diff --git a/CHANGELOG.md b/CHANGELOG.md
index ccef9f2a..5019bba2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -132,6 +132,17 @@ per-file diff commands.
   The standard `date`-first header already worked; regression coverage checks
   all three column orders with and without a BOM.
 
+- **`verify_layout.py` no longer emits a `SyntaxWarning` on every run** (`tools/verify_layout.py`,
+  `tests/test_verify_layout.py`) - the module docstring names the macro whose absence triggers the
+  Poppler `-bbox` crash, `\hypersetup{pdftitle=...}`, and a bare `\h` in a non-raw docstring is an
+  invalid escape sequence. Python 3.12+ prints `SyntaxWarning: "\h" is an invalid escape sequence`
+  the first time the module is compiled (CPython gh-98401) - it shows up in this repo's own CI log,
+  and in the middle of `/apply` Step 5b's layout report. The 3.15 language reference still
+  documents the sequence as a `SyntaxWarning`, with a `SyntaxError` only in a future Python
+  version. Escaped in the docstring; the new `ToolsCompileWithoutWarnings` case compiles the
+  source of every `tools/*.py` with warnings captured and fails on the unescaped version, so the
+  next docstring that quotes a LaTeX macro is caught too.
+
 - **`/apply` Step 5b now actually runs the page-count check it claimed Step 5d ran**
   (`.claude/commands/apply.md`, `tests/test_apply_page_count.py`) - the 5b prose said
   "Page count is not checked here - that is `verify_pdf.py --pages`'s job, and Step 5d already
diff --git a/tests/test_verify_layout.py b/tests/test_verify_layout.py
index 31ce49d9..5483c134 100644
--- a/tests/test_verify_layout.py
+++ b/tests/test_verify_layout.py
@@ -16,6 +16,7 @@ from contextlib import redirect_stdout
 from pathlib import Path
 from unittest.mock import patch
 
+from tools import verify_layout
 from tools.verify_layout import Line, Page, find_orphans, main, parse_pdf, report
 
 A4_HEIGHT = 842.0
@@ -164,5 +165,41 @@ class TestExtractorFailure(unittest.TestCase):
             self.assertIn("skipped:", err.getvalue())
 
 
+class ToolsCompileWithoutWarnings(unittest.TestCase):
+    """Every tool's source must compile clean.
+
+    `verify_layout.py`'s docstring documents LaTeX macros, and a bare `\\h` in a
+    non-raw docstring is an invalid escape sequence: Python 3.12+ emits a
+    SyntaxWarning when the module is compiled (CPython gh-98401), 3.10 and 3.11
+    a DeprecationWarning, so the test records both; the language
+    reference still documents it as a warning in 3.15, with a SyntaxError only
+    in a future Python version. The tool is run per-document from `/apply`, so
+    the warning lands in the middle of a verification report. Compiling is a
+    pure `compile()` over the source text - no cache file, no temp file - so the
+    check costs nothing and covers every `tools/*.py`, guarding the next
+    docstring that quotes a macro too.
+    """
+
+    def test_sources_have_no_invalid_escape_sequences(self):
+        import warnings
+
+        tools_dir = Path(verify_layout.__file__).resolve().parent
+        sources = sorted(tools_dir.glob("*.py"))
+        self.assertIn(Path(verify_layout.__file__).resolve(), sources)
+        offenders: dict[str, list[str]] = {}
+        for source in sources:
+            with warnings.catch_warnings(record=True) as caught:
+                warnings.simplefilter("always")
+                compile(source.read_text(encoding="utf-8"), str(source), "exec")
+            syntax = [
+                str(w.message)
+                for w in caught
+                if issubclass(w.category, (SyntaxWarning, DeprecationWarning))
+            ]
+            if syntax:
+                offenders[source.name] = syntax
+        self.assertEqual({}, offenders, "tools/*.py warn about invalid escapes when compiled")
+
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/tools/verify_layout.py b/tools/verify_layout.py
index b8eb34aa..d43e097c 100644
--- a/tools/verify_layout.py
+++ b/tools/verify_layout.py
@@ -32,7 +32,7 @@ than inventing a layout failure. A broken extractor has two distinct causes: an
 all, and Poppler 26.0x before 26.05 aborts `-bbox`/`-bbox-layout`/`-htmlmeta` on a PDF
 whose Info dictionary carries an empty string in any field - which `hyperref` writes for
 every field it does not set, so any `lualatex`/`pdflatex` document built with `hyperref`
-and no `\hypersetup{pdftitle=...}` triggers a real Poppler crashing on a legal PDF (#451).
+and no `\\hypersetup{pdftitle=...}` triggers a real Poppler crashing on a legal PDF (#451).
 Line height serves
 as a font-size proxy to spot section headings; left edge (xMin) separates bullet lines
 from entry headers.