auth, types
├── packages/features/AGENTS.md    # Features: feature packages
└── packages/next/AGENTS.md        # Next.js: actions, routes, utilities

What Agents Learn

The root AGENTS.md teaches agents:

• Tech stack: Next.js 16, React 19, Supabase, Tailwind CSS 4, Turborepo
• Multi-tenant architecture: Personal accounts vs team accounts, account_id foreign keys
• Essential commands: pnpm dev, pnpm typecheck, pnpm supabase:web:reset
• Key patterns: Server Actions with authActionClient, Route Handlers with enhanceRouteHandler
• Authorization: RLS enforces access control, admin client bypasses RLS

Package-specific files add context for that area:

# packages/supabase/AGENTS.md
## Client Usage
### Server Components (Preferred)
import { getSupabaseServerClient } from '@kit/supabase/server-client';
const client = getSupabaseServerClient();
// RLS automatically enforced
### Admin Client (Use Sparingly)
import { getSupabaseServerAdminClient } from '@kit/supabase/server-admin-client';
// CRITICAL: Bypasses RLS - validate manually!

Editor Configuration

Claude Code

Claude Code reads CLAUDE.md files automatically. The root file references @AGENTS.md to include those instructions.

No configuration needed. Start Claude Code in your project directory:

claude

Claude Code discovers and reads the instruction files on startup.

Google Antigravity

Antigravity reads the root AGENTS.md automatically at session start, in both the desktop app and the agy CLI. It also reads .gemini/GEMINI.md, which takes precedence when the two conflict — the kit's GEMINI.md simply points the agent at the AGENTS.md files, so the two work together.

Nested AGENTS.md files are opt-in. To get the package-level instructions (routes, database, UI, feature packages), enable them once:

Settings → Agent → Load nested AGENTS.md files

This matters on MakerKit: most of the useful context lives in the 13 package-level files rather than the root one.

Antigravity natively recognises the .agents/ directory, so the kit's skills, custom agent and MCP configuration work without conversion:

.agents/
├── skills/               # Discovered and activated automatically
├── agents/               # Custom agents (agy --agent <name>)
└── mcp_config.json       # MCP servers for this project

Antigravity activates skills on its own using progressive disclosure: it reads the name and description of each skill and loads the full instructions only when your task matches. Run /skills in the CLI to see which ones are available.

Cursor

Cursor reads AGENTS.md files automatically when you open a project. The agent instructions appear in context when you use Cursor's AI features.

For the best experience:

1. Open the project root in Cursor (not a subdirectory)
2. The agent rules load automatically
3. Use Cmd+K or the chat panel to interact with the agent

Windsurf

Windsurf uses the same AGENTS.md files as Cursor. Open your project and the rules apply automatically.

Codex

Codex reads AGENTS.md files. Open the project root and the agent instructions apply to generated code.

Gemini

Gemini reads from .gemini/GEMINI.md. This file points to the AGENTS.md files:

# .gemini/GEMINI.md
- Check for the presence of AGENTS.md files in the project workspace
- There may be additional AGENTS.md in sub-folders with additional specific instructions

MCP Server (Optional)

The Makerkit MCP Server gives AI agents additional tools for working with the codebase. See the MCP Server documentation for setup instructions.

MCP tools help agents:

• Understand the project structure
• Navigate between related files
• Apply MakerKit-specific patterns

Customizing Rules

The default rules cover MakerKit patterns. Add your own rules for application-specific logic.

