diff --git a/.tangled/workflows/ci.yml b/.tangled/workflows/ci.yml
index 2131b5a..45d5251 100644
--- a/.tangled/workflows/ci.yml
+++ b/.tangled/workflows/ci.yml
@@ -36,7 +36,8 @@ steps:
   # Install the Elixir toolchain into the workspace and pre-compile, so the
   # later steps are quiet and just run their one check. The workspace (incl.
   # .elixir, deps/, _build/) persists across steps; PATH does not, so each
-  # Elixir step re-exports it.
+  # Elixir step re-exports it. The compile is run with --warnings-as-errors so
+  # any compiler warning fails the build here rather than slipping through.
   - name: "Setup (toolchain + deps)"
     command: |
       set -eu
@@ -59,7 +60,7 @@ steps:
       mix local.hex --force
       mix local.rebar --force
       mix deps.get
-      mix compile
+      mix compile --warnings-as-errors
 
   - name: "Format"
     command: |
diff --git a/CLAUDE.md b/CLAUDE.md
index f0c4f46..b3a32c2 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -27,8 +27,11 @@ mise run setup                        # install tools, deps, wire git hooks (hk)
 ```
 
 `hk` runs a pre-commit hook: `mix format --check-formatted` on staged `.ex/.exs`,
-`tsc --noEmit` when staged `.ts` files exist, and `shadix-registry` (regenerate +
-re-stage `priv/registry/*.json`) when a component source or `assets/ts/*.ts` is staged.
+`mix compile --warnings-as-errors` when staged `.ex/.exs` exists (compiler warnings
+block the commit), `tsc --noEmit` when staged `.ts` files exist, and `shadix-registry`
+(regenerate + re-stage `priv/registry/*.json`) when a component source or
+`assets/ts/*.ts` is staged. CI mirrors this: the setup step compiles with
+`--warnings-as-errors`, so warnings fail the build.
 
 A11y tests are a **separate** Playwright/axe-core suite under `test/a11y/` (its own
 `package.json`, not run by `mix test`). They drive the live docs site.
diff --git a/hk.pkl b/hk.pkl
index faef573..9e0b780 100644
--- a/hk.pkl
+++ b/hk.pkl
@@ -6,6 +6,15 @@ local linters = new Mapping<String, Step> {
         check = "mix format --check-formatted {{files}}"
         fix = "mix format {{files}}"
     }
+    // Compile with --warnings-as-errors so compiler warnings block the commit.
+    // Gated on staged Elixir sources (mirrors mix-format) so it stays dormant
+    // for non-code changes; no glob would make it run on every commit. It's a
+    // check-only step (compile can't auto-fix), so it runs in both `hk check`
+    // and the `fix = true` pre-commit hook.
+    ["mix-compile"] {
+        glob = List("*.ex", "*.exs")
+        check = "mix compile --warnings-as-errors"
+    }
     // Whole-project type check; gated on staged .ts files so it stays dormant
     // until the TypeScript hooks land under assets/.
     ["tsc"] {
diff --git a/website/components/component_doc.ex b/website/components/component_doc.ex
index 6c6c6a4..4d2e2e0 100644
--- a/website/components/component_doc.ex
+++ b/website/components/component_doc.ex
@@ -49,14 +49,12 @@ defmodule Shadix.Website.Components.ComponentDoc do
     end
 
     compiled =
-      EEx.compile_string(source,
-        engine: Phoenix.LiveView.TagEngine,
-        tag_handler: Phoenix.LiveView.HTMLEngine,
+      Phoenix.LiveView.TagEngine.compile(source,
         caller: __CALLER__,
-        source: source,
         file: __CALLER__.file,
         line: __CALLER__.line,
-        indentation: 0
+        indentation: 0,
+        tag_handler: Phoenix.LiveView.HTMLEngine
       )
 
     trimmed_source = String.trim_trailing(source)