diff --git a/raven/config/update.py b/raven/config/update.py
index 8ee882ec5..1a7917dd2 100644
--- a/raven/config/update.py
+++ b/raven/config/update.py
@@ -248,9 +248,15 @@ def _apply(_text: str | None) -> tuple[str | None, tuple[list[str], bool]]:
             sf_key = "skillForge"
         elif isinstance(data.get("skill_forge"), dict):
             sf_key = "skill_forge"
+        elif "skill_forge" in data and "skillForge" not in data:
+            sf_key = "skill_forge"
         else:
             sf_key = "skillForge"
-        section = data.setdefault(sf_key, {})
+        section = data.get(sf_key)
+        if section is None:
+            section = data[sf_key] = {}
+        elif not isinstance(section, dict):
+            raise ValueError(f"{sf_key} must be an object or null")
         current = [str(x) for x in (section.get("blocklist") or [])]
         lowered = {x.casefold() for x in current}
         if blocked:
diff --git a/tests/test_cli_skill_commands.py b/tests/test_cli_skill_commands.py
index 616eb5452..1614cb606 100644
--- a/tests/test_cli_skill_commands.py
+++ b/tests/test_cli_skill_commands.py
@@ -207,9 +207,35 @@ def test_skill_unblock_removes_from_config(tmp_config: Path) -> None:
     runner.invoke(app, ["skill", "block", "other"])
     r = runner.invoke(app, ["skill", "unblock", "Tag-Memory"])
     assert r.exit_code == 0
+    assert "skillForge" not in r.stdout
     assert _read_blocklist(tmp_config) == ["other"]
 
 
+@pytest.mark.parametrize("spelling", ["skillForge", "skill_forge"])
+def test_skill_block_and_unblock_accept_a_null_section(tmp_config: Path, spelling: str) -> None:
+    import json
+
+    from raven.config.loader import load_config
+    from raven.config.raven import load_raven_config
+
+    tmp_config.write_text(json.dumps({spelling: None}), encoding="utf-8")
+    load_config(tmp_config)
+    empty = tmp_config.read_bytes()
+    assert runner.invoke(app, ["skill", "unblock", "absent"]).exit_code == 0
+    assert tmp_config.read_bytes() == empty
+    result = runner.invoke(app, ["skill", "block", "tag-memory"])
+    assert result.exit_code == 0, result.output
+    assert json.loads(tmp_config.read_text(encoding="utf-8")) == {spelling: {"blocklist": ["tag-memory"]}}
+    assert load_raven_config(config_path=tmp_config).skill_forge.blocklist == ["tag-memory"]
+    before = tmp_config.read_bytes()
+    assert runner.invoke(app, ["skill", "block", "TAG-MEMORY"]).exit_code == 0
+    assert tmp_config.read_bytes() == before
+    result = runner.invoke(app, ["skill", "unblock", "TAG-MEMORY"])
+    assert result.exit_code == 0
+    assert "Unblocked" in result.stdout and "skillForge" not in result.stdout
+    assert json.loads(tmp_config.read_text(encoding="utf-8")) == {spelling: {"blocklist": []}}
+
+
 def test_skill_block_reports_the_block_it_wrote_on_a_snake_config(tmp_config: Path) -> None:
     """The result line must not name a key this write did not use.
 
diff --git a/tests/test_config_update.py b/tests/test_config_update.py
index ddfbd1260..aab8958f2 100644
--- a/tests/test_config_update.py
+++ b/tests/test_config_update.py
@@ -548,6 +548,16 @@ def test_skill_block_writes_camel_into_empty_config(cfg_path: Path) -> None:
     assert _read(cfg_path)["skillForge"] == {"blocklist": ["alpha"]}
 
 
+@pytest.mark.parametrize("spelling", ["skillForge", "skill_forge"])
+@pytest.mark.parametrize("invalid", [[], 1, "invalid"])
+def test_skill_block_preserves_an_invalid_section(cfg_path, spelling, invalid):
+    cfg_path.write_text(json.dumps({spelling: invalid}), encoding="utf-8")
+    before = cfg_path.read_bytes()
+    with pytest.raises(ValueError, match="object or null"):
+        set_skill_blocked("alpha", True, config_path=cfg_path)
+    assert cfg_path.read_bytes() == before
+
+
 def test_skill_block_respects_existing_snake_casing(cfg_path: Path) -> None:
     cfg_path.write_text(
         json.dumps({"skill_forge": {"auto_install": "off"}}),