Adding Business Logic Rules

Create or edit AGENTS.md files to include your domain knowledge:

# apps/web/AGENTS.md (add to existing file)
## Business Logic
### Subscription Tiers
- Free: 1 team member, 3 projects
- Pro: 10 team members, unlimited projects
- Enterprise: Unlimited everything, SSO
### Project Limits
Check limits before creating projects:
- Use `checkProjectLimit(accountId)` from `~/lib/server/projects`
- Returns { allowed: boolean, current: number, limit: number }
### Naming Conventions
- Projects use kebab-case slugs: "my-project-name"
- Team accounts use slugs, not IDs, in URLs

What Makes Effective Agent Rules

In our testing, we noticed that adding detailed API instructions to agent rules has diminishing returns. Modern agents like Claude Code crawl your existing code, learn the patterns, and apply them. What actually moves the needle:

1. Must-do rules: Things the agent should always do
2. Must-not-do rules: Things the agent should never do
3. Router instructions: Where to find things the agent needs

# apps/web/AGENTS.md (add to existing file)
## MUST DO
- Always use `authActionClient` for Server Actions
- Always enable RLS on new tables
- Always run `pnpm typecheck` after changes
- Always use the `Trans` component for user-facing text
## MUST NOT DO
- Never use the admin client without manual auth validation
- Never commit .env files or secrets
- Never use `any` type in TypeScript
- Never skip RLS policies on tables with user data
## Where to Find Things
- Auth patterns: `packages/supabase/src/clients/`
- UI components: `packages/ui/src/`
- Billing logic: `packages/billing/`
- Database schemas: `apps/web/supabase/schemas/`

This approach works better than documenting every API because agents learn APIs from code, but they need explicit guidance on project-specific constraints and conventions.

Adding Feature Flags

Document which features are gated so agents know what's available:

## Feature Flags
Check `config/feature-flags.config.ts` for current flags:
- `enableTeamAccounts`: Team workspaces enabled
- `enableTeamCreation`: Users can create new teams
- `enableTeamAccountBilling`: Team billing enabled
- `enablePersonalAccountBilling`: Personal account billing enabled
- `enableNotifications`: In-app notifications enabled
Import the config directly:
import featureFlags from '~/config/feature-flags.config';
if (featureFlags.enableTeamCreation) { /* ... */ }

Agent Directory Structure

The kit ships the same skills twice, in the two locations agent tools look for them.

Claude Code uses the .claude/ directory:

.claude/
├── agents/               # Custom agent definitions
│   └── code-quality-reviewer.md
├── skills/               # Reusable skills
│   ├── bug-hunt/
│   ├── bug-hunt-lite/
│   ├── playwright-e2e/
│   ├── postgres-expert/
│   ├── react-form-builder/
│   ├── reviewer/
│   ├── rls-review/
│   ├── server-action-builder/
│   └── service-builder/
└── settings.local.json   # Local permissions (git-ignored)

Antigravity uses the .agents/ directory, which holds the same skills plus its MCP configuration:

.agents/
├── agents/               # Custom agents
│   └── code-quality-reviewer.md
├── skills/               # Same skills as .claude/skills
└── mcp_config.json       # MCP servers for this project

If you edit a skill, update both copies so the behaviour stays identical across tools.

Built-in Skills

The kit includes skills that provide specialized guidance for common tasks. They work in Claude Code (from .claude/skills) and in Antigravity (from .agents/skills).

If you touch RLS, the database schema, or anything under apps/web/supabase/, run /rls-review before merging. It writes cross-tenant attacks as PgTAP tests and runs them, rather than reading the policies and declaring them safe.

Using Skills

Invoke a skill by typing its command at the start of your message:

/postgres-supabase-expert Create a projects table with RLS policies for team access

/server-action-builder Create an action to update user settings

Custom Agents

The kit ships one custom agent, code-quality-reviewer, which reviews recent changes against the standards in the AGENTS.md files.

Claude Code loads it from .claude/agents/. Antigravity loads it from .agents/agents/ and can also run it as the main agent:

agy --agent code-quality-reviewer

Add your own by dropping a markdown file with name and description frontmatter into the same directories.

