diff --git a/lua/opencode/provider/snacks.lua b/lua/opencode/provider/snacks.lua
index 683ba5a5..de5c10c1 100644
--- a/lua/opencode/provider/snacks.lua
+++ b/lua/opencode/provider/snacks.lua
@@ -4,6 +4,7 @@
 ---@class opencode.provider.Snacks : opencode.Provider
 ---
 ---@field opts snacks.terminal.Opts
+---@field private _pid number|nil
 local Snacks = {}
 Snacks.__index = Snacks
 Snacks.name = "snacks"
@@ -15,6 +16,30 @@ Snacks.name = "snacks"
 function Snacks.new(opts)
   local self = setmetatable({}, Snacks)
   self.opts = opts or {}
+  self._pid = nil
+
+  -- Hook into on_buf to capture the terminal job's PID when the buffer is created.
+  -- We must capture the PID eagerly at startup because by the time VimLeavePre fires
+  -- and stop() is called, the terminal job has been cleared and terminal_job_id is no
+  -- longer available. This also ensures PID capture happens automatically regardless
+  -- of how the terminal is started (toggle, open), without duplicating the logic.
+  self.opts.win = self.opts.win or {}
+  local user_on_buf = self.opts.win.on_buf
+  self.opts.win.on_buf = function(win)
+    if user_on_buf then
+      user_on_buf(win)
+    end
+    ---@diagnostic disable: invisible -- accessing private fields from closure within constructor
+    vim.api.nvim_create_autocmd("TermOpen", {
+      buffer = win.buf,
+      once = true,
+      callback = function()
+        self:get_pid()
+      end,
+    })
+    ---@diagnostic enable: invisible
+  end
+
   return self
 end
 
@@ -54,12 +79,30 @@ function Snacks:start()
 end
 
 function Snacks:stop()
+  require("opencode.provider.util").kill(self:get_pid())
+  self._pid = nil
+
   local win = self:get()
   if win then
-    -- TODO: Stop the job first so we don't get error exit code.
-    -- Not sure how to get the job ID from snacks API though.
     win:close()
   end
 end
 
+---Capture and cache the PID of the terminal job.
+---@return number?
+function Snacks:get_pid()
+  local buf = self:get() and self:get().buf
+  if not self._pid and buf then
+    local job_id = vim.b[buf].terminal_job_id
+    if job_id then
+      local ok, pid = pcall(vim.fn.jobpid, job_id)
+      if ok then
+        self._pid = pid
+      end
+    end
+  end
+
+  return self._pid
+end
+
 return Snacks
diff --git a/lua/opencode/provider/terminal.lua b/lua/opencode/provider/terminal.lua
index 8b1b61c6..e7a3cbf7 100644
--- a/lua/opencode/provider/terminal.lua
+++ b/lua/opencode/provider/terminal.lua
@@ -5,6 +5,7 @@
 ---
 ---@field bufnr? integer
 ---@field winid? integer
+---@field private _pid number|nil
 local Terminal = {}
 Terminal.__index = Terminal
 Terminal.name = "terminal"
@@ -16,6 +17,7 @@ function Terminal.new(opts)
   self.opts = opts or {}
   self.winid = nil
   self.bufnr = nil
+  self._pid = nil
   return self
 end
 
@@ -71,12 +73,17 @@ function Terminal:start()
       once = true,
       callback = function(event)
         require("opencode.keymaps").apply(event.buf)
+        -- Cache PID eagerly at terminal open time because by the time VimLeavePre fires
+        -- and stop() is called, the terminal job has been cleared and terminal_job_id
+        -- is no longer available.
+        self:get_pid()
       end,
     })
 
     vim.fn.jobstart(self.cmd, {
       term = true,
       on_exit = function()
+        self._pid = nil
         self.winid = nil
         self.bufnr = nil
       end,
@@ -86,15 +93,40 @@ function Terminal:start()
   end
 end
 
