diff --git a/scripts/hooks/stop-format-typecheck.js b/scripts/hooks/stop-format-typecheck.js
index 8ae580db5..bfca2fcd2 100644
--- a/scripts/hooks/stop-format-typecheck.js
+++ b/scripts/hooks/stop-format-typecheck.js
@@ -111,6 +111,14 @@ function findTsConfigDir(filePath) {
   return null;
 }
 
+function diagnosticMatchesFile(line, paths) {
+  const normalizedLine = line.replace(/\\/g, '/');
+  for (const candidate of paths) {
+    if (normalizedLine.includes(candidate.replace(/\\/g, '/'))) return true;
+  }
+  return false;
+}
+
 function typecheckBatch(tsConfigDir, editedFiles, timeoutMs) {
   const isWin = process.platform === 'win32';
   const npxBin = isWin ? 'npx.cmd' : 'npx';
@@ -147,7 +155,7 @@ function typecheckBatch(tsConfigDir, editedFiles, timeoutMs) {
     const relPath = path.relative(tsConfigDir, filePath);
     const candidates = new Set([filePath, relPath]);
     const relevantLines = lines
-      .filter(line => { for (const c of candidates) { if (line.includes(c)) return true; } return false; })
+      .filter(line => diagnosticMatchesFile(line, candidates))
       .slice(0, 10);
     if (relevantLines.length > 0) {
       process.stderr.write(`[Hook] TypeScript errors in ${path.basename(filePath)}:\n`);
@@ -248,4 +256,4 @@ if (require.main === module) {
   });
 }
 
-module.exports = { run, parseAccumulator, isPluginClonePath };
+module.exports = { run, parseAccumulator, isPluginClonePath, diagnosticMatchesFile };
diff --git a/tests/hooks/stop-format-typecheck.test.js b/tests/hooks/stop-format-typecheck.test.js
index 564bae693..98c0cfaf7 100644
--- a/tests/hooks/stop-format-typecheck.test.js
+++ b/tests/hooks/stop-format-typecheck.test.js
@@ -13,7 +13,7 @@ const os = require('os');
 const path = require('path');
 
 const accumulator = require('../../scripts/hooks/post-edit-accumulator');
-const { parseAccumulator, isPluginClonePath } = require('../../scripts/hooks/stop-format-typecheck');
+const { parseAccumulator, isPluginClonePath, diagnosticMatchesFile } = require('../../scripts/hooks/stop-format-typecheck');
 
 function test(name, fn) {
   try {
@@ -203,6 +203,12 @@ if (test('parseAccumulator ignores blank lines and trims whitespace', () => {
   assert.deepStrictEqual(result, ['/tmp/a.ts', '/tmp/b.ts']);
 })) passed++; else failed++;
 
+if (test('matches forward-slash TypeScript paths against Windows edited paths', () => {
+  const candidates = new Set(['C:\\project\\src\\broken.ts', 'src\\broken.ts']);
+  assert.strictEqual(diagnosticMatchesFile('src/broken.ts(1,14): error TS2322', candidates), true);
+  assert.strictEqual(diagnosticMatchesFile('src/other.ts(1,14): error TS2322', candidates), false);
+})) passed++; else failed++;
+
 if (test('stop hook clears accumulator after processing duplicates', () => {
   cleanAccumFile();
   fs.writeFileSync(getAccumFile(), '/nonexistent/x.ts\n/nonexistent/x.ts\n/nonexistent/y.ts\n', 'utf8');