The latest articles on Forem by Juha Kangas (@valuecodes). https://forem.com/valuecodes https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F818046%2F2d93d8ea-7545-4465-9430-b0fe2edb5c99.jpeg https://forem.com/valuecodes en Juha Kangas Sun, 11 Jan 2026 14:14:58 +0000 https://forem.com/valuecodes/back-to-basics-a-solid-foundation-for-using-ai-coding-agents-in-a-monorepo-3c26 https://forem.com/valuecodes/back-to-basics-a-solid-foundation-for-using-ai-coding-agents-in-a-monorepo-3c26 <p>AI agents ship code fast — and they also ship entropy: inconsistent patterns, noisy diffs, and PRs that look done until CI disagrees. The fix isn’t "let the agent rewrite everything." It’s making correctness and consistency non-negotiable, so the agent can’t drift even when it improvises. You get there by building a boring, solid baseline the agent can reliably work within.</p> <h2> Tooling </h2> <p>If you only enforce three things, enforce these:</p> <p><strong>Typecheck (correctness)</strong><br> Agents generate plausible code. TypeScript tells you if it typechecks — which eliminates a huge class of "looks right" mistakes. Make <code>pnpm typecheck</code> a hard gate locally and in CI.</p> <p><strong>Lint (consistency)</strong><br> AI mixes styles and patterns. ESLint reduces drift by enforcing consistent patterns and catching common footguns. Gate on <code>pnpm lint</code>.</p> <p><strong>Format (reviewability)</strong><br> AI often leaves unformatted code. Prettier keeps diffs readable. Gate on <code>pnpm format:check</code> in CI. Claude Code can auto-format via a PostToolUse hook but regardless of editor/agent, CI still enforces format:check.</p> <h2> AGENTS.md docs </h2> <p>Tooling enforces code; <code>AGENTS.md</code> sets expectations and boundaries for agent behavior.</p> <p>A monorepo should have a root <code>AGENTS.md</code> that defines:</p> <ol> <li>the repo structure</li> <li>the standard commands</li> <li>shared rules and boundaries</li> </ol> <p>Each app/package should have its own <code>AGENTS.md</code> tailored to local context:</p> <ol> <li>what it is and what it owns</li> <li>dependencies on other packages</li> <li>footguns / gotchas</li> </ol> <p>Docs should stay in sync via a docs sync workflow (e.g. updating docs when adding a new command like <code>pnpm clean</code>). In my experience, Codex is great at mechanical doc updates, while Claude tends to shine on bigger changes — and this repo makes it easy to compare what each agent is best at.</p> <p>Repo/template: <a href="https://github.com/valuecodes/agentic-monorepo-starter" rel="noopener noreferrer">https://github.com/valuecodes/agentic-monorepo-starter</a></p> <p>Disclosure: This article was created with the help of AI.</p> tooling monorepo ai typescript