diff --git a/MIGRATION_v3_to_v4.md b/MIGRATION_v3_to_v4.md
index 7b406e56c..42b5c9cc7 100644
--- a/MIGRATION_v3_to_v4.md
+++ b/MIGRATION_v3_to_v4.md
@@ -211,6 +211,40 @@ if package.status == PackageStatus.active: ...
 if media_buy.status == MediaBuyStatus.active: ...
 ```
 
+### `MediaBuyStatus.pending_activation` → split
+
+The single `pending_activation` enum value was split into two
+distinct states based on cause. The codemod flags every reference; the
+correct replacement is per-call-site.
+
+| Cause                              | Replacement |
+| ---                                | ---         |
+| Buy is scheduled and waiting for its start time | `MediaBuyStatus.pending_start` |
+| Buy is waiting on creative approval / asset processing | `MediaBuyStatus.pending_creatives` |
+
+**Before (v3.x):**
+```python
+if media_buy.status == MediaBuyStatus.pending_activation:
+    notify_trafficker(media_buy)
+```
+
+**After (v4.0):**
+```python
+if media_buy.status in (
+    MediaBuyStatus.pending_start,
+    MediaBuyStatus.pending_creatives,
+):
+    notify_trafficker(media_buy)
+```
+
+When the original branch only fired for one cause, narrow to the right
+state (e.g. only `pending_creatives` for creative-review notifications).
+A blanket replacement to either single value is almost always wrong —
+the spec split was driven by adopters needing distinct behaviour for
+the two cases. The wire enum still accepts `pending` as a legacy alias
+for `pending_start` (per the schema description), so existing buyer
+clients reading older payloads keep working without code changes.
+
 ### `ResolvedBrand.brand_manifest` field removed
 
 `RegistryClient.lookup_brand()` returns a `ResolvedBrand` whose
diff --git a/src/adcp/migrate/v3_to_v4.py b/src/adcp/migrate/v3_to_v4.py
index 0607f141c..c0eeb70c6 100644
--- a/src/adcp/migrate/v3_to_v4.py
+++ b/src/adcp/migrate/v3_to_v4.py
@@ -101,8 +101,23 @@
 
 # Attribute accesses that moved / were removed. Flagged not rewritten
 # because context determines the right replacement.
-REMOVED_ATTRIBUTE_ACCESSES: dict[str, str] = {
-    ".brand_manifest": ("ResolvedBrand.brand_manifest removed — use .brand instead"),
+#
+# Each entry is keyed on the dotted attribute including the leading dot
+# (the regex below requires it for word-boundary safety) and maps to a
+# ``(hint, migration_anchor)`` tuple. ``migration_anchor`` may be
+# ``None`` for entries without a dedicated migration-guide section.
+REMOVED_ATTRIBUTE_ACCESSES: dict[str, tuple[str, str | None]] = {
+    ".brand_manifest": (
+        "ResolvedBrand.brand_manifest removed — use .brand instead",
+        None,
+    ),
+    ".pending_activation": (
+        "MediaBuyStatus.pending_activation was split into "
+        "`pending_start` (schedule-future buys) and `pending_creatives` "
+        "(buys waiting on creative approval). The correct replacement "
+        "is per-call-site — review each usage manually.",
+        "mediabuystatuspending_activation--split",
+    ),
 }
 
 
@@ -386,7 +401,7 @@ def scan_file(path: Path, *, apply_changes: bool) -> tuple[list[Finding], str |
         # Removed attribute accesses (.brand_manifest etc.). Regex with
         # trailing word boundary prevents false-positives on
         # ``.brand_manifest_v2``, ``.brand_manifest_override``, etc.
-        for attr, hint in REMOVED_ATTRIBUTE_ACCESSES.items():
+        for attr, (attr_hint, attr_anchor) in REMOVED_ATTRIBUTE_ACCESSES.items():
             for match in _REMOVED_ATTRIBUTE_PATTERNS[attr].finditer(line):
                 findings.append(
                     Finding(
@@ -395,7 +410,8 @@ def scan_file(path: Path, *, apply_changes: bool) -> tuple[list[Finding], str |
                         line=lineno,
                         column=match.start() + 1,
                         before=attr,
-                        hint=hint,
+                        hint=attr_hint,
+                        migration_anchor=attr_anchor,
                     )
                 )
 
diff --git a/tests/test_migrate_v3_to_v4.py b/tests/test_migrate_v3_to_v4.py
index 941973ef8..1d90863af 100644
--- a/tests/test_migrate_v3_to_v4.py
+++ b/tests/test_migrate_v3_to_v4.py
@@ -271,6 +271,49 @@ def test_flags_removed_attribute_accesses(tmp_path: Path) -> None:
     assert attr[0].before == ".brand_manifest"
 
 
+def test_flags_pending_activation_split(tmp_path: Path) -> None:
+    """``MediaBuyStatus.pending_activation`` was split into
+    ``pending_start`` and ``pending_creatives``. Flag every reference
+    with the per-call-site decision hint and the migration anchor."""
+    _write(
+        tmp_path,
+        "code.py",
+        "if media_buy.status == MediaBuyStatus.pending_activation:\n" "    notify(media_buy)\n",
+    )
+
+    report = v3_to_v4.run(tmp_path, apply_changes=False)
+
+    attr = [
+        f
+        for f in report.flagged
+        if f.kind == "flag_attribute" and f.before == ".pending_activation"
+    ]
+    assert len(attr) == 1
+    assert "pending_start" in (attr[0].hint or "")
+    assert "pending_creatives" in (attr[0].hint or "")
+    assert attr[0].migration_anchor == "mediabuystatuspending_activation--split"
+
+
+def test_pending_activation_word_boundary_no_false_positive(tmp_path: Path) -> None:
+    """``.pending_activation_v2`` / ``.pending_activation_count`` are
+    adopter extensions that share the prefix; the trailing word
+    boundary keeps them out of the flagged set."""
+    _write(
+        tmp_path,
+        "code.py",
+        "x = stats.pending_activation_count\n" "y = obj.pending_activation_v2 = True\n",
+    )
+
+    report = v3_to_v4.run(tmp_path, apply_changes=False)
+
+    flagged = [
+        f
+        for f in report.flagged
+        if f.kind == "flag_attribute" and f.before == ".pending_activation"
+    ]
+    assert flagged == [], f"false-positive on pending_activation_* suffixes: {flagged}"
+
+
 def test_brand_manifest_word_boundary_no_false_positive(tmp_path: Path) -> None:
     """``.brand_manifest_v2`` / ``.brand_manifest_override`` are
     seller-specific extensions that happen to share a prefix. They