diff --git a/config.json.example b/config.json.example
index 55ef714..0f0f749 100644
--- a/config.json.example
+++ b/config.json.example
@@ -32,7 +32,7 @@
   "ollamaAutoResearch": true,
   "omenTrainingList": "rockyou.txt",
   "omenMaxCandidates": 100000000,
-  "pcfgRuleset": "DEFAULT",
+  "pcfgRuleset": "Default",
   "pcfgMaxCandidates": 50000000,
   "pcfgPrinceLingMaxCandidates": 10000000,
   "check_for_updates": true,
diff --git a/hate_crack/api.py b/hate_crack/api.py
index 080098c..1d54abc 100644
--- a/hate_crack/api.py
+++ b/hate_crack/api.py
@@ -491,79 +491,95 @@ class TransmissionSession:
                     self.remove(entry["id"])
 
 
-def get_hcat_wordlists_dir():
+def _load_config_defaults():
+    """Load config.json.example, searching the same candidate order main.py
+    uses: alongside the resolved config.json (if any), then this package's
+    directory. Returns {} if no readable, well-formed example is found —
+    callers fall back to their own hardcoded defaults in that case.
+    """
+    candidates = []
+    config_path = _resolve_config_path()
+    if config_path:
+        candidates.append(os.path.dirname(config_path))
+    candidates.append(os.path.dirname(os.path.realpath(__file__)))
+    for candidate_dir in candidates:
+        example_path = os.path.join(candidate_dir, "config.json.example")
+        if os.path.isfile(example_path):
+            try:
+                with open(example_path) as f:
+                    return json.load(f)
+            except (OSError, json.JSONDecodeError):
+                continue
+    return {}
+
+
+def _load_merged_config():
+    """config.json.example defaults overlaid with config.json, mirroring
+    the merge main.py performs at import time. Fixes #153: api.py's
+    helpers previously read config.json directly and fell back to their
+    own hardcoded (cwd-relative) defaults when a key was absent, silently
+    diverging from main.py whenever a user's config.json predated a key.
+    """
+    merged = _load_config_defaults()
     config_path = _resolve_config_path()
     if config_path:
         try:
             with open(config_path) as f:
-                config = json.load(f)
-            path = config.get("hcatWordlists")
-            if path:
-                path = os.path.expanduser(path)
-                if not os.path.isabs(path):
-                    path = os.path.normpath(os.path.join(_get_hate_path(), path))
-                os.makedirs(path, exist_ok=True)
-                return path
-        except Exception:
+                merged.update(json.load(f))
+        except (OSError, json.JSONDecodeError):
             pass
+    return merged
+
+
+def get_hcat_wordlists_dir():
+    config = _load_merged_config()
+    path = config.get("hcatWordlists")
+    if path:
+        path = os.path.expanduser(path)
+        if not os.path.isabs(path):
+            path = os.path.normpath(os.path.join(_get_hate_path(), path))
+        os.makedirs(path, exist_ok=True)
+        return path
     default = os.path.join(os.getcwd(), "wordlists")
     os.makedirs(default, exist_ok=True)
     return default
 
 
 def get_rules_dir():
-    config_path = _resolve_config_path()
-    if config_path:
-        try:
-            with open(config_path) as f:
-                config = json.load(f)
-            path = config.get("rules_directory")
-            if path:
-                path = os.path.expanduser(path)
-                if not os.path.isabs(path):
-                    path = os.path.normpath(os.path.join(_get_hate_path(), path))
-                os.makedirs(path, exist_ok=True)
-                return path
-        except Exception:
-            pass
+    config = _load_merged_config()
+    path = config.get("rules_directory")
+    if path:
+        path = os.path.expanduser(path)
+        if not os.path.isabs(path):
+            path = os.path.normpath(os.path.join(_get_hate_path(), path))
+        os.makedirs(path, exist_ok=True)
+        return path
     default = os.path.join(os.getcwd(), "rules")
     os.makedirs(default, exist_ok=True)
     return default
 
 
 def get_hcat_tuning_args():
-    config_path = _resolve_config_path()
-    if config_path:
-        try:
-            with open(config_path) as f:
-                config = json.load(f)
-            tuning = config.get("hcatTuning")
-            if tuning:
-                import shlex
+    config = _load_merged_config()
+    tuning = config.get("hcatTuning")
+    if tuning:
+        import shlex
 
