Copilot Chat for Vim

Copilot Chat functionality without having to leave Vim.

Nvim folks will be able to use CopilotChat.nvim for a similar experience.

Table of Contents

• Requirements
• Installation
• Setup
• Commands
• Key Mappings
• Features
• Custom Configuration
• Troubleshooting
• Contributing

Requirements

• Vim 9.0+
• Nerd Fonts (Optional for pretty icons)
• Active GitHub Copilot subscription

Installation

Using vim-plug, Vundle, Pathogen, Vim 8+ packages, or any other plugin manager.

vim-plug (Recommended)

Add to your .vimrc:

call plug#begin()
Plug 'DanBradbury/copilot-chat.vim'
call plug#end()

filetype plugin indent on

Then run :PlugInstall in Vim.

Vundle

Add to your .vimrc:

call vundle#begin()
Plugin 'DanBradbury/copilot-chat.vim'
call vundle#end()

filetype plugin indent on

Then run :PluginInstall in Vim.

Pathogen

Clone the repository:

git clone https://github.com/DanBradbury/copilot-chat.vim.git ~/.vim/bundle/copilot-chat.vim

Add to your .vimrc:

call pathogen#infect()
syntax on
filetype plugin indent on

Vim 8+ packages

Clone the repository:

git clone https://github.com/DanBradbury/copilot-chat.vim.git ~/.vim/pack/plugins/start/copilot-chat.vim

Add to your .vimrc:

filetype plugin indent on

Setup

1. After installing the plugin, the first time you launch Vim you'll be presented with the device registration page in your default browser
2. Follow the steps on the page and paste the Device Code when prompted
3. Once completed, press <Enter> back in Vim to complete the registration process
4. Start chatting with Copilot (:CopilotChatOpen, :CopilotChat simple question, etc.)
5. 🎉 You're ready to go!

Commands

Command	Description
:CopilotChat <input>	Launch a new Copilot chat with your input as the initial prompt
:CopilotChatOpen	Open a new Copilot chat window (default: vsplit right)
:CopilotChatFocus	Focus the currently active chat window
:CopilotChatReset	Reset the current chat window
:CopilotChatClose	Close the current chat window
:CopilotChatConfig	Open config.json for default settings
:CopilotChatModels	View available models / select active model
:CopilotChatSave [name]	Save chat history (uses timestamp if no name provided)
:CopilotChatLoad [name]	Load chat history (shows list if no name provided)
:CopilotChatList	List all saved chat histories
:CopilotChatSetActive [bufnr]	Set the active chat window (defaults to current buffer)
:CopilotChatUsage	Show Copilot usage stats

Key Mappings

Plugin Keys

Key	Description
<Plug>CopilotChatAddSelection	Copy selected text into active chat buffer

Default Mappings (in Chat Window)

Mode	Key	Action
Normal	<CR>	Submit current prompt
Normal (Models popup)	<CR> or <Space>	Select the highlighted model

Example User Mappings

The plugin intentionally avoids setting global key mappings to prevent conflicts. Here are some suggested mappings for your .vimrc:

" Open a new Copilot Chat window
nnoremap <leader>cc :CopilotChatOpen<CR>

" Focus existing chat window
nnoremap <leader>cf :CopilotChatFocus<CR>

" Add visual selection to chat
vmap <leader>ca <Plug>CopilotChatAddSelection

" Reset chat conversation
nnoremap <leader>cr :CopilotChatReset<CR>

Features

Autocomplete Macros

/tab all Macro

Type /tab all in the chat window to automatically expand into a list of all open tabs (excluding the current buffer) with their filenames prefixed by #file:. If no other tabs are found, No other tabs found will be inserted.

#file: Macro

Type #file: in the chat window for intelligent file path autocomplete:

• Suggests files from the current Git repository (if in a Git project)
• Falls back to all files in the current working directory
• Excludes directories, only shows files
• Filters based on text typed after #file:

Example: Typing #file:src/ shows files in the src/ directory.

