claude-code-sender.nvim

Send selected code from Neovim to Claude Code with rich context — file path, line numbers, LSP diagnostics, git diff, and project instructions.

Works with cmux and tmux.

Features

• Send selection / current line / entire buffer to Claude Code
• Prompt templates — pick "Fix the bug", "Write tests", etc. from a menu
• LSP diagnostics — send error messages alongside the relevant code
• Git diff — send current unstaged changes to Claude Code
• CLAUDE.md auto-injection — project instructions are automatically prepended to every prompt
• Auto-detects Claude Code pane/surface
• Supports both cmux and tmux

Requirements

• Neovim >= 0.9.0
• cmux or tmux
• Claude Code running in a separate pane

Installation

Using lazy.nvim:

{
  "hayawata3626/claude-code-sender.nvim",
  opts = {},
  keys = {
    { "<leader>ac", mode = "v", desc = "Send selection to Claude Code" },
    { "<leader>al", desc = "Send current line to Claude Code" },
    { "<leader>ab", desc = "Send buffer to Claude Code" },
    { "<leader>ae", mode = { "n", "v" }, desc = "Send diagnostics to Claude Code" },
    { "<leader>ag", desc = "Send git diff to Claude Code" },
    { "<leader>at", mode = "v", desc = "Send with template to Claude Code" },
  },
}

Usage

Basic

1. Open Neovim and Claude Code in separate panes (same cmux workspace or tmux session)
2. Select code in Visual mode and press <leader>ac to send with file context

The text is sent in this format:

src/app/page.tsx:10-25

```tsx
// selected code here

### Prompt templates (`<leader>at`)

Select code in Visual mode and press `<leader>at`. A picker appears:

Send to Claude Code:

Explain this code Fix the bug Write tests Refactor Add error handling Review for security Add comments/docs Optimize performance

The chosen instruction is prepended to your code block before sending.

### LSP diagnostics (`<leader>ae`)

Press `<leader>ae` on a line (or select a range) to send the diagnostic errors together with the code:

LSP Diagnostics (src/app/page.tsx:10)

ERROR (10): Property 'foo' does not exist on type 'Bar'

src/app/page.tsx:10

const x = bar.foo

### Git diff (`<leader>ag`)

Press `<leader>ag` to send the current unstaged changes:

Git Diff (unstaged changes)

diff --git a/src/app/page.tsx b/src/app/page.tsx
...

### CLAUDE.md auto-injection

If a `CLAUDE.md` file exists anywhere up the directory tree from your current working directory, its contents are automatically prepended to every prompt:

Project Instructions (CLAUDE.md)

---

src/app/page.tsx:10-25

// your code

Disable this with `project_context = { inject_claude_md = false }`.

## Configuration

```lua
require("claude-code-sender").setup({
  -- Terminal multiplexer: "auto" | "cmux" | "tmux"
  multiplexer = "auto",

  cmux = {
    bin = "cmux", -- auto-detected from PATH, or set full path
    surface_id = nil, -- auto-detect, or set e.g. "surface:50"
  },

  tmux = {
    bin = "tmux",
    pane_id = nil, -- auto-detect, or set e.g. "%3"
  },

  -- Project context
  project_context = {
    inject_claude_md = true, -- prepend CLAUDE.md to every prompt
  },

  -- Add custom templates (appended after built-in ones)
  templates = {
    { label = "Add JSDoc comments", prompt = "Please add JSDoc comments to the following code.\n\n" },
  },

  -- Keymaps (set any to false to disable)
  keymaps = {
    send_selection     = "<leader>ac", -- Visual mode
    send_line          = "<leader>al", -- Normal mode
    send_buffer        = "<leader>ab", -- Normal mode
    send_diagnostics   = "<leader>ae", -- Normal + Visual mode
    send_git_diff      = "<leader>ag", -- Normal mode
    send_with_template = "<leader>at", -- Visual mode
  },

  -- Custom format function for the code block
  format = function(file, start_line, end_line, filetype, text)
    return string.format("%s:%d-%d\n\n```%s\n%s\n```", file, start_line, end_line, filetype, text)
  end,
})

Keymaps

Key	Mode	Description
<leader>ac	Visual	Send selection to Claude Code
<leader>al	Normal	Send current line to Claude Code
<leader>ab	Normal	Send entire buffer to Claude Code
<leader>ae	Normal / Visual	Send LSP diagnostics + code to Claude Code
<leader>ag	Normal	Send git diff (unstaged) to Claude Code
<leader>at	Visual	Pick a prompt template, then send selection

Troubleshooting

"Could not find Claude Code surface/pane"

Make sure Claude Code is fully started (showing the > prompt) in a pane within the same cmux workspace or tmux session.

cmux binary not found

If cmux is not in your PATH, set the full path:

opts = {
  cmux = {
    bin = "/Applications/cmux.app/Contents/Resources/bin/cmux",
  },
}

License

MIT