diff --git a/docs/manual/release-notes/rl-0.9.md b/docs/manual/release-notes/rl-0.9.md
index 1c9bab61..90d28e53 100644
--- a/docs/manual/release-notes/rl-0.9.md
+++ b/docs/manual/release-notes/rl-0.9.md
@@ -176,6 +176,10 @@
 
 - Added [`golangci-lint`](https://golangci-lint.run/) for more diagnostics.
 
+- updated default filetypes for
+  [harper-ls](https://github.com/Automattic/harper) to match what they are
+  supposed to be.
+
 - Added Makefile support via `languages.make`.
 
 - Added Debugging support to `languages.php`.
diff --git a/modules/plugins/lsp/harper-ls/config.nix b/modules/plugins/lsp/harper-ls/config.nix
index d6e27bfc..41a51c62 100644
--- a/modules/plugins/lsp/harper-ls/config.nix
+++ b/modules/plugins/lsp/harper-ls/config.nix
@@ -11,9 +11,47 @@
 in {
   config = mkIf (cfg.enable && cfg.harper-ls.enable) {
     vim.lsp.servers.harper-ls = {
-      root_markers = [".git"];
+      root_markers = [".git" ".harper-dictionary.txt"];
       cmd = [(getExe pkgs.harper) "--stdio"];
       settings = {harper-ls = cfg.harper-ls.settings;};
+      filetypes =
+        # <https://writewithharper.com/docs/integrations/language-server#Supported-Languages>
+        [
+          "asciidoc"
+          "c"
+          "clojure"
+          "cmake"
+          "cpp"
+          "cs"
+          "daml"
+          "dart"
+          "gitcommit"
+          "go"
+          "haskell"
+          "html"
+          "ink"
+          "java"
+          "javascript"
+          "javascriptreact"
+          "kotlin"
+          "lhaskell"
+          "lua"
+          "mail"
+          "markdown"
+          "nix"
+          "php"
+          "python"
+          "ruby"
+          "rust"
+          "scala"
+          "sh"
+          "swift"
+          "text"
+          "toml"
+          "typescript"
+          "typescriptreact"
+          "typst"
+        ];
     };
   };
 }