Configuring the Chat Buffer

By default, CodeCompanion provides a "chat" strategy that uses a dedicated Neovim buffer for conversational interaction with your chosen LLM. This buffer can be customized according to your preferences.

Keymaps

You can define or override the default keymaps to send messages, regenerate responses, close the buffer, etc. Example:

require("codecompanion").setup({
  strategies = {
    chat = {
      keymaps = {
        send = {
          modes = { n = "<C-s>", i = "<C-s>" },
        },
        close = {
          modes = { n = "<C-c>", i = "<C-c>" },
        },
        -- Add further custom keymaps here
      },
    },
  },
})

The keymaps are mapped to <C-s> for sending a message and <C-c> for closing in both normal and insert modes.

Variables

Variables are placeholders inserted into the chat buffer (using #). They provide contextual code or information about the current Neovim state. For instance, the built-in #buffer variable sends the current buffer’s contents to the LLM.

You can even define your own variables to share specific content:

require("codecompanion").setup({
  strategies = {
    chat = {
      variables = {
        ["my_var"] = {
          ---Ensure the file matches the CodeCompanion.Variable class
          ---@return string|fun(): nil
          callback = "/Users/Oli/Code/my_var.lua",
          description = "Explain what my_var does",
          opts = {
            contains_code = false,
          },
        },
      },
    },
  },
})

Slash Commands

Slash Commands (invoked with /) let you dynamically insert context into the chat buffer, such as file contents or date/time.

The plugin supports providers like telescope, mini_pick, fzf_lua and snacks (as in snacks.nvim). Please see the Chat Buffer usage section for full details:

require("codecompanion").setup({
  strategies = {
    chat = {
      slash_commands = {
        ["file"] = {
          -- Location to the slash command in CodeCompanion
          callback = "strategies.chat.slash_commands.file",
          description = "Select a file using Telescope",
          opts = {
            provider = "telescope", -- Other options include 'default', 'mini_pick', 'fzf_lua', snacks
            contains_code = true,
          },
        },
      },
    },
  },
})

You can also add your own slash commands:

require("codecompanion").setup({
  strategies = {
    chat = {
      slash_commands = {
        ["git_files"] = {
          description = "List git files",
          ---@param chat CodeCompanion.Chat
          callback = function(chat)
            local handle = io.popen("git ls-files")
            if handle ~= nil then
              local result = handle:read("*a")
              handle:close()
              chat:add_reference({ content = result }, "git", "<git_files>")
            else
              return vim.notify("No git files available", vim.log.levels.INFO, { title = "CodeCompanion" })
            end
          end,
          opts = {
            contains_code = false,
          },
        },
      },
    },
  },
})

Credit to @lazymaniac for the inspiration.

NOTE

You can also point the callback to a lua file that resides within your own configuration

Agents and Tools

Tools perform specific tasks (e.g., running shell commands, editing buffers, etc.) when invoked by an LLM. You can group them into an Agent and both can be referenced with @ when in the chat buffer:

require("codecompanion").setup({
  strategies = {
    chat = {
      agents = {
        ["my_agent"] = {
          description = "A custom agent combining tools",
          system_prompt = "Describe what the agent should do",
          tools = {
            "cmd_runner",
            "editor",
            -- Add your own tools or reuse existing ones
          },
        },
      },
      tools = {
        ["my_tool"] = {
          description = "Run a custom task",
          callback = function(command)
            -- Perform the custom task here
            return "Tool result"
          end,
        },
      },
    },
  },
})

When users introduce the agent @my_agent in the chat buffer, it can call the tools you listed (like @my_tool) to perform tasks on your code.

The callback option for a tool can also be a CodeCompanion.Tool object, which is a table with specific keys that defines the interface and workflow of the tool.

Layout

You can change the appearance of the chat buffer by changing the display.chat.window table in your configuration:

require("codecompanion").setup({
  display = {
    chat = {
      -- Change the default icons
      icons = {
        pinned_buffer = " ",
        watched_buffer = "👀 ",
      },

      -- Alter the sizing of the debug window
      debug_window = {
        ---@return number|fun(): number
        width = vim.o.columns - 5,
        ---@return number|fun(): number
        height = vim.o.lines - 2,
      },

      -- Options to customize the UI of the chat buffer
      window = {
        layout = "vertical", -- float|vertical|horizontal|buffer
        position = nil, -- left|right|top|bottom (nil will default depending on vim.opt.plitright|vim.opt.splitbelow)
        border = "single",
        height = 0.8,
        width = 0.45,
        relative = "editor",
        opts = {
          breakindent = true,
          cursorcolumn = false,
          cursorline = false,
          foldcolumn = "0",
          linebreak = true,
          list = false,
          numberwidth = 1,
          signcolumn = "no",
          spell = false,
          wrap = true,
        },
      },

      ---Customize how tokens are displayed
      ---@param tokens number
      ---@param adapter CodeCompanion.Adapter
      ---@return string
      token_count = function(tokens, adapter)
        return " (" .. tokens .. " tokens)"
      end,
    },
  },
}),

Diff

NOTE

Currently the plugin only supports native Neovim diff or mini.diff

If you utilize the @editor tool, then the plugin can update a given chat buffer. A diff will be created so you can see the changes made by the LLM.

There are a number of diff settings available to you:

require("codecompanion").setup({
  display = {
    diff = {
      enabled = true,
      close_chat_at = 240, -- Close an open chat buffer if the total columns of your display are less than...
      layout = "vertical", -- vertical|horizontal split for default provider
      opts = { "internal", "filler", "closeoff", "algorithm:patience", "followwrap", "linematch:120" },
      provider = "default", -- default|mini_diff
    },
  },
}),

UI

User and LLM Roles

The chat buffer places user and LLM responses under a H2 header. These can be customized in the configuration:

require("codecompanion").setup({
  strategies = {
    chat = {
      roles = {
        ---The header name for the LLM's messages
        ---@type string|fun(adapter: CodeCompanion.Adapter): string
        llm = function(adapter)
          return "CodeCompanion (" .. adapter.formatted_name .. ")"
        end,

        ---The header name for your messages
        ---@type string
        user = "Me",
      }
    }
  }
})

By default, the LLM's responses will be placed under a header such as CodeCompanion (DeepSeek), leveraging the current adapter in the chat buffer. This option can be in the form of a string or a function that returns a string. If you opt for a function, the first parameter will always be the adapter from the chat buffer.

The user role is currently only available as a string.

Markdown Rendering

As the Chat Buffer uses markdown as its syntax, you can use popular rendering plugins to improve the UI:

render-markdown.nvim

{
  "MeanderingProgrammer/render-markdown.nvim",
  ft = { "markdown", "codecompanion" }
},

markview.nvim

{
  "OXY2DEV/markview.nvim",
  lazy = false,
  opts = {
    preview = {
      filetypes = { "markdown", "codecompanion" },
      ignore_buftypes = {},
    },
  },
},

Additional Options

There are also a number of other options that you can customize:

require("codecompanion").setup({
  display = {
    chat = {
      intro_message = "Welcome to CodeCompanion ✨! Press ? for options",
      show_header_separator = false, -- Show header separators in the chat buffer? Set this to false if you're using an external markdown formatting plugin
      separator = "─", -- The separator between the different messages in the chat buffer
      show_references = true, -- Show references (from slash commands and variables) in the chat buffer?
      show_settings = false, -- Show LLM settings at the top of the chat buffer?
      show_token_count = true, -- Show the token count for each response?
      start_in_insert_mode = false, -- Open the chat buffer in insert mode?
    },
  },
}),