-                return shlex.split(tuning)
-        except Exception:
-            pass
+        return shlex.split(tuning)
     return []
 
 
 def get_hcat_potfile_path():
     """Return the resolved potfile path from config, or the default."""
-    config_path = _resolve_config_path()
-    if config_path:
-        try:
-            with open(config_path) as f:
-                config = json.load(f)
-            if "hcatPotfilePath" in config:
-                raw = (config["hcatPotfilePath"] or "").strip()
-                if raw == "":
-                    return ""
-                expanded = os.path.expanduser(raw)
-                if not os.path.isabs(expanded):
-                    expanded = os.path.join(os.path.dirname(config_path), expanded)
-                return expanded
-        except Exception:
-            pass
+    config = _load_merged_config()
+    if "hcatPotfilePath" in config:
+        raw = (config["hcatPotfilePath"] or "").strip()
+        if raw == "":
+            return ""
+        expanded = os.path.expanduser(raw)
+        if not os.path.isabs(expanded):
+            expanded = os.path.join(_get_hate_path(), expanded)
+        return expanded
     return os.path.expanduser("~/.hashcat/hashcat.potfile")
 
 
diff --git a/hate_crack/main.py b/hate_crack/main.py
index 0006432..2563d57 100755
--- a/hate_crack/main.py
+++ b/hate_crack/main.py
@@ -242,18 +242,36 @@ except json.JSONDecodeError as e:
     print("  2. Delete the file to regenerate from defaults")
     sys.exit(1)
 
+
+def _load_config_defaults(defaults_path):
+    """Load config.json.example, exiting with a clear diagnostic on
+    malformed JSON or an unreadable/missing file (see #155 — a dangling
+    symlink surfaces as FileNotFoundError, which used to escape uncaught).
+    """
+    try:
+        with open(defaults_path) as defaults:
+            return json.load(defaults)
+    except json.JSONDecodeError:
+        print("\nError: config.json.example contains invalid JSON")
+        print(f"  File: {defaults_path}")
+        print("  This is a package installation issue. Try reinstalling hate_crack.")
+        sys.exit(1)
+    except OSError:
+        print("\nError: config.json.example could not be read")
+        print(f"  File: {defaults_path}")
+        if os.path.islink(defaults_path) and not os.path.exists(defaults_path):
+            print(
+                "  This is a dangling symlink: the link exists but its target is missing."
+            )
+        print("  This is a package installation issue. Try reinstalling hate_crack.")
+        sys.exit(1)
+
+
 config_dir = os.path.dirname(_config_path)
 defaults_path = os.path.join(config_dir, "config.json.example")
 if not os.path.isfile(defaults_path):
     defaults_path = os.path.join(_package_path, "config.json.example")
-try:
-    with open(defaults_path) as defaults:
-        default_config = json.load(defaults)
-except json.JSONDecodeError:
-    print("\nError: config.json.example contains invalid JSON")
-    print(f"  File: {defaults_path}")
-    print("  This is a package installation issue. Try reinstalling hate_crack.")
-    sys.exit(1)
+default_config = _load_config_defaults(defaults_path)
 
 for _key, _value in default_config.items():
     if _key not in config_parser:
@@ -463,7 +481,7 @@ ollamaAutoResearch = bool(config_parser.get("ollamaAutoResearch", True))
 
 omenTrainingList = config_parser.get("omenTrainingList", "rockyou.txt")
 omenMaxCandidates = int(config_parser.get("omenMaxCandidates", 100000000))
-pcfgRuleset = config_parser.get("pcfgRuleset", "DEFAULT")
+pcfgRuleset = config_parser.get("pcfgRuleset", "Default")
 pcfgMaxCandidates = int(config_parser.get("pcfgMaxCandidates", 50000000))
 pcfgPrinceLingMaxCandidates = int(
     config_parser.get("pcfgPrinceLingMaxCandidates", 10000000)
@@ -2759,17 +2777,38 @@ def hcatPrince(hcatHashType, hcatHashFile, attack_name="PRINCE"):
             prince_proc.stdout.close()
 
