SillyTavern/src/prompt-converters.js

/**
 * Convert a prompt from the ChatML objects to the format used by Claude.
 * @param {object[]} messages Array of messages
 * @param {boolean}  addAssistantPostfix Add Assistant postfix.
 * @param {string}   addAssistantPrefill Add Assistant prefill after the assistant postfix.
 * @param {boolean}  withSysPromptSupport Indicates if the Claude model supports the system prompt format.
 * @param {boolean}  useSystemPrompt Indicates if the system prompt format should be used.
 * @param {boolean}  excludePrefixes Exlude Human/Assistant prefixes.
 * @param {string}   addSysHumanMsg Add Human message between system prompt and assistant.
 * @returns {string} Prompt for Claude
 * @copyright Prompt Conversion script taken from RisuAI by kwaroran (GPLv3).
 */
function convertClaudePrompt(messages, addAssistantPostfix, addAssistantPrefill, withSysPromptSupport, useSystemPrompt, addSysHumanMsg, excludePrefixes) {

    //Prepare messages for claude.
    //When 'Exclude Human/Assistant prefixes' checked, setting messages role to the 'system'(last message is exception).
    if (messages.length > 0) {
        if (excludePrefixes) {
            messages.slice(0, -1).forEach(message => message.role = 'system');
        } else {
            messages[0].role = 'system';
        }
        //Add the assistant's message to the end of messages.
        if (addAssistantPostfix) {
            messages.push({
                role: 'assistant',
                content: addAssistantPrefill || '',
            });
        }
        // Find the index of the first message with an assistant role and check for a "'user' role/Human:" before it.
        let hasUser = false;
        const firstAssistantIndex = messages.findIndex((message, i) => {
            if (i >= 0 && (message.role === 'user' || message.content.includes('\n\nHuman: '))) {
                hasUser = true;
            }
            return message.role === 'assistant' && i > 0;
        });
        // When 2.1+ and 'Use system prompt' checked, switches to the system prompt format by setting the first message's role to the 'system'.
        // Inserts the human's message before the first the assistant one, if there are no such message or prefix found.
        if (withSysPromptSupport && useSystemPrompt) {
            messages[0].role = 'system';
            if (firstAssistantIndex > 0 && addSysHumanMsg && !hasUser) {
                messages.splice(firstAssistantIndex, 0, {
                    role: 'user',
                    content: addSysHumanMsg,
                });
            }
        } else {
            // Otherwise, use the default message format by setting the first message's role to 'user'(compatible with all claude models including 2.1.)
            messages[0].role = 'user';
            // Fix messages order for default message format when(messages > Context Size) by merging two messages with "\n\nHuman: " prefixes into one, before the first Assistant's message.
            if (firstAssistantIndex > 0 && !excludePrefixes) {
                messages[firstAssistantIndex - 1].role = firstAssistantIndex - 1 !== 0 && messages[firstAssistantIndex - 1].role === 'user' ? 'FixHumMsg' : messages[firstAssistantIndex - 1].role;
            }
        }
    }

    // Convert messages to the prompt.
    let requestPrompt = messages.map((v, i) => {
        // Set prefix according to the role. Also, when "Exclude Human/Assistant prefixes" is checked, names are added via the system prefix.
        let prefix = {
            'assistant': '\n\nAssistant: ',
            'user': '\n\nHuman: ',
            'system': i === 0 ? '' : v.name === 'example_assistant' ? '\n\nA: ' : v.name === 'example_user' ? '\n\nH: ' : excludePrefixes && v.name ? `\n\n${v.name}: ` : '\n\n',
            'FixHumMsg': '\n\nFirst message: ',
        }[v.role] ?? '';
        // Claude doesn't support message names, so we'll just add them to the message content.
        return `${prefix}${v.name && v.role !== 'system' ? `${v.name}: ` : ''}${v.content}`;
    }).join('');

    return requestPrompt;
}

/**
 * Convert ChatML objects into working with Anthropic's new Messaging API.
 * @param {object[]} messages Array of messages
 * @param {string}   prefillString User determined prefill string
 * @param {boolean}  useSysPrompt See if we want to use a system prompt
 * @param {string}   humanMsgFix Add Human message between system prompt and assistant.
 * @param {string}   charName Character name
 * @param {string}   userName User name
 */
function convertClaudeMessages(messages, prefillString, useSysPrompt, humanMsgFix, charName = '', userName = '') {
    let systemPrompt = '';
    if (useSysPrompt) {
        // Collect all the system messages up until the first instance of a non-system message, and then remove them from the messages array.
        let i;
        for (i = 0; i < messages.length; i++) {
            if (messages[i].role !== 'system') {
                break;
            }
            if (userName && messages[i].name === 'example_user') {
                messages[i].content = `${userName}: ${messages[i].content}`;
            }
            if (charName && messages[i].name === 'example_assistant') {
                messages[i].content = `${charName}: ${messages[i].content}`;
            }
            systemPrompt += `${messages[i].content}\n\n`;
        }

        messages.splice(0, i);

        // Check if the first message in the array is of type user, if not, interject with humanMsgFix or a blank message.
        // Also prevents erroring out if the messages array is empty.
        if (messages.length === 0 || (messages.length > 0 && messages[0].role !== 'user')) {
            messages.unshift({
                role: 'user',
                content: humanMsgFix || '[Start a new chat]',
            });
        }
    }
    // Now replace all further messages that have the role 'system' with the role 'user'. (or all if we're not using one)
    messages.forEach((message) => {
        if (message.role === 'system') {
            if (userName && message.name === 'example_user') {
                message.content = `${userName}: ${message.content}`;
            }
            if (charName && message.name === 'example_assistant') {
                message.content = `${charName}: ${message.content}`;
            }
            message.role = 'user';
        }
    });

