The latest articles on DEV Community by Mat Leal (@mat_leal_54019661bc21ab55). https://dev.to/mat_leal_54019661bc21ab55 https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4078168%2Fd4e78dcb-aa6f-4c1c-9912-0a206b305c35.png https://dev.to/mat_leal_54019661bc21ab55 en Mat Leal Fri, 14 Aug 2026 20:18:28 +0000 https://dev.to/mat_leal_54019661bc21ab55/i-built-mosaic-a-local-planning-studio-that-makes-codex-output-reviewable-dj1 https://dev.to/mat_leal_54019661bc21ab55/i-built-mosaic-a-local-planning-studio-that-makes-codex-output-reviewable-dj1 <p>I’m Matheus, the maker of Mosaic.</p> <p>While building products with agents, I wanted the planning work to leave behind more than a useful chat transcript. Product decisions should remain inspectable, revisable, and explicit before implementation begins.</p> <p>Mosaic is my attempt at that workflow. Its current <strong>Plan Studio</strong> alpha runs locally on Apple Silicon Macs and works with a compatible Codex installation.</p> <p>A Plan can contain:</p> <ul> <li>durable Brief, Requirements, Architecture, UX, Test Scenario, and Delivery Plan documents</li> <li>self-contained interactive HTML prototypes</li> <li>comments anchored to documents or individual prototype elements</li> <li>candidate diffs and validation results</li> <li>immutable revisions after explicit approval</li> </ul> <p>The core loop is: ask Codex to revise a Plan, inspect the candidate changes, comment or discard them, and approve only the version worth preserving.</p> <p><a href="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Farticles%2Fzf7zu9tbxc62vxvleswi.webp" class="article-body-image-wrapper"><img src="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Farticles%2Fzf7zu9tbxc62vxvleswi.webp" alt="Mosaic Plan Studio showing Codex chat, product documents, revision controls, and an interactive HTML prototype" width="800" height="501"></a></p> <p><em>Plan-scoped Codex chat, product documents, and a working HTML design in one workspace.</em></p> <p>This is a deliberately limited alpha. It is free to evaluate, unsigned and not notarized, has no cloud sync, and does not yet implement code or handle deployment. Generated artifacts still require human review.</p> <p><a href="https://mosaic-site-wine.vercel.app/" rel="noopener noreferrer">https://mosaic-site-wine.vercel.app/</a></p> <p>If you tried this on a real feature, which review checkpoint would matter most before implementation: document diffs, prototype comments, validation results, or approval history?</p> showdev ai productivity openai