Mentor MCP Server

/** * Represents a prompt template with placeholders for dynamic values. */ export interface PromptTemplate { template: string; systemPrompt?: string; } /** * Represents variables that can be used in a prompt template. */ export type PromptVariables = Record<string, string | number | boolean>; /** * Fills a prompt template with provided variables. * * @param template - The prompt template containing placeholders * @param variables - Object containing values for the placeholders * @returns The filled prompt string * @throws Error if required variables are missing */ export function fillPromptTemplate(template: string, variables: PromptVariables): string { // Find all placeholders in the template const placeholders = template.match(/\{([^}]+)\}/g) || []; // Create a map of required variables const requiredVars = new Set( placeholders.map(p => p.slice(1, -1)) // Remove { and } ); // Check if all required variables are provided const missingVars = Array.from(requiredVars).filter(v => !(v in variables)); if (missingVars.length > 0) { throw new Error(`Missing required variables: ${missingVars.join(', ')}`); } // Replace all placeholders with their values return template.replace(/\{([^}]+)\}/g, (_, key) => { const value = variables[key]; return String(value); }); } /** * Sanitizes user input to prevent prompt injection attacks. * * @param input - The user input to sanitize * @returns Sanitized input string */ export function sanitizeInput(input: string): string { // Remove any attempt to break out of the current context return input .replace(/```/g, '\\`\\`\\`') // Escape code blocks .replace(/\{/g, '\\{') // Escape template literals .replace(/\}/g, '\\}') .trim(); } /** * Creates a complete prompt by combining system prompt, template, and variables. * * @param promptTemplate - The prompt template object * @param variables - Variables to fill in the template * @returns Complete prompt string */ export function createPrompt( promptTemplate: PromptTemplate, variables: PromptVariables ): string { const filledTemplate = fillPromptTemplate(promptTemplate.template, variables); if (promptTemplate.systemPrompt) { return `${promptTemplate.systemPrompt}\n\n${filledTemplate}`; } return filledTemplate; } /** * Validates a prompt to ensure it doesn't exceed maximum length. * * @param prompt - The prompt to validate * @param maxLength - Maximum allowed length (default: 4000) * @returns boolean indicating if the prompt is valid */ export function validatePrompt(prompt: string, maxLength: number = 4000): boolean { return prompt.length <= maxLength; } /** * Truncates a prompt to fit within maximum length while preserving meaning. * * @param prompt - The prompt to truncate * @param maxLength - Maximum allowed length * @returns Truncated prompt string */ export function truncatePrompt(prompt: string, maxLength: number = 4000): string { if (prompt.length <= maxLength) { return prompt; } // Try to truncate at a sentence boundary const truncated = prompt.slice(0, maxLength); const lastSentence = truncated.match(/.*[.!?]/); if (lastSentence) { return lastSentence[0]; } // If no sentence boundary found, truncate at last complete word const lastSpace = truncated.lastIndexOf(' '); return truncated.slice(0, lastSpace) + '...'; }