inspector/AGENTS.md

Inspector V2

This is an application for inspecting MCP servers. Has three incarnations, Web, TUI, and CLI.

Project Structure

inspector/
├── clients/                            
│   ├── web/                            # Web client code
│   ├── cli/                            # CLI client code
│   ├── tui/                            # TUI client code
│   ├── launcher/                       # Shared launcher 
├── core/                               # Shared core code
├── soecification/                      # Build specification
...

Maintenance Rules

Keep documentation files up to date

• When adding, removing, renaming, or changing the purpose of any file or folder, update the corresponding entry in the main README.md and/or the related clients/*/README.md
• When the structure of the project, the tech stack, or the developer setup changes, update appropriate README.md files with the details.
• When adding new commands, dependencies, or architectural patterns, update the relevant sections of appropriate README.md files as well.
• When rules for implementation and testing change, update this file AGENTS.md

Always test new or modified coderea

• Ensure all code has corresponding tests
• Ensure test coverage for each file is at least 90%
• In unit tests that expect error output, suppress it from the console

Responding to Code Reviews

• When asked to respond to a code review of a PR,
  • it is not necessary to implement all suggestions
  • you are free to implement suggestions in a different way or to ignore if there is a good reason
  • after making the changes, respond to each review comment with what was done (or why it was ignored)

Lint-fixed, Formatted code

• Ensure linting and formatting are applied after every change
• ALWAYS do npm run format, npm run lint, npm run typecheck, npm run test and npm run build before pushing any changes

Typescript instructions

• Use TypeScript for all new code
• Follow TypeScript best practices and coding standards
• NEVER use 'any' as a type
• NEVER suppress error types (e.g., no-unused-vars, no-explicit-any) in the typescript or eslint configuration as a way of satisfying the linter or compiler.
• Utilize type annotations and interfaces to improve code clarity and maintainability
• Leverage TypeScript's type inference and static analysis features for better code quality and refactoring
• Use type guards and type assertions to handle potential type mismatches and ensure type safety
• Take advantage of TypeScript's advanced features like generics, type aliases, and conditional types to write more expressive and reusable code
• Regularly review and refactor TypeScript code to ensure it remains well-structured and adheres to evolving best practices

React instructions

• UI Components
  • We are using the Mantine component library for UI.
  • Instructions are at https://mantine.dev/llms.txt
  • Avoid using div and other basic HTML elements for layout purposes.
  • Prefer Mantine's Box, Group, and Stack components for layout.
  • Use Mantine's theme and styling utilities to ensure a consistent and responsive design.
  • NEVER use inline styles on a component.
  • NEVER use raw hex values (#ddd, #94a3b8, etc.) or rgba() literals for colors in component props or theme files. Use --inspector-* CSS custom properties defined in App.css :root (e.g., c: 'var(--inspector-text-primary)'). If no existing token fits, add one to :root first.
  • NEVER add a CSS class to a Mantine component when the styles can instead be expressed as component props or a theme variant. CSS classes are a last resort.
  • PREFER component props (via .withProps()) to CSS for behavioral and visual styles.
  • PREFER defining styles as theme variants (via Component.extend() in src/theme/<Component>.ts) over CSS classes. Each Mantine component with custom variants has its own file in src/theme/, exporting a Theme<Name> constant. The barrel src/theme/index.ts re-exports them all and theme.ts imports from the barrel. Flat CSS properties (margin, padding, background, border, color, font-size, etc.) belong in the theme. Only pseudo-selectors, nested child selectors, keyframes, and native HTML element styles belong in App.css.
  • App.css must contain ONLY styles that cannot be expressed in the Mantine theme: @keyframes, pseudo-selectors (:hover, :focus), cross-component hover relationships, nested child-element selectors for third-party HTML output (e.g. ReactMarkdown), and styles for native HTML elements (img, iframe). When refactoring a component, actively move any flat CSS properties out of App.css and into theme variants or .withProps() constants.
  • NEVER use inline code; instead extract to functions in the same file, exported or located in a shared location if immediately reusable.
  • In a component's file, for sub-components:
    • ALWAYS use Mantine components for layout and content, configured with props for styling and behavior.
    • ALWAYS declare a subcomponent as a named constant using .withProps() if it has two or more props.
    • NEVER use Box for subcomponent constants — Box does not support .withProps(). Use Group, Stack, Flex, Text, Paper, UnstyledButton, or Image instead. Pick the component that best matches the purpose: Paper for bordered/surfaced containers, Text for any text or content wrapper, Stack/Group/Flex for layout.
    • NEVER use a CSS class on a subcomponent constant when the styles can be expressed as a Mantine theme variant instead. Define variants in src/theme/<Component>.ts using Component.extend({ styles: (_theme, props) => { ... } }) and reference them with variant="variantName" on the component or in .withProps().
    • CSS classes are ONLY acceptable on subcomponents for styles that cannot be expressed as flat CSS-in-JS properties in the theme — specifically: pseudo-selectors (:hover, :focus), cross-component hover relationships (.parent:hover .child), nested child-element selectors (.wrapper p, .wrapper code), @keyframes definitions, and native HTML elements (img, iframe) that are not Mantine components.
    • When a theme variant needs a CSS class for nested/pseudo selectors, use classNames in the theme extension to auto-assign it — never add className manually in JSX for theme-styled components.
    • Example — subcomponent constant with withProps:

      const CardContent = Group.withProps({
        flex: 1,
        align: 'flex-start',
        justify: 'space-between',
        wrap: 'nowrap',
      });
      return <CardContent> ... </CardContent>
    

    • Example — theme variant with auto-assigned className for nested selectors:

      // src/theme/Paper.ts
      export const ThemePaper = Paper.extend({
        classNames: (_theme, props) => {
          if (props.variant === 'message') return { root: 'message' };
          return {};
        },
        styles: (_theme, props) => {
          if (props.variant === 'message') {
            return { root: { padding: '1.5rem', borderRadius: 12 } };
          }
          return { root: {} };
        },
      }),
    
      // Component.tsx
      const MessageContainer = Paper.withProps({ variant: 'message' });