Model Selection

Use :CopilotChatModels to open a popup menu of available models. Press <Enter> or <Space> to select. New chats will use the selected model.

Add Selection to Chat

Visually select code and use <Plug>CopilotChatAddSelection (or your custom mapping) to add it to the active chat window inside a filetype-specific code block.

Chat History

Save and restore your chat conversations:

Saving:

:CopilotChatSave my-refactoring-session
:CopilotChatSave  " Uses timestamp if no name provided

Loading:

:CopilotChatLoad my-refactoring-session
:CopilotChatLoad  " Shows list of available histories
:CopilotChatList  " View all saved chat histories

History files are stored in ~/.vim/copilot-chat/history/ as JSON files.

Prompt Templates

Save and reuse frequently used prompts. In the chat window, start a line with > PROMPT_NAME to expand the template.

Managing Prompts

1. Open config: :CopilotChatConfig
2. Add prompts to config.json:

{
  "model": "gpt-4",
  "prompts": {
    "explain": "Explain how this code works in detail:",
    "refactor": "Suggest improvements and refactoring for this code:",
    "docs": "Generate documentation for this code:",
    "test": "Write unit tests for this code:",
    "review": "Review this code for bugs and best practices:"
  }
}

Example Usage

> explain

function validateUser() {
  // code to validate
}

The > explain will be replaced with the full template text before sending to Copilot.

Custom Configuration

Customize behavior by setting global variables in your .vimrc:

Configuration Options

Variable	Default	Description
g:copilot_chat_window_position	'right'	Split direction: 'right', 'left', 'top', 'bottom'
g:copilot_chat_disable_mappings	0	Set to 1 to disable default chat window mappings
g:copilot_chat_create_on_add_selection	1	Create new chat when adding selection if none exists
g:copilot_chat_jump_to_chat_on_add_selection	1	Jump to chat window after adding selection
g:copilot_reuse_active_chat	1	Reuse active chat window instead of creating new ones
g:copilot_chat_data_dir	~/.vim/copilot-chat/	Directory for plugin data storage
g:copilot_chat_open_on_toggle	1	Set to 0 to prevent opening on toggle
g:copilot_list_chat_buffer	0	Set to 1 to list copilot-chat buffers
g:copilot_chat_message_history_limit	20	Maximum messages sent to API (lower = faster)
g:copilot_chat_syntax_debounce_ms	300	Debounce delay for syntax highlighting (ms)
g:copilot_chat_file_cache_timeout	5	Cache timeout for file completion (seconds)

Example Configurations

Open chats in horizontal split at bottom:

let g:copilot_chat_window_position = 'bottom'

Performance tuning for long chat sessions:

" Limit context for faster responses
let g:copilot_chat_message_history_limit = 10

" Reduce CPU usage on slower machines
let g:copilot_chat_syntax_debounce_ms = 500

" Reduce system calls for large projects
let g:copilot_chat_file_cache_timeout = 10

Customize selection behavior:

" Don't create new chat when adding selection
let g:copilot_chat_create_on_add_selection = 0

" Stay in current window after adding selection
let g:copilot_chat_jump_to_chat_on_add_selection = 0

Troubleshooting

"Resource not accessible by integration"

This error means the logged-in GitHub account does not have an active Copilot subscription. Please:

1. Verify your GitHub Copilot subscription at https://github.com/settings/copilot
2. Ensure your subscription is active and not expired
3. Try logging out and back in to refresh your credentials

Chat window not responding

• Check if you're authenticated: Restart Vim and check for authentication prompts
• Verify network connectivity
• Try resetting the chat with :CopilotChatReset

File autocomplete not working

• Ensure you're in a valid directory
• For Git projects, verify the repository is initialized
• Try adjusting g:copilot_chat_file_cache_timeout for better performance

Contributing

Please see the contribution guide for more information.

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