Build and Deploy an AI Coding Agent | Cursor Clone with Next.js 16 | Full Course 2026

Quick Overview

The tutorial focuses on building out the AI conversation system for Polaris, an AI-powered IDE clone, by implementing message cancellation functionality, conversation history dialogue, and setting up the groundwork for AI agent tool execution using Ingest Agent Kit and Convex system queries/mutations.

Key Points: The developer implemented a route to cancel a message by creating an API endpoint that queries Convex for all processing messages in a project and sends an ingest message forward/cancel event to stop the background job. A new Convex mutation, updateMessageStatus, was created to explicitly set a message's status to 'cancelled' after the background job is aborted. The conversation sidebar now explicitly checks if a message status is 'cancelled' to render 'Request cancelled' instead of content, preventing users from spamming new requests while one is processing. To prevent token overspending, the API route for sending a new message now checks for any existing processing messages for the project, cancels them, and updates their status before creating the new user message. The history dialogue component, PastConversationsDialogue, was created using command components to allow users to search and select past conversations, setting the selected conversation ID upon selection. Extensive system queries and mutations were added to Convex for agent tool preparation, including getRecentMessages, updateConversationTitle, getProjectFiles, updateFile, and recursive deleteFile.

Context: This video is Part Two of a full course building Polaris, an AI-powered IDE similar to Cursor, using Next.js 16, Convex for the database, and Ingest for the agent framework. The current focus is completing the conversation system by implementing necessary features left over from Part One, specifically message cancellation flow and conversation history display, before diving into full AI agent tool execution.

Detailed Analysis

The session begins by addressing unfinished tasks: implementing message cancellation and building the history dialogue. To enable cancellation, a new API route, /api/messages/cancel, is created. This route uses a Convex query, getProcessingMessages (newly implemented in system.ts using the optimized byProjectStatus index), to find any messages marked as 'processing' for the current project. It then programmatically cancels the associated Ingest background job by sending an ingest message forward/cancel event, passing the message ID. Crucially, it then calls a new Convex mutation, updateMessageStatus, to update the database record to 'cancelled'. The conversation sidebar component is updated to conditionally render 'Request cancelled' if the message status is cancelled, and handle cancellation explicitly when the user clicks the cancel indicator if processing is active. Furthermore, the message creation API route is enhanced to automatically cancel all currently processing requests for the project before creating a new user message, ensuring only one background job runs per project to prevent token overspending. Next, the history dialogue is implemented using a PastConversationsDialogue component, allowing users to load and select past conversations via a command menu, which updates the selected conversation ID. Finally, the developer prepares for AI agent implementation by installing @ingest/agent-kit and defining numerous system queries and mutations in Convex system.ts, such as getRecentMessages (for context), updateConversationTitle, and file management tools (getFileByID, updateFile, createFile, createFiles, createFolder, renameFile, and recursive deleteFile) needed for the agent's tool loop.