 
+def _resolve_pcfg_ruleset_dir(pcfg_root, ruleset_name):
+    """Resolve ruleset_name against pcfg_root/Rules case-insensitively.
+
+    Older config.json files may have "DEFAULT" backfilled to disk from
+    before the default changed to "Default" (see #148) — match whatever
+    casing exists on disk rather than requiring an exact match.
+    """
+    exact = os.path.join(pcfg_root, "Rules", ruleset_name)
+    if os.path.isdir(exact):
+        return exact
+    rules_root = os.path.join(pcfg_root, "Rules")
+    if os.path.isdir(rules_root):
+        for entry in os.listdir(rules_root):
+            if entry.lower() == ruleset_name.lower():
+                return os.path.join(rules_root, entry)
+    return exact
+
+
 def hcatPCFG(hcatHashType, hcatHashFile):
     """Mode A: pipe pcfg_guesser.py output into hashcat in stdin mode."""
     pcfg_guesser_script = os.path.join(hate_path, "pcfg_cracker", "pcfg_guesser.py")
     if not os.path.isfile(pcfg_guesser_script):
         print(f"pcfg_guesser.py not found at {pcfg_guesser_script}")
         return
+    pcfg_root = os.path.join(hate_path, "pcfg_cracker")
+    resolved_ruleset_dir = _resolve_pcfg_ruleset_dir(pcfg_root, pcfgRuleset)
+    resolved_ruleset_name = os.path.basename(resolved_ruleset_dir)
     pcfg_cmd = [
         sys.executable,
         pcfg_guesser_script,
         "--rule",
-        pcfgRuleset,
+        resolved_ruleset_name,
         "--limit",
         str(pcfgMaxCandidates),
     ]
@@ -2787,7 +2826,9 @@ def hcatPCFG(hcatHashType, hcatHashFile):
         _insert_optimized_flag(hashcat_cmd)
     hashcat_cmd.extend(shlex.split(hcatTuning))
     _append_potfile_arg(hashcat_cmd)
-    pcfg_proc = subprocess.Popen(pcfg_cmd, stdout=subprocess.PIPE)
+    pcfg_proc = subprocess.Popen(
+        pcfg_cmd, stdout=subprocess.PIPE, stdin=subprocess.PIPE
+    )
     _run_hcat_cmd(
         hashcat_cmd,
         attack_name="PCFG",
@@ -2797,6 +2838,8 @@ def hcatPCFG(hcatHashType, hcatHashFile):
     )
     if pcfg_proc.stdout:
         pcfg_proc.stdout.close()
+    if pcfg_proc.stdin:
+        pcfg_proc.stdin.close()
 
 
 def hcatPrinceLing(hcatHashType, hcatHashFile):
@@ -2807,13 +2850,14 @@ def hcatPrinceLing(hcatHashType, hcatHashFile):
     global hcatPrinceBaseList
     pcfg_root = os.path.join(hate_path, "pcfg_cracker")
     prince_ling_script = os.path.join(pcfg_root, "prince_ling.py")
-    ruleset_dir = os.path.join(pcfg_root, "Rules", pcfgRuleset)
+    ruleset_dir = _resolve_pcfg_ruleset_dir(pcfg_root, pcfgRuleset)
     if not os.path.isfile(prince_ling_script):
         print(f"prince_ling.py not found at {prince_ling_script}")
         return
     if not os.path.isdir(ruleset_dir):
         print(f"PCFG ruleset not found: {ruleset_dir}")
         return
+    resolved_ruleset_name = os.path.basename(ruleset_dir)
 
     cache_dir = (
         hcatOptimizedWordlists
@@ -2821,7 +2865,9 @@ def hcatPrinceLing(hcatHashType, hcatHashFile):
         else str(hcatOptimizedWordlists)
     )
     os.makedirs(cache_dir, exist_ok=True)
-    cache_path = os.path.join(cache_dir, f"pcfg_prince_ling_{pcfgRuleset}.txt")
+    cache_path = os.path.join(
+        cache_dir, f"pcfg_prince_ling_{resolved_ruleset_name}.txt"
+    )
     tmp_path = cache_path + ".tmp"
 
