feat(integrations): support ClaudeCodeTreeAdd in snacks.nvim pickers (#192) (#269)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Thomas Kosiewski <tk@coder.com>

Author: ThomasK33

README.md

@@ -60,7 +60,7 @@ When Anthropic released Claude Code, they only supported VS Code and JetBrains.
       "<leader>as",
       "<cmd>ClaudeCodeTreeAdd<cr>",
       desc = "Add file",
-      ft = { "NvimTree", "neo-tree", "oil", "minifiles", "netrw" },
+      ft = { "NvimTree", "neo-tree", "oil", "minifiles", "netrw", "snacks_picker_list" },
     },
     -- Diff management
     { "<leader>aa", "<cmd>ClaudeCodeDiffAccept<cr>", desc = "Accept diff" },
@@ -212,7 +212,8 @@ Configure the plugin with the detected path:
 1. **Launch Claude**: Run `:ClaudeCode` to open Claude in a split terminal
 2. **Send context**:
    - Select text in visual mode and use `<leader>as` to send it to Claude
-   - In `nvim-tree`/`neo-tree`/`oil.nvim`/`mini.nvim`, press `<leader>as` on a file to add it to Claude's context
+   - In `nvim-tree`/`neo-tree`/`oil.nvim`/`mini.nvim`, or a focused snacks picker list / the Snacks Explorer sidebar, press `<leader>as` on a file to add it to Claude's context
+   - For modal snacks pickers (`Snacks.picker.files()`/`grep()`), which keep focus in the input box, bind a picker action that calls `require("claudecode").send_at_mention(...)` for the selected item(s) — the [claude-fzf.nvim](#-claude-fzfnvim) community extension does the equivalent for `fzf-lua`
 3. **Let Claude work**: Claude can now:
    - See your current file and selections in real-time
    - Open files in your editor

fixtures/snacks-picker/README.md

@@ -0,0 +1,85 @@
+# snacks-picker fixture — triage for issue #192
+
+Reproduces and explores [#192](https://github.com/coder/claudecode.nvim/issues/192):
+make adding the **highlighted/selected file in a snacks.nvim picker** to Claude's
+context work, instead of failing with:
+
+```
+[ClaudeCode] [command] [ERROR] ClaudeCodeTreeAdd: Not in a supported tree buffer (current filetype: snacks_picker_list)
+```
+
+Unlike the tree-explorer integrations (`nvim-tree`, `neo-tree`, `oil`,
+`mini.files`, `netrw`), a snacks **picker** is a modal fuzzy finder. Its window
+layout is:
+
+| window | filetype              | buftype  | usual focus                       |
+| ------ | --------------------- | -------- | --------------------------------- |
+| box    | `snacks_layout_box`   | `nofile` | —                                 |
+| list   | `snacks_picker_list`  | `nofile` | only when you `<Tab>`/cycle to it |
+| input  | `snacks_picker_input` | `prompt` | **default (insert mode)**         |
+
+`:ClaudeCodeTreeAdd` only sees `snacks_picker_list` when the **list** window is
+focused — but the picker normally keeps focus in the **input** box. That is why
+the idiomatic fix is an in-picker _action bound to a key_, not an ex-command.
+
+Note: `Snacks.explorer()` is built on the picker and also uses the
+`snacks_picker_list` filetype, so the same code path covers both.
+
+## Run it
+
+```bash
+source fixtures/nvim-aliases.sh
+vv snacks-picker
+```
+
+Then `:ClaudeCodeStart` (or it auto-starts), and:
+
+- `<leader>ff` → files picker, `<leader>fg` → grep picker.
+
+### Path A — zero-change WORKAROUND (works on stock claudecode.nvim)
+
+`lua/plugins/snacks.lua` registers a custom picker action `claude_add` bound to
+`<c-o>` in both the input and list windows. From the picker (input box, insert
+mode):
+
+1. Type to filter; optionally `<Tab>` to multi-select several files.
+2. Press `<c-o>` → the selected files (or the one under the cursor) are sent to
+   Claude via the public `require("claudecode").send_at_mention()` API, and the
+   picker closes.
+
+This needs **no changes to claudecode.nvim**. It mirrors how the community
+`claude-fzf.nvim` plugin integrates fzf-lua.
+
+### Path B — built-in command path
+
+The in-core `snacks_picker_list` handler (`integrations._get_snacks_picker_selection`)
+makes `:ClaudeCodeTreeAdd` work when the list window is focused:
+
+1. Open a picker, `<Tab>` to focus/cycle to the **list** window (filetype becomes
+   `snacks_picker_list`).
+2. `:ClaudeCodeTreeAdd` (or `<leader>at`) → selected/cursor files are added.
+
+## Deterministic, headless proof (no Claude client needed)
+
+The behavior was validated headlessly:
+
+```text
+# Without the snacks_picker_list handler (the issue #192 state), list focused:
+focused_filetype:  snacks_picker_list
+dispatch_error:    Not in a supported tree buffer (current filetype: snacks_picker_list)
+
+# With the in-core handler, 2 files multi-selected:
+handler_basenames: alpha.lua,beta.lua
+dispatch_files: 2   err: nil
+
+# Key-bound action (Path A), 2 files multi-selected:
+send_at_mention_results: alpha.lua=true,beta.lua=true
+```
+
+To reproduce headlessly, a small throwaway harness (not committed) opens a picker
+with `Snacks.picker.files({ cwd = ... })`, `vim.wait`s until
+`Snacks.picker.get()` returns a picker with items, focuses the list window, then
+calls `require("claudecode.integrations").get_selected_files_from_tree()` and
+inspects the returned paths. The committed unit test
+`tests/unit/snacks_picker_integration_spec.lua` covers the same logic
+deterministically with mocked snacks.

