diff --git a/Makefile b/Makefile
index 3fd83fe..2a8ebbc 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-all: fmt apply
+all: fmt apply nvim-check
 
 apply:
 	uv run ansible-playbook -i ~/.dotfiles/ansible/inventory.ini ~/.dotfiles/ansible/dotfiles.yml
@@ -13,3 +13,33 @@ fmt_check:
 
 nvim-health:
 	nvim --headless "+checkhealth" +qa
+
+# Smoke test: boot nvim with representative filetypes and fail on startup errors/warnings.
+# Catches plugin misconfigurations (e.g. missing tree-sitter parsers, broken submodules)
+# that produce warnings in :messages but pass :checkhealth.
+NVIM_CHECK_FILETYPES := R py lua md
+NVIM_CHECK_TMPDIR := /tmp/_nvim_check
+NVIM_CHECK_TIMEOUT := 30
+
+nvim-check:
+	@mkdir -p $(NVIM_CHECK_TMPDIR)
+	@fail=0; \
+	for ft in $(NVIM_CHECK_FILETYPES); do \
+	  tmpfile="$(NVIM_CHECK_TMPDIR)/test.$$ft"; \
+	  msgfile="$(NVIM_CHECK_TMPDIR)/messages_$$ft.txt"; \
+	  touch "$$tmpfile"; \
+	  timeout $(NVIM_CHECK_TIMEOUT) nvim --headless \
+	    +"edit $$tmpfile" \
+	    +"sleep 3" \
+	    +"redir! > $$msgfile | silent messages | redir END" \
+	    +"qall!" 2>/dev/null || true; \
+	  if grep -qiE '(error|warning)' "$$msgfile" 2>/dev/null; then \
+	    echo "FAIL [$$ft]: startup errors detected"; \
+	    cat "$$msgfile"; \
+	    fail=1; \
+	  else \
+	    echo "PASS [$$ft]: clean startup"; \
+	  fi; \
+	done; \
+	rm -rf $(NVIM_CHECK_TMPDIR); \
+	[ "$$fail" -eq 0 ] || (echo "nvim-check: some filetypes had errors" && exit 1)
diff --git a/ansible/tasks/neovim.yml b/ansible/tasks/neovim.yml
index 76f91ae..9f80556 100644
--- a/ansible/tasks/neovim.yml
+++ b/ansible/tasks/neovim.yml
@@ -46,3 +46,16 @@
       - "+qa"
   tags:
     - nvim
+
+- name: Clone tree-sitter-rout parser source into R.nvim resources
+  # TODO: Remove once https://github.com/R-nvim/R.nvim/issues/466 is fixed and merged -- see
+  # nvim/lua/plugins/language.lua for full context. Idempotent: skipped if grammar.js exists.
+  ansible.builtin.shell: |
+    target="{{ ansible_env.HOME }}/.local/share/nvim/lazy/R.nvim/resources/tree-sitter-rout"
+    grammar="$target/grammar.js"
+    if [ ! -f "$grammar" ]; then
+      rm -rf "$target"
+      git clone https://github.com/R-nvim/tree-sitter-rout "$target"
+    fi
+  tags:
+    - nvim
diff --git a/nvim/lua/plugins/language.lua b/nvim/lua/plugins/language.lua
index ae5841a..9df596b 100644
--- a/nvim/lua/plugins/language.lua
+++ b/nvim/lua/plugins/language.lua
@@ -1,4 +1,22 @@
 return {
+  {
+    "R-nvim/R.nvim",
+    -- TODO: Remove this build workaround once https://github.com/R-nvim/R.nvim/issues/466 is
+    -- fixed and merged to main, then advance past that commit with `:Lazy update R.nvim`.
+    -- The upstream bug: check_rout_parser() calls vim.uv.chdir() into resources/tree-sitter-rout
+    -- but early `return` on build failure skips the chdir(cwdir) restore, leaving nvim stuck in
+    -- the plugin directory. Root cause is that the tree-sitter-rout submodule gitlink is absent
+    -- from older pinned commits, so `git submodule update` is a no-op and grammar.js is missing.
+    -- Workaround: clone the source directly so the build succeeds and cwd is properly restored.
+    -- Removal check: delete this block, run `make nvim-check`, confirm PASS [R]: clean startup.
+    build = function()
+      local target = vim.fn.stdpath("data") .. "/lazy/R.nvim/resources/tree-sitter-rout"
+      if vim.fn.filereadable(target .. "/grammar.js") == 0 then
+        vim.fn.system({ "rm", "-rf", target })
+        vim.fn.system({ "git", "clone", "https://github.com/R-nvim/tree-sitter-rout", target })
+      end
+    end,
+  },
   {
     "nvim-treesitter/nvim-treesitter",
     opts = {