Dev builds MMO RPG chat panel using spec-driven agentic coding

Web Dev Cody streams active development on an MMO RPG side project, focusing on implementing a chat panel feature through agentic coding. After encountering bugs with an initial vibe-coding pass, he shifts to a spec-driven development workflow: writing a Markdown file that fully documents the feature's requirements and edge cases before re-engaging the AI agent. The chat panel spec covers behaviors such as opening and closing with the Tab key, displaying previous messages with timestamps (e.g., "5 seconds ago", "4 minutes ago") using a library like `date-fns`, tracking user input with backspace support, and sending messages on Enter. He also notes the need to remove an older keybinding (the Y key) that previously triggered chat input.

He mentions other AI tools like GPT and Opus as alternatives depending on the task, but expresses a preference for Composer for side-project work due to its interactive feel compared to longer autonomous runs.

The stream touches on broader agentic coding philosophy — the creator recommends starting with a thorough spec document to reduce agent errors, and describes occasionally using plan mode in Composer before committing to a full implementation run. He mentions other AI tools like GPT and Opus as alternatives depending on the task, but expresses a preference for Composer for side-project work due to its interactive feel compared to longer autonomous runs. On the art side, he explains that while the base tile set is a free Creative Commons asset, many in-game items — including auction house assets and crafting sprites — are AI-generated placeholders, with plans to refine them later or learn Aseprite for custom sprite work.

Key facts

1. 01Web Dev Cody is building an MMO RPG side project using agentic coding tools, primarily Cursor's Composer.
2. 02After hitting bugs with vibe coding, he pivots to spec-driven development — writing a Markdown requirements doc before engaging the agent.
3. 03The chat panel spec includes: Tab to open/close, message history with relative timestamps, input tracking with backspace, and Enter to send.
4. 04He plans to use a third-party library like `date-fns` for relative timestamp formatting.
5. 05An existing Y-key chat trigger is being removed and replaced with the Tab-key interaction.
6. 06The project's base tile set is a free Creative Commons asset; many in-game item sprites are AI-generated placeholders.
7. 07He prefers Composer for interactive side-project work over longer-running autonomous agent sessions.