> ## Documentation Index
> Fetch the complete documentation index at: https://docs.semantictest.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Blocks Overview

> All available building blocks for your test pipelines

## What are Blocks?

Blocks are the building pieces of test pipelines. Each block does one thing well and can be combined with other blocks to create complex test scenarios.

## Available Blocks

<CardGroup cols={2}>
  <Card title="HttpRequest" icon="globe" href="/blocks/http-request">
    Make HTTP requests to APIs with full control over method, headers, and body
  </Card>

  <Card title="JsonParser" icon="code" href="/blocks/json-parser">
    Parse JSON strings into structured data
  </Card>

  <Card title="StreamParser" icon="wave-pulse" href="/blocks/stream-parser">
    Parse streaming SSE responses from OpenAI, Vercel AI SDK, and custom formats
  </Card>

  <Card title="ValidateContent" icon="check" href="/blocks/validate-content">
    Validate text content with contains, regex, length checks, and more
  </Card>

  <Card title="ValidateTools" icon="wrench" href="/blocks/validate-tools">
    Validate AI tool calls, order, arguments, and constraints
  </Card>

  <Card title="LLMJudge" icon="gavel" href="/blocks/llm-judge">
    Use AI to evaluate responses semantically with configurable criteria
  </Card>

  <Card title="Loop" icon="rotate" href="/blocks/loop">
    Loop back to previous blocks with max iteration control
  </Card>

  <Card title="MockData" icon="box" href="/blocks/mock-data">
    Return mock data for testing without external dependencies
  </Card>
</CardGroup>

## Block Categories

### HTTP & Data Fetching

* **HttpRequest**: Make API calls
* **MockData**: Test without external dependencies

### Parsing & Transformation

* **JsonParser**: Parse JSON responses
* **StreamParser**: Handle streaming data

### Validation

* **ValidateContent**: Text and content validation
* **ValidateTools**: AI tool call validation
* **LLMJudge**: Semantic validation with AI

### Control Flow

* **Loop**: Retry logic and iterations

## Common Patterns

### API Testing

```json theme={null}
{
  "pipeline": [
    { "block": "HttpRequest" },   // Call API
    { "block": "JsonParser" },    // Parse response
    { "block": "ValidateContent" } // Validate content
  ]
}
```

### AI Agent Testing

```json theme={null}
{
  "pipeline": [
    { "block": "HttpRequest" },    // Call AI API
    { "block": "StreamParser" },   // Parse streaming response
    { "block": "ValidateTools" },  // Check tool calls
    { "block": "LLMJudge" }        // Semantic validation
  ]
}
```

### Retry Logic

```json theme={null}
{
  "pipeline": [
    { "id": "request", "block": "HttpRequest" },
    { "block": "ValidateContent" },
    {
      "block": "Loop",
      "config": {
        "target": "request",
        "maxIterations": 3
      }
    }
  ]
}
```

## Creating Custom Blocks

Don't see what you need? Create custom blocks:

```javascript theme={null}
import { Block } from '@blade47/semantic-test';

export class MyCustomBlock extends Block {
  static get inputs() {
    return {
      required: ['data'],
      optional: ['config']
    };
  }

  static get outputs() {
    return {
      produces: ['result']
    };
  }

  async process(inputs, context) {
    // Your logic here
    return { result: processedData };
  }
}
```

<Card title="Learn More About Custom Blocks" icon="code" href="/advanced/custom-blocks">
  Complete guide to creating and registering custom blocks
</Card>

## Block Composition

Blocks are designed to be composable. Here are common combinations:

<AccordionGroup>
  <Accordion title="Full API Test">
    ```json theme={null}
    HttpRequest → JsonParser → ValidateContent → Assertions
    ```
  </Accordion>

  <Accordion title="AI Response Validation">
    ```json theme={null}
    HttpRequest → StreamParser → ValidateTools → LLMJudge → Assertions
    ```
  </Accordion>

  <Accordion title="Retry with Validation">
    ```json theme={null}
    HttpRequest → ValidateContent → Loop (if failed) → Assertions
    ```
  </Accordion>

  <Accordion title="Mock Testing">
    ```json theme={null}
    MockData → ValidateContent → LLMJudge → Assertions
    ```
  </Accordion>
</AccordionGroup>

## Next Steps

<CardGroup cols={3}>
  <Card title="Explore Each Block" icon="book">
    Click on any block above to see detailed documentation
  </Card>

  <Card title="View Examples" icon="code" href="/examples/basic-api-test">
    See blocks in action with real examples
  </Card>

  <Card title="Create Custom Blocks" icon="hammer" href="/advanced/custom-blocks">
    Extend SemanticTest with your own blocks
  </Card>
</CardGroup>