> For the complete documentation index, see [llms.txt](https://docs.vntranslator.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.vntranslator.com/advanced/custom-mt/components.md).

# Components

This is a configuration section of [Custom MT](/advanced/custom-mt.md). Components are declared as objects within the configuration:

```json
{
    "components": {
        "preTranslation": {},
        "postTranslation": {},
        "contextMemory": {},
        "usageChecker": {},
        "interceptorRequest": {}
    }
}
```

### preTranslation

Processes the source text before sending it to the translation service.

* **allowLineBreaks**: `boolean`
* **excludeStrings**: `string`
* **regexpMatch**: `string`
* **regexpReplace**: `string`

```json
{
    "components": {
        "preTranslation":{
            "allowLineBreaks": true,
            "regexpReplace": "[\"\\n\", \"g\", \"\\\\n \"]"
        }
    }
}
```

### postTranslation

Processes the translated text after receiving it from the translation service.

* **regexpMatch**: `string`
* **regexpReplace**: `string`

```json
{
    "components": {
        "postTranslation": {
            "regexpReplace": "[\"\\\\\\\\n\", \"g\", \"\\n\"]"
        }
    }
}
```

### contextMemory

Maintains context history for AI/LLM translations, allowing the model to reference previous dialogue for improved coherence and accuracy.

**Required Parameters**

* **schema**: `Array of objects` <{type: string, name: string, default: string|number|bool}>
* **formBuilder**: `Array of objects` <{type: string, form: string, name: string, default: string|number}>
* **components**: `object` - Component reference to schema name \<schema:string>

```json
{
    "schema": {
        { "type": "boolean", "name": "contextMemory.status", "default": true },
        { "type": "string", "name": "contextMemory.initial_prompt", "default": "" },
        { "type": "string", "name": "contextMemory.system_template", "default": "" },
        { "type": "string", "name": "contextMemory.user_template", "default": "[{ \"role\": \"user\", \"parts\":[{\"text\":\"$SOURCE_TEXT\"}] }]" },
        { "type": "string", "name": "contextMemory.assistant_template", "default": "[{ \"role\": \"model\", \"parts\":[{\"text\":\"$TRANSLATED_TEXT\"}] }]" },
        { "type": "string", "name": "contextMemory.data_source", "default": "new_translation" },
        { "type": "number", "name": "contextMemory.max_entries", "default": "1" },
    },
    "formBuilder": {
        { "type": "string", "form": "textarea", "width": "450", "name": "contextMemory.user_template", "default": "", "title": "User Template" },
        { "type": "string", "form": "textarea", "width": "450", "name": "contextMemory.assistant_template", "default": "", "title": "Assistant Template" },
        { "type": "string", "form": "select", "name": "contextMemory.data_source", "title": "Context Source", "default": "TM",
            "options": [
                { "name": "New Translation History", "value": "new_translation" },
                { "name": "Translation Memory", "value": "TM" }                
            ]
        },
        { "type": "number", "form": "range", "name": "contextMemory.max_entries", "title": "Max Context Entries", "default": "1", "min": "1", "max": "256", "step": "1" }

    },
    "components": {
        "contextMemory": {
            "schema": "contextMemory"
        }
    }
}
```

### usageChecker

* **interval**: `number` - Interval in milliseconds between usage checks
* **format**: `string` - Display format for usage information
* **request**: `object` - Request configuration for checking usage:
  * **method**: `string` - HTTP method (`"http_get"`, `"http_post"`)
  * **url:** `string` - API endpoint URL for usage information
  * **body**: `object` <mark style="color:$warning;">(optional)</mark> - Request body for POST requests
  * **options**: `object` <mark style="color:$warning;">(optional)</mark> - Additional request options:
    * **headers:** `object` - Custom request headers
  * **responseCountQuery:** `string` - JSON path to extract current usage count
  * **responseLimitQuery:** `string` - JSON path to extract usage limit

```json
{
    "components": {
        "usageChecker": {
            "interval": 60000,
            "format": "( $COUNT / $LIMIT )",
            "request": {
                "method": "http_get",
                "url": "https://api.deepl.com/v2/usage?auth_key=$API_KEY",
                "responseCountQuery": "character_count",
                "responseLimitQuery": "character_limit"
            }        
        }
    }
}
```

### interceptorRequest

Modifies the source text before sending it to the translation service.

* **prependSourceText**: `object` - Adds text before the source text:
  * **status**: `boolean` - Enable or disable prepending
  * **value**: `string` - Text to prepend
* **appendSourceText**: `object` - Adds text after the source text:
  * **status**: `boolean` - Enable or disable appending
  * **value**: `string` - Text to append
* **replaceSourceText**: `object` - Replaces the entire source text

```json
{
    "schema": {
        { "type": "boolean", "name": "interceptorRequest.prependSourceText", "default": false },
        { "type": "string", "name": "prompt", "default": "Translate the following text from $SOURCE_LANG to $TARGET_LANG: " }
    },
    "components": {
        "interceptorRequest":{
            "prependSourceText": {
                "status": false,
                "value": "$PROMPT"
            }         
        }
    }
}
```