Self Modifying Code

Self-Modifying Code

Rule

The agent can edit the app's own source code — components, routes, styles, scripts. This is a feature, not a bug. Design your app expecting this.

Why

An agent-native app isn't just an app the agent can use — it's an app the agent can change. The agent can fix bugs, add features, adjust styles, and restructure code. This makes the agent a true collaborator, not just an operator.

Modification Taxonomy

Not all modifications are equal. Use this to decide what level of care is needed:

Tier 4 includes all of the following — not only editing package source:

• Files under node_modules/@agent-native/* (core, dispatch, scheduling, …)
• pnpm.overrides, overrides, resolutions, or patchedDependencies that target any @agent-native/* package
• pnpm patch, pnpm patch-commit, or local package patch artifacts for any dependency
• Invented "dispatch/core behavior" shims meant to paper over a version skew or failed upgrade

This does not prohibit intentional app-owned UI customization. When public props and composition are insufficient, the customizing-agent-native skill uses agent-native eject to transfer the smallest supported unit from the installed package into the app. The ejected unit must keep public runtime contracts and must not replace Core auth, DB, actions, agent execution, or transport behavior. Manual copying is only the fallback described by an unknown third-party package's add-style blueprint.

When an older branch needs current packages, use agent-native upgrade (see the upgrade-agent-native skill). If upgrade or typecheck fails, fix app code or stop and ask — do not patch the framework.

Git Checkpoint Pattern

Before modifying source code (Tier 2+), create a rollback point:

1. Commit or stash current state
2. Make the edit
3. Run pnpm typecheck && pnpm lint
4. If verification fails → revert with git checkout -- <file>
5. If verification passes → continue

This ensures the agent can experiment without breaking the app.

Designing for Agent Editability

Make your app easy for the agent to understand and modify:

Expose UI state via data-* attributes so the agent knows what's selected:

const el = document.documentElement;
el.dataset.currentView = view;
el.dataset.selectedId = selectedItem?.id || "";

Expose richer context via window.__appState for complex state:

(window as any).__appState = {
  selectedId: id,
  currentLayout: layout,
  itemCount: items.length,
};

Use configuration-driven rendering — Extract visual decisions (colors, layouts, sizes) into JSON config files in data/. The agent can modify the config (Tier 1) instead of the component source (Tier 2).

Keep localized copy in catalogs — When editing visible UI copy, labels, toasts, empty states, prompts, or formatting, update the English source catalog. Read the optional internationalization skill and update additional catalogs only when translations.locales in agent-native.config.ts includes them.

Don't

• Don't modify .env files or files containing secrets
• Don't modify @agent-native/core, @agent-native/dispatch, or other @agent-native/* package internals (including under node_modules)
• Don't confuse readable package source with app-owned code: use customizing-agent-native and agent-native eject for supported ownership transfer
• Don't use pnpm patch / pnpm patch-commit, commit patches/ artifacts, or add pnpm.patchedDependencies to "make the app run" after a version bump
• Don't add pnpm.overrides / patchedDependencies / resolutions for @agent-native/* to paper over a broken upgrade
• Don't invent local dispatch/core behavior overrides when upgrade fails — run npx @agent-native/core@latest upgrade, then fix app-level errors only
• Don't modify .agents/skills/ or AGENTS.md unless explicitly requested
• Don't skip the typecheck/lint step after editing source code
• Don't make source changes without a git checkpoint to roll back to

Related Skills

• upgrade-agent-native — supported path to bring an older app/workspace current
• customizing-agent-native — configure, compose, or eject installed features safely
• storing-data — Tier 1 modifications (data files) are the safest and most common
• actions — The agent can create or modify actions to add new capabilities
• delegate-to-agent — Self-modification requests come through the agent chat
• real-time-sync — Database writes trigger change events to update the UI
• internationalization — UI copy, language catalogs, locale switching, and RTL-safe edits