Anatomy of `manifest.json`

The manifest.json (or manifest.jsonc) file is the absolute core of your extension. It serves as the static blueprint for Mono Studio, declaring your extension's identity, activation events, and UI contributions—all without executing a single line of JavaScript.

tip

JSONC Support : Mono Studio fully supports JSONC (manifest.jsonc). You can safely use single-line (//) and multi-line (/* */) comments inside your manifest to document your configurations.

Let's break down a complete, production-ready manifest for an AI Chat Assistant extension.

1. Core Metadata

These foundational keys define the identity, marketplace presentation, and branding of your extension.

{
  "id": "openai-chat",
  "name": "Mono AI Chat",
  "publisher": "monostudio",
  "version": "1.0.0",
  "description": "Advanced AI coding companion powered by GPT-4o.",
  "category": "Other",
  "tags": ["ai", "copilot", "gpt", "refactor"],
  
  // Branding & Visuals
  "icon": "assets/icon.png",  // Relative path to your 256x256 logo
  "iconColor": "#10a37f",     // Accent background color for the extension card
  "iconLetter": "A",          // Fallback glyph if the icon image fails to load
  
  // Documentation
  "readme": "README.md",
  "changelog": "CHANGELOG.md",
  "license": "LICENSE.txt",

2. Execution & Lifecycle

Mono Studio is highly optimized. Extensions are strictly lazy-loaded and will only execute their main script when specific user actions match the activates array.

  "main": "out/extension.js", // The compiled JavaScript entry point
  "activates": [              // System triggers that boot your extension
    "onLanguage:javascript",
    "onLanguage:typescript",
    "onLanguage:python",
    "onCommand:openai-chat.focusPanel"
  ],

3. The `contributes` Object (Declarative UI)

The contributes block is where the magic happens. It allows you to deeply integrate into the IDE's UI (Menus, Settings, Shortcuts) purely via JSON.

Commands & Keybindings

  "contributes": {
    
    // Commands register metadata to the Command Palette (Ctrl+Shift+P)
    "commands": [
      {
        "id": "openai-chat.inlineSuggest",
        "title": "AI: Trigger Inline Suggestion",
        "icon": "sparkle"
      }
    ],

    // Bind keys to the commands. You can specify OS-specific overrides and focus constraints.
    "keybindings": [
      {
        "command": "openai-chat.inlineSuggest",
        "key": "ctrl+shift+a",
        "mac": "cmd+shift+a",
        "when": "editorTextFocus" // Only active when typing in the code editor
      }
    ],

Context Menus & Actions

Inject items directly into the user's right-click menus or sidebar toolbars.

    "menus": {
      // 1. Editor Context (Right-clicking inside the code editor)
      "editor/context": [
        {
          "command": "openai-chat.explainCodeSelection",
          "label": "Mono AI: Explain Selected Code",
          "icon": "sparkle",
          "when": "editorHasSelection == true", // Evaluated dynamically
          "order": 1
        },
        {
          "type": "separator", // Injects a visual divider line
          "order": 2
        }
      ],
      
      // 2. Tab Bar Context (Right-clicking a file tab at the top)
      "editor/title/context": [
        {
          "command": "openai-chat.documentFile",
          "label": "Generate JSDoc",
          "icon": "book",
          "shortcut": "Ctrl+Alt+D" // Visual hint (does not bind the actual key)
        }
      ],

      // 3. Explorer Context (Right-clicking files/folders in the sidebar)
      "sidebar/files/context": [
        {
          "command": "openai-chat.analyzeArchitecture",
          "label": "Analyze Architecture",
          "icon": "project",
          "when": "workspacePath != null"
        }
      ]
    },

Settings Configuration

Expose user-customizable settings that automatically appear in the Mono Studio Settings UI.

    // Alternatively, you could write: "configuration": "./config/settings.json"
    "configuration": {
      "monoAI.api.key": {
        "type": "string",
        "default": "",
        "description": "Your OpenAI secret API Key."
      },
      "monoAI.model.selection": {
        "type": "string",
        "default": "gpt-4o",
        "enum": ["gpt-4o", "gpt-4-turbo", "deepseek-coder"],
        "description": "Target LLM engine."
      }
    },

Activity Bar & Theming

Inject UI entry points and aesthetic enhancements.

    // Adds a permanent icon to the far-left Activity Bar
    "activityBar": [
      {
        "id": "mono-ai-assistant",
        "title": "AI Copilot",
        "icon": "sparkle",
        "position": "top",
        "priority": 90
      }
    ],

    // Registers custom Code Autocomplete snippet files
    "snippets": [
      { "language": "javascript", "path": "./snippets/js-prompts.json" }
    ],

    // Registers visual UI themes and File Icon packs
    "themes": [
      { "label": "Mono AI Dark", "uiTheme": "vs-dark", "path": "./themes/dark.json" }
    ],
    "iconThemes": [
      { "id": "ai-icons", "label": "Neural Icons", "path": "./icons/theme.json" }
    ]
  } // End of contributes
}

info

Declarative Architecture : By moving UI definitions to the manifest.json, Mono Studio drastically reduces extension boot times. The IDE constructs your Activity Bar, Command Palette, and Context Menus instantly on launch. Your main.js script is only invoked when a user actively clicks one of your registered commands.

1. Core Metadata​

2. Execution & Lifecycle​

3. The contributes Object (Declarative UI)​

Commands & Keybindings​

Context Menus & Actions​

Settings Configuration​

Activity Bar & Theming​