# contract infer (/docs/cli/contract-infer)

Infer a starter contract from an existing database.

Location: CLI > contract infer

`contract infer` inspects a live database and writes a starter PSL contract. An existing file at the output path is overwritten, with a warning.

Use it when you are adding Prisma ORM to an existing database and want an initial contract to review and edit.

## Usage

#### bun

```bash
bunx prisma contract infer [--db "$DATABASE_URL"]
```

#### pnpm

```bash
pnpm prisma contract infer [--db "$DATABASE_URL"]
```

#### yarn

```bash
yarn prisma contract infer [--db "$DATABASE_URL"]
```

#### npm

```bash
npx prisma contract infer [--db "$DATABASE_URL"]
```

## Options

| Option            | What it does                                                                                                                                 |
| ----------------- | -------------------------------------------------------------------------------------------------------------------------------------------- |
| `--db <url>`      | Connects to the database. Optional: without it the command uses `db.connection` from `prisma.config.ts`, and fails only when neither is set. |
| `--output <path>` | Writes the inferred PSL contract to a specific path.                                                                                         |
| `--config <path>` | Read this config file instead of `./prisma.config.ts`.                                                                                       |
| `--json`          | Prints a machine-readable result.                                                                                                            |

## Examples

#### bun

```bash
bunx prisma contract infer --db "$DATABASE_URL"
bunx prisma contract infer --db "$DATABASE_URL" --output ./prisma/contract.prisma
bunx prisma contract infer --db "$DATABASE_URL" --json
```

#### pnpm

```bash
pnpm prisma contract infer --db "$DATABASE_URL"
pnpm prisma contract infer --db "$DATABASE_URL" --output ./prisma/contract.prisma
pnpm prisma contract infer --db "$DATABASE_URL" --json
```

#### yarn

```bash
yarn prisma contract infer --db "$DATABASE_URL"
yarn prisma contract infer --db "$DATABASE_URL" --output ./prisma/contract.prisma
yarn prisma contract infer --db "$DATABASE_URL" --json
```

#### npm

```bash
npx prisma contract infer --db "$DATABASE_URL"
npx prisma contract infer --db "$DATABASE_URL" --output ./prisma/contract.prisma
npx prisma contract infer --db "$DATABASE_URL" --json
```

## What to review

Inference gives you a starting point, not a finished design. Review:

- model and field names
- relation names
- mapped database names
- defaults, indexes, and constraints
- extension-backed column types

The file starts with `// use prisma-8`, because `contract emit` reads only `.prisma` files that start with that line. Each model is named after its table, and gets `@@map` only when the table name differs from the model name: a table `User` becomes `model User`, and a table `user_profile` becomes `model UserProfile` with `@@map("user_profile")`.

Every column default is written in a form `contract emit` accepts, so you can emit the file without editing it. [Default values](/guides/contract-authoring-psl-syntax#default-values) shows those forms. A list column that allows `NULL` is written `Type[]?`, and a list column that is `NOT NULL` is written `Type[]`.

If you keep an inferred contract in version control, running `contract infer` again after an upgrade can write the same database differently, so review the diff before you commit it.

The command stops at `contract.prisma`. Follow it with the emit and sign steps:

#### bun

```bash
bunx prisma contract emit
bunx prisma db sign --db "$DATABASE_URL"
bunx prisma db verify --db "$DATABASE_URL"
```

#### pnpm

```bash
pnpm prisma contract emit
pnpm prisma db sign --db "$DATABASE_URL"
pnpm prisma db verify --db "$DATABASE_URL"
```

#### yarn

```bash
yarn prisma contract emit
yarn prisma db sign --db "$DATABASE_URL"
yarn prisma db verify --db "$DATABASE_URL"
```

#### npm

```bash
npx prisma contract emit
npx prisma db sign --db "$DATABASE_URL"
npx prisma db verify --db "$DATABASE_URL"
```

`db sign` is the handoff point where you record that the existing database matches the reviewed contract.

## Related pages

- [`auth`](/guides/platform-auth): Sign in to your Prisma account from the CLI, sign out, and manage workspace sessions.
- [`branch`](/guides/platform-branch): List platform branches for a project.
- [`bucket`](/guides/platform-bucket): Create and manage object-store buckets.
- [`Configuration`](/guides/introduction-6-configuration): Configure Prisma ORM CLI commands with prisma.config.ts and global flags.
- [`contract emit`](/guides/orm-contract-emit): Emit Prisma ORM contract artifacts.

## Related pages

- [Authentication & Tools](./authentication-tools-index.md)
- [Build](./build-index.md)
- [Changelog](../changelog.md)
- [Concepts](./concepts-index.md)
- [Console commands](./console-commands-index.md)
- [Contract Authoring](./contract-authoring-index.md)
- [Core Concepts](./core-concepts-index.md)
- [Data Modeling](./data-modeling-index.md)
- [Database](./database-index.md)
- [DB commands](./db-commands-index.md)

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