     # Staleness check: regenerate iff ruleset dir mtime > cache mtime (strict)
@@ -2838,7 +2884,7 @@ def hcatPrinceLing(hcatHashType, hcatHashFile):
             sys.executable,
             prince_ling_script,
             "--rule",
-            pcfgRuleset,
+            resolved_ruleset_name,
             "--output",
             tmp_path,
             "--size",
diff --git a/tests/test_api_downloads.py b/tests/test_api_downloads.py
index 42d56bc..0afd6ae 100644
--- a/tests/test_api_downloads.py
+++ b/tests/test_api_downloads.py
@@ -397,7 +397,8 @@ class TestGetHcatPotfilePath:
         config_data = {"hcatPotfilePath": "hashcat.potfile"}
         config_file = tmp_path / "config.json"
         config_file.write_text(json.dumps(config_data))
-        with patch("hate_crack.api._resolve_config_path", return_value=str(config_file)):
+        with patch("hate_crack.api._resolve_config_path", return_value=str(config_file)), \
+             patch("hate_crack.api._get_hate_path", return_value=str(tmp_path)):
             result = get_hcat_potfile_path()
         assert result == str(tmp_path / "hashcat.potfile")
 
diff --git a/tests/test_config_defaults_load.py b/tests/test_config_defaults_load.py
new file mode 100644
index 0000000..e5aed53
--- /dev/null
+++ b/tests/test_config_defaults_load.py
@@ -0,0 +1,56 @@
+"""Tests for hate_crack.main's config.json.example defaults loader (#155)."""
+import json
+import os
+
+import pytest
+
+
+@pytest.fixture
+def main_module(hc_module):
+    return hc_module._main
+
+
+def test_missing_defaults_file_exits_with_clear_message(main_module, tmp_path, capsys):
+    missing_path = str(tmp_path / "config.json.example")
+
+    with pytest.raises(SystemExit) as exc_info:
+        main_module._load_config_defaults(missing_path)
+
+    assert exc_info.value.code == 1
+    captured = capsys.readouterr()
+    assert "package installation issue" in captured.out
+    assert missing_path in captured.out
+
+
+def test_dangling_symlink_defaults_file_names_the_cause(main_module, tmp_path, capsys):
+    target = tmp_path / "does-not-exist.json"
+    link_path = tmp_path / "config.json.example"
+    os.symlink(target, link_path)
+
+    with pytest.raises(SystemExit) as exc_info:
+        main_module._load_config_defaults(str(link_path))
+
+    assert exc_info.value.code == 1
+    captured = capsys.readouterr()
+    assert "dangling symlink" in captured.out.lower()
+
+
+def test_malformed_json_defaults_file_exits_with_clear_message(main_module, tmp_path, capsys):
+    bad_path = tmp_path / "config.json.example"
+    bad_path.write_text("{not valid json")
+
+    with pytest.raises(SystemExit) as exc_info:
+        main_module._load_config_defaults(str(bad_path))
+
+    assert exc_info.value.code == 1
+    captured = capsys.readouterr()
+    assert "invalid JSON" in captured.out
+
+
+def test_valid_defaults_file_loads_normally(main_module, tmp_path):
+    good_path = tmp_path / "config.json.example"
+    good_path.write_text(json.dumps({"hcatBin": "hashcat"}))
+
+    result = main_module._load_config_defaults(str(good_path))
+
+    assert result == {"hcatBin": "hashcat"}
diff --git a/tests/test_config_json_example.py b/tests/test_config_json_example.py
index a9bd52e..88d681d 100644
--- a/tests/test_config_json_example.py
+++ b/tests/test_config_json_example.py
@@ -5,18 +5,51 @@ REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 ROOT_EXAMPLE = os.path.join(REPO_ROOT, "config.json.example")
 PACKAGED_EXAMPLE = os.path.join(REPO_ROOT, "hate_crack", "config.json.example")
 
