feat: add env configuration option

- Add env field to config for passing environment variables to Claude CLI
- Update init.lua to pass env variables when spawning Claude terminal
- Allows users to set custom environment like ANTHROPIC_API_KEY

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: totalolage

lua/claudecode/config.lua

@@ -6,6 +6,7 @@ M.defaults = {
   port_range = { min = 10000, max = 65535 },
   auto_start = true,
   terminal_cmd = nil,
+  env = {}, -- Custom environment variables for Claude terminal
   log_level = "info",
   track_selection = true,
   visual_demotion_delay_ms = 50, -- Milliseconds to wait before demoting a visual selection
@@ -74,6 +75,13 @@ function M.validate(config)
   assert(type(config.diff_opts.vertical_split) == "boolean", "diff_opts.vertical_split must be a boolean")
   assert(type(config.diff_opts.open_in_current_tab) == "boolean", "diff_opts.open_in_current_tab must be a boolean")
 
+  -- Validate env
+  assert(type(config.env) == "table", "env must be a table")
+  for key, value in pairs(config.env) do
+    assert(type(key) == "string", "env keys must be strings")
+    assert(type(value) == "string", "env values must be strings")
+  end
+
   return true
 end
 
@@ -87,6 +95,14 @@ function M.apply(user_config)
     config = vim.tbl_deep_extend("force", config, user_config)
   end
 
+  -- Check environment variable for terminal_cmd if not set in user config
+  if config.terminal_cmd == nil then
+    local env_cmd = vim.fn.getenv("CLAUDE_TERMINAL_CMD")
+    if env_cmd ~= vim.NIL then
+      config.terminal_cmd = env_cmd
+    end
+  end
+
   M.validate(config)
 
   return config

lua/claudecode/init.lua

@@ -36,6 +36,7 @@ M.version = {
 --- @field port_range {min: integer, max: integer} Port range for WebSocket server.
 --- @field auto_start boolean Auto-start WebSocket server on Neovim startup.
 --- @field terminal_cmd string|nil Custom terminal command to use when launching Claude.
+--- @field env table<string,string> Custom environment variables for Claude terminal.
 --- @field log_level "trace"|"debug"|"info"|"warn"|"error" Log level.
 --- @field track_selection boolean Enable sending selection updates to Claude.
 --- @field visual_demotion_delay_ms number Milliseconds to wait before demoting a visual selection.
@@ -49,6 +50,7 @@ local default_config = {
   port_range = { min = 10000, max = 65535 },
   auto_start = true,
   terminal_cmd = nil,
+  env = {},
   log_level = "info",
   track_selection = true,
   visual_demotion_delay_ms = 50, -- Reduced from 200ms for better responsiveness in tree navigation
@@ -303,14 +305,14 @@ function M.setup(opts)
 
   logger.setup(M.state.config)
 
-  -- Setup terminal module: always try to call setup to pass terminal_cmd,
+  -- Setup terminal module: always try to call setup to pass terminal_cmd and env,
   -- even if terminal_opts (for split_side etc.) are not provided.
   local terminal_setup_ok, terminal_module = pcall(require, "claudecode.terminal")
   if terminal_setup_ok then
     -- Guard in case tests or user replace the module with a minimal stub without `setup`.
     if type(terminal_module.setup) == "function" then
       -- terminal_opts might be nil, which the setup function should handle gracefully.
-      terminal_module.setup(terminal_opts, M.state.config.terminal_cmd)
+      terminal_module.setup(terminal_opts, M.state.config.terminal_cmd, M.state.config.env)
     end
   else
     logger.error("init", "Failed to load claudecode.terminal module for setup.")

lua/claudecode/terminal.lua

@@ -24,6 +24,7 @@ local config = {
   show_native_term_exit_tip = true,
   terminal_cmd = nil,
   auto_close = true,
+  env = {}, -- Custom environment variables for Claude terminal
 }
 
 -- Lazy load providers
@@ -148,6 +149,11 @@ local function get_claude_command_and_env(cmd_args)
     env_table["CLAUDE_CODE_SSE_PORT"] = tostring(sse_port_value)
   end
 
+  -- Merge custom environment variables from config
+  for key, value in pairs(config.env) do
+    env_table[key] = value
+  end
+
   return cmd_string, env_table
 end
 
@@ -180,7 +186,8 @@ end
 -- @field user_term_config.provider string 'snacks' or 'native' (default: 'snacks').
 -- @field user_term_config.show_native_term_exit_tip boolean Show tip for exiting native terminal (default: true).
 -- @param p_terminal_cmd string|nil The command to run in the terminal (from main config).
-function M.setup(user_term_config, p_terminal_cmd)
+-- @param p_env table|nil Custom environment variables to pass to the terminal (from main config).
+function M.setup(user_term_config, p_terminal_cmd, p_env)
   if user_term_config == nil then -- Allow nil, default to empty table silently
     user_term_config = {}
   elseif type(user_term_config) ~= "table" then -- Warn if it's not nil AND not a table
@@ -198,6 +205,16 @@ function M.setup(user_term_config, p_terminal_cmd)
     config.terminal_cmd = nil -- Fallback to default behavior
   end
 
+  if p_env == nil or type(p_env) == "table" then
+    config.env = p_env or {}
+  else
+    vim.notify(
+      "claudecode.terminal.setup: Invalid env provided: " .. tostring(p_env) .. ". Using empty table.",
+      vim.log.levels.WARN
+    )
+    config.env = {}
+  end
+
   for k, v in pairs(user_term_config) do
     if config[k] ~= nil and k ~= "terminal_cmd" then -- terminal_cmd is handled above
       if k == "split_side" and (v == "left" or v == "right") then