Three models independently audited the same pinned code in isolated workspaces, blind to each other. Two produced reports. Opus 5 found the bug that actually mattered. Fable 5 was blocked twice, at the same spot.
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.
What started as a Thursday Thoughts hot take on the OpenAI/Hugging Face eval-sandbox breach turned into a research sprint: a survey of existing AI agent containment standards, a deep look at the closest one we found (the Agent Sandbox Taxonomy), an attempt to score the actual incident against it using nothing but public disclosures, and a plan to validate then run Coder itself through the assessment.
The May audit closed clean. Since then we shipped an MCP server, a Slack integration, and a shareable-snippet image generator -- three new pieces of attack surface that postdated every finding in that audit. A fresh scan against the same categories found 8 issues across the old surface and the new. Three phases, three commits, about an hour, one repo.
Coder 2.34 shipped User Secrets — per-user credential storage that injects into every workspace automatically. We upgraded, audited 29 secrets across four projects, and found exactly two that belonged there. Here’s how we decided, how we migrated, and what we cleaned up along the way.
I built a trip planning site for my F1 Montreal group. Then I ripped out every hardcoded value, added a setup wizard, ran a security audit, and open-sourced it. Here’s what it takes to turn a single-purpose vibe coded app into something anyone can fork and deploy.
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.
Someone vibe coded an app with Google AI Studio. The Gemini API key shipped in the client-side JavaScript bundle. Google suspended the project. Here’s why every AI coding tool gets this wrong, why regular audits are the only real defense, and what you can do before it happens to you.
Three AI agents audited the blog and produced three different reports. Closing them out was its own job — triage, phasing, verification, and ten commits across two repos with zero build failures. Here’s the remediation arc, what shipped, what got deferred, and what the process revealed about working through someone else’s audit.
I open-sourced my blog for Giscus comments and immediately found a gutted .gitignore, an exposed server URL, and all my unpublished drafts on GitHub. Here’s how I split code from content without changing a single line of application code.
