diff --git a/CONTEXT.md b/CONTEXT.md
index 95c20b236..544919edd 100644
--- a/CONTEXT.md
+++ b/CONTEXT.md
@@ -722,6 +722,14 @@ A legal deferred state of an Execute step (`external_job_waiting`): the executor
 `DEFECT.WINDOWS-TEST-PORTABILITY.fix-forward=gate platform-specific execution with if (process.platform !== 'win32'); normalize path expectations to forward slashes with .replace(/\\/g, '/'); invoke scripts via explicit interpreter (sh <path>) rather than relying on exec-bit; annotate // windows-portability-ok: <reason> when a bypass is intentional`
 `DEFECT.WINDOWS-TEST-PORTABILITY.prevention=run lint:ci before opening a PR; treat the CI windows lane as the only true Windows signal — gsd-test (Mac/Linux only) cannot substitute for it`
 
+`DEFECT.WINDOWS-PATH-LEAK-IN-MARKDOWN-CONTENT.symptom=path.join() result on Windows (backslashes) substituted verbatim into markdown body (@-references, workflow files, generated docs); content gains mixed separators; cross-platform substring assertions fail on windows-latest CI lane only; macOS/Linux CI green so defect ships undetected`
+`DEFECT.WINDOWS-PATH-LEAK-IN-MARKDOWN-CONTENT.examples=PR #1622 computePathPrefix returned ${resolvedTarget}/ verbatim — rewrites of @~/.claude/gsd-core/commands/gsd/X.md wrote @C:\...\gsd-ial-windsurf-XXX\gsd-core/commands/gsd/help.md (trailing forward slashes from the original literal survived, prefix backslashes did not); tests/install-runtime-artifacts.test.cjs:318 + tests/install.test.cjs:1323 failed on windows-latest only`
+`DEFECT.WINDOWS-PATH-LEAK-IN-MARKDOWN-CONTENT.detect=any function returning a filesystem path that flows into markdown/text body substitution; grep for path.join/raw resolvedTarget/${configDir}/ in code paths writing workflow .md, agent .md, or generated docs; smoke pattern is ${resolvedTarget}/ or ${configDir}/... templates that bypass normalization`
+`DEFECT.WINDOWS-PATH-LEAK-IN-MARKDOWN-CONTENT.fix-forward=normalize at the SOURCE not the test: posixTarget=String(resolvedTarget).replace(/\\/g,'/'), posixHome=homeDir?String(homeDir).replace(/\\/g,'/'):homeDir; markdown body is POSIX-only; .replace(/\\/g,'/') is idempotent on POSIX (no backslashes present) so safe to apply unconditionally; isWindowsHost arg is a no-op tripwire (enh-1511) — do NOT branch on it, normalize always`
+`DEFECT.WINDOWS-PATH-LEAK-IN-MARKDOWN-CONTENT.prevention=RULESET.CONTENT-PATH-NORMALIZATION; tests are downstream signal, never the fix; ref DEFECT.WINDOWS-TEST-PORTABILITY for test-side parity (normalize expected substrings too: ${configDir}/foo.replace(/\\/g,'/'))`
+
+`RULESET.CONTENT-PATH-NORMALIZATION=filesystem paths substituted into markdown body text (@-references, workflow .md, agent .md, generated docs, command bodies) MUST be normalized to POSIX forward slashes via .replace(/\\/g,'/') at the production source BEFORE substitution; never push normalization to tests; cross-platform content is POSIX-only; applies to: computePathPrefix output, install-path rewrites, generated shim paths emitted into .md bodies; idempotent on POSIX so unconditional`
+
 
