Function migrateAgentParamsToMessages

apps/sim/serializer/index.ts:95–145

* Helper function to migrate agent block params from old format to messages array * Transforms systemPrompt/userPrompt into messages array format * Only migrates if old format exists and new format doesn't (idempotent)

(
  params: Record<string, any>,
  subBlocks: Record<string, any>,
  blockId: string
)

 * Only migrates if old format exists and new format doesn't (idempotent)
 */
function migrateAgentParamsToMessages(
  params: Record<string, any>,
  subBlocks: Record<string, any>,
  blockId: string
): void {
  // Only migrate if old format exists and new format doesn't
  if ((params.systemPrompt || params.userPrompt) && !params.messages) {
    logger.info('Migrating agent block from legacy format to messages array', {
      blockId,
      hasSystemPrompt: !!params.systemPrompt,
      hasUserPrompt: !!params.userPrompt,
    })

    const messages: any[] = []

    // Add system message first (industry standard)
    if (params.systemPrompt) {
      messages.push({
        role: 'system',
        content: params.systemPrompt,
      })
    }

    // Add user message
    if (params.userPrompt) {
      let userContent = params.userPrompt

      // Handle object format (e.g., { input: "..." })
      if (typeof userContent === 'object' && userContent !== null) {
        if ('input' in userContent) {
          userContent = userContent.input
        } else {
          // If it's an object but doesn't have 'input', stringify it
          userContent = JSON.stringify(userContent)
        }
      }

      messages.push({
        role: 'user',
        content: String(userContent),
      })
    }

    // Set the migrated messages in subBlocks
    subBlocks.messages = {
      id: 'messages',
      type: 'messages-input',
      value: messages,
    }
  }
}

export class Serializer {
  serializeWorkflow(