-
-def test_packaged_example_is_symlink_to_root():
-    assert os.path.islink(PACKAGED_EXAMPLE), (
-        "hate_crack/config.json.example must be a symlink to the root "
-        "config.json.example so there is a single source of truth for defaults"
-    )
+# Source of truth for config.json.example's key set. Update this set
+# whenever a config key is added or removed — it's what would have caught
+# the #150 drift (10 missing keys, 4 dead passgpt* keys shipped in a prior
+# release) regardless of whether the packaged copy is a symlink, a
+# dereferenced regular file (wheel/sdist builds), or a flattened copy
+# (git-archive tarball, docker COPY of hate_crack/ alone).
+EXPECTED_KEYS = {
+    "hcatPath", "hcatBin", "hcatTuning", "hcatPotfilePath", "hcatDebugLogPath",
+    "hcatWordlists", "hcatOptimizedWordlists", "rules_directory",
+    "hcatDictionaryWordlist", "hcatCombinationWordlist", "hcatCombinator3Wordlist",
+    "hcatCombinatorXWordlist", "hcatHybridlist", "hcatMiddleCombinatorMasks",
+    "hcatMiddleBaseList", "hcatThoroughCombinatorMasks", "hcatThoroughBaseList",
+    "hcatGoodMeasureBaseList", "hcatPrinceBaseList", "pipalPath", "pipal_count",
+    "bandrelmaxruntime", "bandrel_common_basedwords", "hashview_url",
+    "hashview_api_key", "hashmob_api_key", "ollamaModel", "ollamaNumCtx",
+    "ollamaTimeout", "ollamaMaxSampleLines", "ollamaAutoResearch",
+    "omenTrainingList", "omenMaxCandidates", "pcfgRuleset", "pcfgMaxCandidates",
+    "pcfgPrinceLingMaxCandidates", "check_for_updates", "optimizedKernelAttacks",
+    "notify_enabled", "notify_pushover_token", "notify_pushover_user",
+    "notify_per_crack_enabled", "notify_attack_allowlist",
+    "notify_suppress_in_orchestrators", "notify_max_cracks_per_burst",
+    "notify_poll_interval_seconds",
+}
 
 
-def test_packaged_and_root_examples_have_identical_content():
+def test_root_example_has_expected_keys():
+    with open(ROOT_EXAMPLE) as f:
+        root_config = json.load(f)
+    assert set(root_config.keys()) == EXPECTED_KEYS
+
+
+def test_packaged_example_matches_root_content():
+    """The invariant that matters is content parity, not symlink-ness.
+
+    In the source tree hate_crack/config.json.example is a symlink to the
+    root copy (same inode) — comparing it to itself here is a no-op, and
+    test_root_example_has_expected_keys is the substantive check for that
+    environment. In any tree where the packaged copy is a distinct file
+    (built wheel/sdist, git-archive tarball, docker COPY of hate_crack/
+    alone) this comparison is the one that would actually catch drift.
+    """
+    if os.path.realpath(PACKAGED_EXAMPLE) == os.path.realpath(ROOT_EXAMPLE):
+        return
     with open(ROOT_EXAMPLE) as f:
         root_config = json.load(f)
     with open(PACKAGED_EXAMPLE) as f:
         packaged_config = json.load(f)
-
     assert packaged_config == root_config
diff --git a/tests/test_main_pcfg.py b/tests/test_main_pcfg.py
index a30a92e..3574c33 100644
--- a/tests/test_main_pcfg.py
+++ b/tests/test_main_pcfg.py
@@ -34,6 +34,8 @@ class TestHcatPCFG:
                 captured_calls.append((args, kwargs))
                 self.stdout = MagicMock()
                 self.stdout.close = MagicMock()
+                self.stdin = MagicMock()
+                self.stdin.close = MagicMock()
 
         with patch("hate_crack.main.subprocess.Popen", side_effect=FakeProc), \
              patch("hate_crack.main._run_hcat_cmd") as mock_run, \
@@ -72,12 +74,45 @@ class TestHcatPCFG:
         assert kwargs["companion_procs"] is not None
         assert len(kwargs["companion_procs"]) == 1
 