fixtures/snacks-picker/example/alpha.lua

@@ -0,0 +1,8 @@
+-- example/alpha.lua — a file to highlight/select in the snacks picker.
+local M = {}
+
+function M.greet(name)
+  return "hello, " .. (name or "world")
+end
+
+return M

fixtures/snacks-picker/example/beta.lua

@@ -0,0 +1,8 @@
+-- example/beta.lua — a second file, to test multi-select (<Tab>) in the picker.
+local M = {}
+
+function M.add(a, b)
+  return a + b
+end
+
+return M

fixtures/snacks-picker/init.lua

@@ -0,0 +1 @@
+require("config.lazy")

fixtures/snacks-picker/lazy-lock.json

@@ -0,0 +1,5 @@
+{
+  "lazy.nvim": { "branch": "main", "commit": "85c7ff3711b730b4030d03144f6db6375044ae82" },
+  "snacks.nvim": { "branch": "main", "commit": "882c996cf28183f4d63640de0b4c02ec886d01f2" },
+  "tokyonight.nvim": { "branch": "main", "commit": "cdc07ac78467a233fd62c493de29a17e0cf2b2b6" }
+}

fixtures/snacks-picker/lua/config/lazy.lua

@@ -0,0 +1,37 @@
+-- Bootstrap lazy.nvim
+local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
+if not (vim.uv or vim.loop).fs_stat(lazypath) then
+  local lazyrepo = "https://github.com/folke/lazy.nvim.git"
+  local out = vim.fn.system({ "git", "clone", "--filter=blob:none", "--branch=stable", lazyrepo, lazypath })
+  if vim.v.shell_error ~= 0 then
+    vim.api.nvim_echo({
+      { "Failed to clone lazy.nvim:\n", "ErrorMsg" },
+      { out, "WarningMsg" },
+      { "\nPress any key to exit..." },
+    }, true, {})
+    vim.fn.getchar()
+    os.exit(1)
+  end
+end
+vim.opt.rtp:prepend(lazypath)
+
+vim.g.mapleader = " "
+vim.g.maplocalleader = "\\"
+
+-- Resolve the claudecode.nvim checkout that owns this fixture.
+-- XDG_CONFIG_HOME is set to the `fixtures/` dir by the `vv` launcher, so the
+-- repository root is its parent. This makes the fixture load the local plugin
+-- copy (including git worktrees) without relying on lazy's default dev path.
+local repo_root = vim.fn.fnamemodify(vim.env.XDG_CONFIG_HOME or vim.fn.getcwd(), ":h")
+vim.g.claudecode_dev_dir = repo_root
+
+require("lazy").setup({
+  spec = {
+    { import = "plugins" },
+  },
+  install = { colorscheme = { "habamax" } },
+  checker = { enabled = false },
+})
+
+vim.keymap.set("n", "<leader>l", "<cmd>Lazy<cr>", { desc = "Lazy Plugin Manager" })
+vim.keymap.set("t", "<Esc><Esc>", "<C-\\><C-n>", { desc = "Exit terminal mode (double esc)" })