Adding External Skills

The Agent Skills project provides additional skills you can install:

npx add-skill vercel-labs/agent-skills

Available skills:

• react-best-practices: Performance optimization guidelines from Vercel Engineering (40+ rules across 8 categories)
• web-design-guidelines: UI audit with accessibility checks (100+ rules covering accessibility, performance, UX)
• vercel-deploy-claimable: Deploy directly from conversations with live preview URLs

Verification Workflow

Agents are instructed to run verification after making changes:

pnpm typecheck        # Must pass
pnpm lint:fix         # Auto-fix issues
pnpm format:fix       # Format code

If an agent skips verification, remind it:

Run typecheck and lint:fix to verify the changes

Common Patterns Agents Know

Server Actions

Agents use authActionClient for Server Actions:

'use server';
import { authActionClient } from '@kit/next/safe-action';
import * as z from 'zod';
const schema = z.object({
  name: z.string().min(1),
});
export const createProjectAction = authActionClient
  .inputSchema(schema)
  .action(async ({ parsedInput: data, ctx: { user } }) => {
    // Implementation
  });

Route Handlers

Agents use enhanceRouteHandler for API routes:

import { enhanceRouteHandler } from '@kit/next/routes';
export const POST = enhanceRouteHandler(
  async ({ body, user }) => {
    // Implementation
    return NextResponse.json({ success: true });
  },
  { schema: requestSchema }
);

Database Queries

Agents prefer Server Components with the standard client:

import { getSupabaseServerClient } from '@kit/supabase/server-client';
async function ProjectList() {
  const client = getSupabaseServerClient();
  const { data } = await client.from('projects').select('*');
  // RLS enforced automatically
}

Best Practices for Using AI Agents

After extensive use of AI agents with MakerKit, we've identified what works:

Keep AGENTS.md Files Focused

Long instruction files cause context drift where agents forget earlier rules. Keep each file under 500 lines. Split by concern rather than cramming everything into the root file.

Use Rules as a Router

Rather than documenting every API, tell agents where to find things:

## Where to Look
- Need a UI component? Check `packages/ui/src/` first
- Building a form? See `packages/ui/src/shadcn/form.tsx` for patterns
- Adding a Server Action? Reference `apps/web/app/home/_lib/server/`

Agents are excellent at reading code once they know where to look.

Explicit Constraints Beat Implicit Conventions

"Always use authActionClient" works better than "We prefer using authActionClient for most cases." Agents follow explicit rules; they guess at preferences.

Let Agents Learn from Your Codebase

With a consistent codebase like MakerKit, agents pick up patterns automatically. You don't need to document that Server Components fetch data or that forms use Zod. Focus your rules on project-specific decisions and gotchas.

Troubleshooting

Agent Ignores Rules

1. Verify files exist at the expected locations
2. Check file names match exactly (case-sensitive)
3. Restart your editor to reload configuration

Antigravity Ignores the Package-Level Rules

Antigravity reads the root AGENTS.md by default, but nested files are opt-in. Enable Settings → Agent → Load nested AGENTS.md files, then start a new session.

Antigravity Does Not See the MCP Server

1. Build it first: pnpm --filter "@kit/mcp-server" build
2. Confirm packages/mcp-server/build/index.cjs exists
3. Run /mcp in the CLI, or open the MCP panel in the IDE, to see the connection status
4. If the project config is not picked up, add the server globally in ~/.gemini/config/mcp_config.json using the absolute path to index.cjs

Antigravity Does Not List the Skills

Skills must live in .agents/skills/<skill-name>/SKILL.md with name and description frontmatter. Antigravity uses the description to decide when to activate a skill, so a missing description means the skill is never selected. Run /skills in the CLI to see what was discovered.

Agent Generates Wrong Patterns

Add explicit examples to your AGENTS.md:

## Patterns
### CORRECT - Use authActionClient
export const action = authActionClient.inputSchema(schema).action(async ({ parsedInput: data, ctx: { user } }) => {});
### INCORRECT - Raw Server Action
export async function action(data: FormData) {} // Missing validation

Agent Misunderstands Structure

Add a quick reference section:

## Quick Reference
- App routes: `apps/web/app/`
- Shared components: `packages/ui/src/`
- Database schemas: `apps/web/supabase/schemas/`
- Feature packages: `packages/features/*/`

Next Steps

• Configure the MCP Server for enhanced agent capabilities
• Add LLM rules for additional context from documentation
• Review conventions to understand the patterns agents follow