---
title: Transforms
description: Modify requests and responses with system prompts, RAG injection, anonymization, and normalization.
---

Transforms modify requests before they reach the provider (input transforms) or responses before they reach the client (output transforms).

## Transform Interface

```go
type Transform interface {
    Name() string
    Phase() Phase   // Input or Output
    Apply(ctx context.Context, data *TransformData) error
}
```

## Built-in Transforms

### System Prompt Injection

Prepend a system prompt to every request:

```go
import "github.com/xraph/nexus/transform"

registry := transform.NewRegistry()
registry.Register(transform.NewSystemPrompt(
    "You are a helpful assistant for Acme Corp.",
))

nexus.WithTransforms(registry)
```

### RAG Context Injection

Inject retrieval-augmented generation context:

```go
registry.Register(transform.NewRAG(ragRetriever))
```

### Data Anonymization

Strip sensitive data before sending to the provider:

```go
registry.Register(transform.NewAnonymizer())
```

### Output Normalization

Normalize response format across providers:

```go
registry.Register(transform.NewNormalizer())
```

## Per-Tenant Transforms

Combine transforms with tenant context for per-customer system prompts:

```go
registry.Register(transform.NewSystemPrompt(
    "You are a support agent for {{tenant}}.",
    transform.WithTenantAware(true),
))
```