fixtures/snacks-picker/lua/plugins/dev-claudecode.lua

@@ -0,0 +1,22 @@
+-- Development configuration for claudecode.nvim with the snacks.nvim picker.
+-- Loads the local plugin checkout (resolved in lua/config/lazy.lua) via `dir`
+-- so it works from a normal checkout or a git worktree.
+return {
+  "coder/claudecode.nvim",
+  dir = vim.g.claudecode_dev_dir,
+  dependencies = { "folke/snacks.nvim" },
+  keys = {
+    { "<leader>a", nil, desc = "AI/Claude Code" },
+    { "<leader>ac", "<cmd>ClaudeCode<cr>", desc = "Toggle Claude" },
+    { "<leader>af", "<cmd>ClaudeCodeFocus<cr>", desc = "Focus Claude" },
+    { "<leader>aS", "<cmd>ClaudeCodeStart<cr>", desc = "Start Claude Server" },
+    { "<leader>aQ", "<cmd>ClaudeCodeStop<cr>", desc = "Stop Claude Server" },
+    -- Built-in command path: focus the picker LIST window, then run this.
+    { "<leader>at", "<cmd>ClaudeCodeTreeAdd<cr>", desc = "Tree/Picker Add" },
+  },
+  ---@type PartialClaudeCodeConfig
+  opts = {
+    -- Keep behavior predictable for reproduction; start the server explicitly.
+    log_level = "debug",
+  },
+}

fixtures/snacks-picker/lua/plugins/init.lua

@@ -0,0 +1,11 @@
+-- Basic plugin configuration
+return {
+  {
+    "folke/tokyonight.nvim",
+    lazy = false,
+    priority = 1000,
+    config = function()
+      vim.cmd([[colorscheme tokyonight]])
+    end,
+  },
+}

fixtures/snacks-picker/lua/plugins/snacks.lua

@@ -0,0 +1,75 @@
+-- snacks.nvim picker fixture for issue #192.
+--
+-- Demonstrates BOTH integration paths for adding a picker's selected/highlighted
+-- file(s) to Claude Code's context:
+--
+--   1. WORKAROUND (works TODAY, no claudecode.nvim change): a custom snacks picker
+--      `action` (`claude_add`) bound to <c-o> in the input AND list windows. This
+--      is the idiomatic snacks way and works from the input box in insert mode.
+--      It mirrors how the community claude-fzf.nvim plugin integrates fzf-lua.
+--
+--   2. Built-in command path: `:ClaudeCodeTreeAdd` also works when the picker
+--      LIST window is focused (vim.bo.filetype == "snacks_picker_list"), via the
+--      in-core snacks_picker_list handler in lua/claudecode/integrations.lua.
+return {
+  "folke/snacks.nvim",
+  priority = 1000,
+  lazy = false,
+  ---@type snacks.Config
+  opts = {
+    picker = {
+      enabled = true,
+      ---@type table<string, snacks.picker.Action.spec>
+      actions = {
+        -- WORKAROUND action: send the selected (Tab) items, or the item under
+        -- the cursor when nothing is selected, to Claude as @-mentions.
+        claude_add = function(picker)
+          local items = picker:selected({ fallback = true })
+          local claudecode = require("claudecode")
+          local count = 0
+          for _, item in ipairs(items) do
+            local path = Snacks.picker.util.path(item)
+            if path and path ~= "" then
+              local ok = claudecode.send_at_mention(path, nil, nil, "snacks-picker")
+              if ok then
+                count = count + 1
+              end
+            end
+          end
+          picker:close()
+          vim.schedule(function()
+            vim.notify(("[claude_add] Added %d file(s) to Claude context"):format(count), vim.log.levels.INFO)
+          end)
+        end,
+      },
+      win = {
+        input = {
+          keys = {
+            ["<c-o>"] = { "claude_add", mode = { "i", "n" }, desc = "Add to Claude Code" },
+          },
+        },
+        list = {
+          keys = {
+            ["<c-o>"] = { "claude_add", desc = "Add to Claude Code" },
+          },
+        },
+      },
+    },
+  },
+  keys = {
+    {
+      "<leader>ff",
+      function()
+        Snacks.picker.files()
+      end,
+      desc = "Find Files (snacks picker)",
+    },
+    {
+      "<leader>fg",
+      function()
+        Snacks.picker.grep()
+      end,
+      desc = "Grep (snacks picker)",
+    },
+  },
+}