    // Shouldn't be conditional anymore, messages api expects the last role to be user unless we're explicitly prefilling
    if (prefillString) {
        messages.push({
            role: 'assistant',
            content: prefillString.trimEnd(),
        });
    }

    // Since the messaging endpoint only supports user assistant roles in turns, we have to merge messages with the same role if they follow eachother
    // Also handle multi-modality, holy slop.
    let mergedMessages = [];
    messages.forEach((message) => {
        const imageEntry = message.content?.[1]?.image_url;
        const imageData = imageEntry?.url;
        const mimeType = imageData?.split(';')?.[0].split(':')?.[1];
        const base64Data = imageData?.split(',')?.[1];

        // Take care of name properties since claude messages don't support them
        if (message.name) {
            if (Array.isArray(message.content)) {
                message.content[0].text = `${message.name}: ${message.content[0].text}`;
            } else {
                message.content = `${message.name}: ${message.content}`;
            }
            delete message.name;
        }

        if (mergedMessages.length > 0 && mergedMessages[mergedMessages.length - 1].role === message.role) {
            if (Array.isArray(message.content)) {
                if (Array.isArray(mergedMessages[mergedMessages.length - 1].content)) {
                    mergedMessages[mergedMessages.length - 1].content[0].text += '\n\n' + message.content[0].text;
                } else {
                    mergedMessages[mergedMessages.length - 1].content += '\n\n' + message.content[0].text;
                }
            } else {
                if (Array.isArray(mergedMessages[mergedMessages.length - 1].content)) {
                    mergedMessages[mergedMessages.length - 1].content[0].text += '\n\n' + message.content;
                } else {
                    mergedMessages[mergedMessages.length - 1].content += '\n\n' + message.content;
                }
            }
        } else {
            mergedMessages.push(message);
        }
        if (imageData) {
            mergedMessages[mergedMessages.length - 1].content = [
                { type: 'text', text: mergedMessages[mergedMessages.length - 1].content[0]?.text || mergedMessages[mergedMessages.length - 1].content },
                {
                    type: 'image', source: {
                        type: 'base64',
                        media_type: mimeType,
                        data: base64Data,
                    },
                },
            ];
        }
    });

    return { messages: mergedMessages, systemPrompt: systemPrompt.trim() };
}

/**
 * Convert a prompt from the ChatML objects to the format used by Google MakerSuite models.
 * @param {object[]} messages Array of messages
 * @param {string} model Model name
 * @returns {object[]} Prompt for Google MakerSuite models
 */
function convertGooglePrompt(messages, model) {
    // This is a 1x1 transparent PNG
    const PNG_PIXEL = 'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=';

    const visionSupportedModels = [
        'gemini-1.0-pro-vision-latest',
        'gemini-1.5-pro-latest',
        'gemini-pro-vision',
    ];

    const isMultimodal = visionSupportedModels.includes(model);
    let hasImage = false;

    const contents = [];
    messages.forEach((message, index) => {
        // fix the roles
        if (message.role === 'system') {
            message.role = 'user';
        } else if (message.role === 'assistant') {
            message.role = 'model';
        }

        // similar story as claude
        if (message.name) {
            if (Array.isArray(message.content)) {
                message.content[0].text = `${message.name}: ${message.content[0].text}`;
            } else {
                message.content = `${message.name}: ${message.content}`;
            }
            delete message.name;
        }

        //create the prompt parts
        const parts = [];
        if (typeof message.content === 'string') {
            parts.push({ text: message.content });
        } else if (Array.isArray(message.content)) {
            message.content.forEach((part) => {
                if (part.type === 'text') {
                    parts.push({ text: part.text });
                } else if (part.type === 'image_url' && isMultimodal) {
                    parts.push({
                        inlineData: {
                            mimeType: 'image/png',
                            data: part.image_url.url,
                        },
                    });
                    hasImage = true;
                }
            });
        }

        // merge consecutive messages with the same role
        if (index > 0 && message.role === contents[contents.length - 1].role) {
            contents[contents.length - 1].parts[0].text += '\n\n' + parts[0].text;
        } else {
            contents.push({
                role: message.role,
                parts: parts,
            });
        }
    });

    // pro 1.5 doesn't require a dummy image to be attached, other vision models do
    if (isMultimodal && model !== 'gemini-1.5-pro-latest' && !hasImage) {
        contents[0].parts.push({
            inlineData: {
                mimeType: 'image/png',
                data: PNG_PIXEL,
            },
        });
    }

    return contents;
}

/**
 * Convert a prompt from the ChatML objects to the format used by Text Completion API.
 * @param {object[]} messages Array of messages
 * @returns {string} Prompt for Text Completion API
 */
function convertTextCompletionPrompt(messages) {
    if (typeof messages === 'string') {
        return messages;
    }

    const messageStrings = [];
    messages.forEach(m => {
        if (m.role === 'system' && m.name === undefined) {
            messageStrings.push('System: ' + m.content);
        }
        else if (m.role === 'system' && m.name !== undefined) {
            messageStrings.push(m.name + ': ' + m.content);
        }
        else {
            messageStrings.push(m.role + ': ' + m.content);
        }
    });
    return messageStrings.join('\n') + '\nassistant:';
}

module.exports = {
    convertClaudePrompt,
    convertClaudeMessages,
    convertGooglePrompt,
    convertTextCompletionPrompt,
};