diff --git a/scripts/evidence.py b/scripts/evidence.py
index afbbd4ca..e630f523 100644
--- a/scripts/evidence.py
+++ b/scripts/evidence.py
@@ -241,7 +241,7 @@ def read_receipt(filename):
     return value
 
 
-def task_context(current=None):
+def task_context(current=None, require_target=True):
     """Verify an existing task checkout; this is not an approval identity."""
     current = snapshot() if current is None else current
     root = Path(git_text("rev-parse", "--show-toplevel")).resolve()
@@ -270,10 +270,11 @@ def task_context(current=None):
     if len(bases) != 1 or bases[0][0] != current["target_branch"] or not GIT_SHA.fullmatch(bases[0][1]):
         raise EvidenceError("Task card has no valid target and initial baseline")
     r0 = bases[0][1]
-    if not current["target_head"]:
+    if not current["target_head"] and require_target:
         raise EvidenceError("Task target is unverified; fetch it first")
     for tip in (current["head"], current["target_head"]):
-        git("merge-base", "--is-ancestor", r0, tip)
+        if tip:
+            git("merge-base", "--is-ancestor", r0, tip)
     check = subprocess.run([sys.executable, str(Path(__file__).with_name("check-worktree.py")), "before-sync"],
                            capture_output=True, text=True)
     if check.returncode:
@@ -301,7 +302,7 @@ def validate_precheck(receipt, purpose="start"):
     if purpose != "resume-local" and after["target_head"] != current["target_head"]:
         raise EvidenceError("Precheck authoritative target has changed")
     if purpose.startswith("resume-"):
-        context = task_context(current)
+        context = task_context(current, require_target=purpose != "resume-local")
         try:
             Path(receipt["cwd"]).resolve().relative_to(context["root"])
         except ValueError:
@@ -311,10 +312,11 @@ def validate_precheck(receipt, purpose="start"):
             raise EvidenceError("Precheck belongs to a different task branch")
         git("merge-base", "--is-ancestor", context["r0"], after["target_head"])
         if purpose == "resume-local":
-            try:
-                git("merge-base", "--is-ancestor", after["target_head"], current["target_head"])
-            except EvidenceError:
-                raise EvidenceError("Precheck target history has rewound or diverged") from None
+            if current["target_head"]:
+                try:
+                    git("merge-base", "--is-ancestor", after["target_head"], current["target_head"])
+                except EvidenceError:
+                    raise EvidenceError("Precheck target history has rewound or diverged") from None
             validate_local_scope(receipt, current, context)