 ---
 
diff --git a/src/runtime-artifact-conversion.cts b/src/runtime-artifact-conversion.cts
index 7f8f48d10..1f244cf5e 100644
--- a/src/runtime-artifact-conversion.cts
+++ b/src/runtime-artifact-conversion.cts
@@ -2169,10 +2169,18 @@ function convertClaudeCommandToKiloSkill(content, skillName) {
  * @private — exported as `_computePathPrefix` for tests.
  */
 function computePathPrefix({ isGlobal, isOpencode, isWindowsHost: _isWindowsHost, resolvedTarget, homeDir }) {
-  if (isGlobal && resolvedTarget.startsWith(homeDir) && !isOpencode) {
-    return '$HOME' + resolvedTarget.slice(homeDir.length) + '/';
+  // #1615: normalize Windows backslashes to forward slashes. This prefix is
+  // substituted into markdown @-references (e.g. Windsurf workflow files),
+  // which use POSIX paths universally. Idempotent on POSIX (no backslashes).
+  // Without this, path.join on Windows produces a backslash prefix that
+  // leaks into markdown content and breaks cross-platform substring checks.
+  // See DEFECT.WINDOWS-PATH-LEAK-IN-MARKDOWN-CONTENT in CONTEXT.md.
+  const posixTarget = String(resolvedTarget).replace(/\\/g, '/');
+  const posixHome = homeDir ? String(homeDir).replace(/\\/g, '/') : homeDir;
+  if (isGlobal && posixTarget.startsWith(posixHome) && !isOpencode) {
+    return '$HOME' + posixTarget.slice(posixHome.length) + '/';
   }
-  return `${resolvedTarget}/`;
+  return `${posixTarget}/`;
 }
 
 /**
diff --git a/tests/enh-1511-rewrite-engine-relocation.test.cjs b/tests/enh-1511-rewrite-engine-relocation.test.cjs
index 6321ed053..949e7c2b9 100644
--- a/tests/enh-1511-rewrite-engine-relocation.test.cjs
+++ b/tests/enh-1511-rewrite-engine-relocation.test.cjs
@@ -91,6 +91,22 @@ describe('_computePathPrefix', () => {
     assert.equal(withWindows, '$HOME/.cursor/');
     assert.strictEqual(withWindows, withoutWindows);
   });
+
+  test('backslash-style resolvedTarget is normalized to forward slashes (#1615 regression)', () => {
+    // path.join on Windows produces backslashes; the returned prefix is
+    // substituted into markdown @-references which must use POSIX paths.
+    // Without normalization the backslashes leak into workflow file content
+    // and break substring checks on Windows CI.
+    const prefix = conversion._computePathPrefix({
+      isGlobal: false,
+      isOpencode: false,
+      isWindowsHost: true,
+      resolvedTarget: 'C:\\Users\\runner\\AppData\\Local\\Temp\\gsd-1615-windsurf',
+      homeDir: 'C:\\Users\\runner',
+    });
+    assert.strictEqual(prefix, 'C:/Users/runner/AppData/Local/Temp/gsd-1615-windsurf/');
+    assert.ok(!prefix.includes('\\'), `prefix must not contain backslashes: ${prefix}`);
+  });
 });
 
 // ---------------------------------------------------------------------------
diff --git a/tests/install-runtime-artifacts.test.cjs b/tests/install-runtime-artifacts.test.cjs
index 863305e57..0132978d8 100644
--- a/tests/install-runtime-artifacts.test.cjs
+++ b/tests/install-runtime-artifacts.test.cjs
@@ -315,7 +315,7 @@ describe('installRuntimeArtifacts — windsurf workflows layout (#1615)', () =>
     const helpContent = fs.readFileSync(path.join(workflowsDir, 'gsd-help.md'), 'utf8');
     assert.ok(!helpContent.startsWith('---'), 'Windsurf workflows must be plain markdown, not SKILL.md frontmatter');
     assert.match(helpContent, /# gsd-help/, 'workflow should identify the slash command it backs');
-    assert.ok(helpContent.includes(`${configDir}/gsd-core/commands/gsd/help.md`),
+    assert.ok(helpContent.includes(`${configDir}/gsd-core/commands/gsd/help.md`.replace(/\\/g, '/')),
       'workflow should reference the installed command body using the actual install target');
 
     for (const fileName of fs.readdirSync(workflowsDir)) {
diff --git a/tests/install.test.cjs b/tests/install.test.cjs
index db2cb94ee..22ab9e9d6 100644
--- a/tests/install.test.cjs
+++ b/tests/install.test.cjs
@@ -1320,7 +1320,7 @@ describe('windsurf local install writes workflow slash commands (#1615)', () =>
       const workflowFile = path.join(workflowsDir, workflowEntry.name);
       const content = fs.readFileSync(workflowFile, 'utf8');
       assert.ok(
-        content.includes(`${tmpDir}/.windsurf/gsd-core/commands/gsd/`),
+        content.includes(`${tmpDir}/.windsurf/gsd-core/commands/gsd/`.replace(/\\/g, '/')),
         `${workflowEntry.name} must reference the installed canonical command body`,
       );
       assert.ok(