----Close the window, delete the buffer.
 function Terminal:stop()
+  local job_id = vim.b[self.bufnr].terminal_job_id
+  if job_id then
+    -- Apparently we still have to do this ourselves when Neovim *isn't* stopping.
+    -- Not needed for snacks.terminal - I guess it does it internally?
+    vim.fn.jobstop(job_id)
+  end
+  require("opencode.provider.util").kill(self:get_pid())
+  self._pid = nil
+
   if self.winid ~= nil and vim.api.nvim_win_is_valid(self.winid) then
     vim.api.nvim_win_close(self.winid, true)
     self.winid = nil
   end
   if self.bufnr ~= nil and vim.api.nvim_buf_is_valid(self.bufnr) then
     vim.api.nvim_buf_delete(self.bufnr, { force = true })
+    self.bufnr = nil
   end
 end
 
+---Capture and cache the PID of the terminal job.
+---@return number?
+function Terminal:get_pid()
+  if not self._pid and self.bufnr then
+    local job_id = vim.b[self.bufnr].terminal_job_id
+    if job_id then
+      local ok, pid = pcall(vim.fn.jobpid, job_id)
+      if ok then
+        self._pid = pid
+      end
+    end
+  end
+
+  return self._pid
+end
+
 return Terminal
diff --git a/lua/opencode/provider/tmux.lua b/lua/opencode/provider/tmux.lua
index 747217c1..dcd88799 100644
--- a/lua/opencode/provider/tmux.lua
+++ b/lua/opencode/provider/tmux.lua
@@ -99,6 +99,7 @@ function Tmux:start()
         string.format("tmux split-window %s -P -F '#{pane_id}' %s '%s'", detach_flag, self.opts.options or "", self.cmd)
       )
     )
+
     local disable_passthrough = self.opts.allow_passthrough ~= true -- default true (disable passthrough)
     if disable_passthrough and self.pane_id and self.pane_id ~= "" then
       vim.fn.system(string.format("tmux set-option -t %s -p allow-passthrough off", self.pane_id))
@@ -108,12 +109,20 @@ end
 
 ---Kill the `opencode` pane.
 function Tmux:stop()
-  local pane_id = self:get_pane_id()
-  if pane_id then
-    -- HACK: https://github.com/nickjvandyke/opencode.nvim/issues/118
-    vim.fn.system("tmux send-keys -t " .. pane_id .. " C-c")
-    self.pane_id = nil
+  local pid = self:get_pid()
+  if pid then
+    require("opencode.provider.util").kill(pid)
   end
 end
 
+---Capture the PID of the process running in the pane.
+---@return number?
+function Tmux:get_pid()
+  if not self.pane_id then
+    return nil
+  end
+
+  return tonumber(vim.trim(vim.fn.system("tmux display-message -p -t " .. self.pane_id .. " '#{pane_pid}'")))
+end
+
 return Tmux
diff --git a/lua/opencode/provider/util.lua b/lua/opencode/provider/util.lua
new file mode 100644
index 00000000..f825cbf8
--- /dev/null
+++ b/lua/opencode/provider/util.lua
@@ -0,0 +1,25 @@
+local M = {}
+
+---Terminate the process and its children reliably.
+---HACK: for upstream issue described in https://github.com/anomalyco/opencode/issues/13001.
+---
+---Uses the cached PID to kill the entire process group, which is more reliable
+---than jobstop during VimLeavePre because:
+--- 1. os.execute is synchronous (vim.fn.system spawns a job that Neovim kills during shutdown)
+--- 2. Negative PID sends SIGTERM to the entire process group (children included)
+--- 3. jobstop sends SIGHUP which can cause the process to daemonize/respawn
+---@param pid number|nil The cached process ID
+---@return boolean killed Whether the process was successfully terminated
+function M.kill(pid)
+  if not pid then
+    return false
+  end
+
+  if vim.fn.has("unix") == 1 then
+    return os.execute("kill -TERM -" .. pid .. " 2>/dev/null") ~= nil
+  else
+    return pcall(vim.uv.kill, pid, "sigterm")
+  end
+end
+
+return M