A built-in Message processor that processes a received Message for JSON contents.

When successful, the assistant message's JSON contents are processed into a map and set on processed_content. No additional validation or processing of the data is done in by this processor.

When JSON data is expected but not received, or the received JSON is invalid or incomplete, a new user Message struct is returned with a text error message for the LLM so it can try again to correct the error and return a valid response.

There are multiple ways to extract JSON content.

When the JSON data is reliably returned as the only response, this extracts it to an Elixir Map:

message = Message.new_assistant!(%{content: "{"value": 123}"})

# process the message for JSON content
{:cont, updated_chain, updated_message} =
  JsonProcessor.run(chain, message)

The updated message will be an assistant message where content is a map:

updated_message.content
#=> %{"value" => 123}

Some models are unable to reliably return a JSON response without adding some commentary. For that situation, instruct the model how to format the JSON content. Depending on the model, one of these formats may work better than another:

# bracketing the data with XML tags
<json>
{"value": 123}
</json>

# markdown style code fences with json language
```json
{"value": 123}
```

# markdown style code fences (no language)
```
{"value": 123}
```

When the LLM adds commentary with the data, it may appear like this:

The answer to your question in JSON is:

```json
{"value": 123}
```

We can still extract the JSON data in a situation like this. We provide a Regex to use for extracting the data from whatever starting and ending text the LLM was instructed to use.

Examples:

~r/<json>(.*?)</json>/s
~r/```json(.*?)```/s
~r/```(.*?)```/s

The "```json" formatted one is processed like this:

{:cont, updated_chain, updated_message} =
  JsonProcessor.run(chain, message, ~r/```json(.*?)```/s)