diff --git a/get-shit-done/bin/lib/state.cjs b/get-shit-done/bin/lib/state.cjs
index dd3845c3b..d93f2e2ac 100644
--- a/get-shit-done/bin/lib/state.cjs
+++ b/get-shit-done/bin/lib/state.cjs
@@ -733,9 +733,20 @@ function stripFrontmatter(content) {
 }
 
 function syncStateFrontmatter(content, cwd) {
+  // Read existing frontmatter BEFORE stripping — it may contain values
+  // that the body no longer has (e.g., Status field removed by an agent).
+  const existingFm = extractFrontmatter(content);
   const body = stripFrontmatter(content);
-  const fm = buildStateFrontmatter(body, cwd);
-  const yamlStr = reconstructFrontmatter(fm);
+  const derivedFm = buildStateFrontmatter(body, cwd);
+
+  // Preserve existing frontmatter status when body-derived status is 'unknown'.
+  // This prevents a missing Status: field in the body from overwriting a
+  // previously valid status (e.g., 'executing' → 'unknown').
+  if (derivedFm.status === 'unknown' && existingFm.status && existingFm.status !== 'unknown') {
+    derivedFm.status = existingFm.status;
+  }
+
+  const yamlStr = reconstructFrontmatter(derivedFm);
   return `---\n${yamlStr}\n---\n\n${body}`;
 }
 
diff --git a/tests/state.test.cjs b/tests/state.test.cjs
index 7f86f25fc..82023c347 100644
--- a/tests/state.test.cjs
+++ b/tests/state.test.cjs
@@ -475,6 +475,30 @@ describe('STATE.md frontmatter sync', () => {
     assert.ok(content.includes('status: paused'), 'frontmatter should reflect latest status');
   });
 
+  test('preserves frontmatter status when body Status field is missing', () => {
+    // Simulate: frontmatter has status: executing, but body lost Status: field
+    fs.writeFileSync(
+      path.join(tmpDir, '.planning', 'STATE.md'),
+      `---
+status: executing
+milestone: v1.0
+---
+
+# Project State
+
+**Current Phase:** 03
+**Current Plan:** 03-02
+`
+    );
+
+    // Any writeStateMd triggers syncStateFrontmatter — use state update on a field that exists
+    runGsdTools('state update "Current Plan" "03-03"', tmpDir);
+
+    const content = fs.readFileSync(path.join(tmpDir, '.planning', 'STATE.md'), 'utf-8');
+    assert.ok(content.includes('status: executing'), 'should preserve existing status, not overwrite with unknown');
+    assert.ok(!content.includes('status: unknown'), 'should not contain unknown status');
+  });
+
   test('round-trip: write then read via state json', () => {
     fs.writeFileSync(
       path.join(tmpDir, '.planning', 'STATE.md'),