functhis

Imported from xmazu/functhis (AGENTS.md). Install upstream with npx skills add xmazu/functhis. Copyright stays with the author.

Ultracite Code Standards

This project uses Ultracite, a zero-config preset that enforces strict code quality standards through automated formatting and linting.

Quick Reference

• Format code: bun x ultracite fix
• Check for issues: bun x ultracite check
• Diagnose setup: bun x ultracite doctor

Oxlint + Oxfmt (the underlying engine) provides robust linting and formatting. Most issues are automatically fixable.

Git Commits

Follow Conventional Commits. Every commit message:

<type>(<optional scope>): <description>

• Use lowercase type and imperative description (what the commit does, not what you did)
• Keep the description under 72 characters; put detail in the body
• Do not end the subject with a period
• Use a body when the why is not obvious from the subject
• Breaking changes: BREAKING CHANGE: in the body, or ! after the type/scope (feat(api)!: ...)

Types:

Examples: feat(cli): add device login, fix(auth): reject special-use CIMD hosts, docs: describe terraform and wrangler split.

Core Principles

Write code that is accessible, performant, type-safe, and maintainable. Focus on clarity and explicit intent over brevity.

Type Safety & Explicitness

• Use explicit types for function parameters and return values when they enhance clarity
• Prefer unknown over any when the type is genuinely unknown
• Use const assertions (as const) for immutable values and literal types
• Leverage TypeScript's type narrowing instead of type assertions
• Use meaningful variable names instead of magic numbers - extract constants with descriptive names

Modern JavaScript/TypeScript

• Use arrow functions for callbacks and short functions
• Prefer for...of loops over .forEach() and indexed for loops
• Use optional chaining (?.) and nullish coalescing (??) for safer property access
• Prefer template literals over string concatenation
• Use destructuring for object and array assignments
• Use const by default, let only when reassignment is needed, never var

Async & Promises

• Always await promises in async functions - don't forget to use the return value
• Use async/await syntax instead of promise chains for better readability
• Handle errors appropriately in async code with try-catch blocks
• Don't use async functions as Promise executors

React & JSX

• Use function components over class components
• Call hooks at the top level only, never conditionally
• Specify all dependencies in hook dependency arrays correctly
• Use the key prop for elements in iterables (prefer unique IDs over array indices)
• Nest children between opening and closing tags instead of passing as props
• Don't define components inside other components
• Use semantic HTML and ARIA attributes for accessibility:
  • Provide meaningful alt text for images
  • Use proper heading hierarchy
  • Add labels for form inputs
  • Include keyboard event handlers alongside mouse events
  • Use semantic elements (<button>, <nav>, etc.) instead of divs with roles

Error Handling & Debugging

• Remove console.log, debugger, and alert statements from production code
• Throw Error objects with descriptive messages, not strings or other values
• Use try-catch blocks meaningfully - don't catch errors just to rethrow them
• Prefer early returns over nested conditionals for error cases

Code Organization

• Keep functions focused and under reasonable cognitive complexity limits
• Extract complex conditions into well-named boolean variables
• Use early returns to reduce nesting
• Prefer simple conditionals over nested ternary operators
• Group related code together and separate concerns

Security

• Add rel="noopener" when using target="_blank" on links
• Avoid dangerouslySetInnerHTML unless absolutely necessary
• Don't use eval() or assign directly to document.cookie
• Validate and sanitize user input

Performance

• Avoid spread syntax in accumulators within loops
• Use top-level regex literals instead of creating them in loops
• Prefer specific imports over namespace imports
• Avoid barrel files (index files that re-export everything)
• Use proper image components (e.g., Next.js <Image>) over <img> tags

Framework-Specific Guidance

Next.js:

• Use Next.js <Image> component for images
• Use next/head or App Router metadata API for head elements
• Use Server Components for async data fetching instead of async Client Components

React 19+:

• Use ref as a prop instead of React.forwardRef

Solid/Svelte/Vue/Qwik:

• Use class and for attributes (not className or htmlFor)

Testing

• Before adding or changing integration tests, read docs/integration-tests.md and tests/integration/README.md
• Write assertions inside it() or test() blocks
• Avoid done callbacks in async tests - use async/await instead
• Don't use .only or .skip in committed code
• Keep test suites reasonably flat - avoid excessive describe nesting

When Oxlint + Oxfmt Can't Help

Oxlint + Oxfmt's linter will catch most issues automatically. Focus your attention on:

1. Business logic correctness - Oxlint + Oxfmt can't validate your algorithms
2. Meaningful naming - Use descriptive names for functions, variables, and types
3. Architecture decisions - Component structure, data flow, and API design
4. Edge cases - Handle boundary conditions and error states
5. User experience - Accessibility, performance, and usability considerations
6. Documentation - Add comments for complex logic, but prefer self-documenting code

Design documents

apps/web/DESIGN.md and apps/console/DESIGN.md are visual language only: color, type, spacing, motion, surfaces, and general UX principles.

Never add product features, page sections, component inventories, implementation recipes, or copy decks to those files. Product behavior belongs in vision.md and architecture.md; UI structure belongs in code. When the look changes, update tokens and principles - not a catalog of widgets.

Do not restyle apps/console from the web design file, or apps/web from the console design file.

Monorepo placement

Put code in packages/ only when it is shared - imported from more than one app or package (e.g. web + console, or packages/auth + apps/web). If a module has a single consumer, keep it under that app (e.g. apps/web/src/server/…) until a second consumer exists, then extract.

packages/api is the shared oRPC surface: procedures and types that more than one app will call (web, console, MCP HTTP later). Do not add app-only procedures there. See architecture.md for the full rule.

Do not add to packages/ “for organization” or “might be reused later” without a second consumer today - that spreads coupling and makes ownership unclear.

Unused and barrel-only code

Remove dead code; do not grow public surfaces “just in case.”

• Run bun run knip (also part of bun run check) before finishing a change. Fix or delete what it reports: unused files, unused exports, unused dependencies.
• Barrel files (index.ts that re-export symbols) must not be the only reason something exists. If a symbol is exported from a package entry or barrel but never imported outside that barrel chain, delete the symbol (and trim the barrel), not “leave it for the API.”
• Prefer direct imports to the defining module over re-exporting through barrels when only one app needs the code (see also Avoid barrel files under Performance above).

Most formatting and common issues are automatically fixed by Oxlint + Oxfmt. Run bun x ultracite fix before committing to ensure compliance. Commit with a Conventional Commits subject as above.