A full feature build inside an existing vibe-coded app, start to finish: a plan-first conversation, two shipped phases, a progression system, two new MCP tools, and a glossary page that only exists because testing surfaced a gap the code itself never needed to close. Less about dumbbells, more about what it actually looks like to build something substantial into an app that already works.
Sometimes your agent’s turn just ends with no result — no error, no output, nothing. Nudging it usually gets you the answer that was there the whole time. It’s tempting to write that off as a UX hiccup. Sometimes it’s a real bug, and finding out is part of the fun of vibe coding. A walkthrough of why that’s worth investigating, when it crosses the line into “file this,” and how to do it well — using a hanging GitHub tool call as the live example.
A personal gaming-settings tracker built end-to-end with an agent: 28 curated profiles, a JSON API, an MCP server, and a dropdown that quietly pointed at data that didn’t exist. Five lessons from building it solo.
The fitness tracker MCP server was a test run. This week I added the same thing to vibescoder.dev — 16 tools that let any agent list posts, publish drafts, check analytics, trigger deploys, cross-post to Dev.to, and troubleshoot the live site. Here’s the build, the architectural decisions, and what it’s like when the agent that built the feature can immediately use it.
I asked an agent to security-audit my fitness tracker after wiring MCP into it. It found nineteen things. I fixed them all in four neat batches. Then the dashboard went empty, Google sign-in died, and the real bugs turned out to be the ones the audit couldn’t see — a middleware file that had been silently doing nothing for months, and an OAuth client that never existed in any project I owned.
I built a Model Context Protocol server into the fitness tracker I vibe coded a year ago, wired it through Vercel and Coder workspaces, and ended the afternoon asking my Discord bot what my last workout was. Here’s the build, the wrong turn into Coder’s AI Bridge, the workaround, and how the same endpoint now serves Claude Desktop, Codex, Coder Agents, and OpenClaw.
While waiting for massive open source models to download, I tackled the homelab backlog: custom domain for my Coder instance via Cloudflare Tunnel, security hardening (with a gotcha that could kill your AI search visibility), and wiring up MCP servers to give agents superpowers.