+    def test_pcfg_child_stdin_stays_open(self, main_module, tmp_path):
+        hash_file = str(tmp_path / "hashes.txt")
+        Path(hash_file).write_text("dummy")
+
+        pcfg_dir = tmp_path / "pcfg_cracker"
+        pcfg_dir.mkdir()
+        (pcfg_dir / "pcfg_guesser.py").write_text("# stub")
+
+        captured_calls = []
+
+        class FakeProc:
+            def __init__(self, *args, **kwargs):
+                captured_calls.append((args, kwargs))
+                self.stdout = MagicMock()
+                self.stdout.close = MagicMock()
+                self.stdin = MagicMock()
+                self.stdin.close = MagicMock()
+
+        with patch("hate_crack.main.subprocess.Popen", side_effect=FakeProc), \
+             patch("hate_crack.main._run_hcat_cmd") as mock_run, \
+             patch.object(main_module, "hate_path", str(tmp_path)), \
+             patch.object(main_module, "hcatBin", "hashcat"), \
+             patch.object(main_module, "hcatTuning", ""), \
+             patch.object(main_module, "hcatPotfilePath", ""), \
+             patch.object(main_module, "generate_session_id", return_value="test_session"):
+            main_module.hcatPCFG("0", hash_file)
+
+        producer_args, producer_kwargs = captured_calls[0]
+        assert producer_kwargs.get("stdin") is not None
+
+        fake_proc = mock_run.call_args.kwargs["companion_procs"][0]
+        assert fake_proc.stdin.close.called
+
 
 class TestHcatPrinceLing:
     def _setup_pcfg_dirs(self, tmp_path, main_module, monkeypatch):
         """Lay out fake pcfg_cracker/Rules/<ruleset>/ and optimized_wordlists/."""
         pcfg_root = tmp_path / "pcfg_cracker"
-        rules_dir = pcfg_root / "Rules" / "DEFAULT"
+        rules_dir = pcfg_root / "Rules" / "Default"
         rules_dir.mkdir(parents=True)
         (rules_dir / "config.txt").write_text("dummy")
         # prince_ling script must "exist" for the function to proceed
@@ -91,7 +126,7 @@ class TestHcatPrinceLing:
 
     def test_regenerates_when_cache_stale(self, main_module, tmp_path, monkeypatch):
         rules_dir, opt_dir = self._setup_pcfg_dirs(tmp_path, main_module, monkeypatch)
-        cache = opt_dir / "pcfg_prince_ling_DEFAULT.txt"
+        cache = opt_dir / "pcfg_prince_ling_Default.txt"
         # Cache exists but is older than ruleset
         cache.write_text("stale")
         old = (rules_dir.stat().st_mtime - 100)
@@ -118,7 +153,7 @@ class TestHcatPrinceLing:
         cmd = run_calls[0]
         assert any("prince_ling.py" in p for p in cmd)
         assert "--rule" in cmd
-        assert cmd[cmd.index("--rule") + 1] == "DEFAULT"
+        assert cmd[cmd.index("--rule") + 1] == "Default"
         # Uses --size, NOT --limit
         assert "--size" in cmd
         assert "--limit" not in cmd
@@ -127,7 +162,7 @@ class TestHcatPrinceLing:
 
     def test_skips_regen_when_cache_fresh(self, main_module, tmp_path, monkeypatch):
         rules_dir, opt_dir = self._setup_pcfg_dirs(tmp_path, main_module, monkeypatch)
-        cache = opt_dir / "pcfg_prince_ling_DEFAULT.txt"
+        cache = opt_dir / "pcfg_prince_ling_Default.txt"
         cache.write_text("fresh")
         # Cache is newer than ruleset
         future = rules_dir.stat().st_mtime + 1000
@@ -156,12 +191,12 @@ class TestHcatPrinceLing:
             main_module.hcatPrinceLing("0", str(tmp_path / "hashes.txt"))
 
         # No real cache file created; tmp file cleaned up
-        assert not (opt_dir / "pcfg_prince_ling_DEFAULT.txt").exists()
-        assert not (opt_dir / "pcfg_prince_ling_DEFAULT.txt.tmp").exists()
+        assert not (opt_dir / "pcfg_prince_ling_Default.txt").exists()
+        assert not (opt_dir / "pcfg_prince_ling_Default.txt.tmp").exists()
 
     def test_restores_hcatPrinceBaseList_on_exception(self, main_module, tmp_path, monkeypatch):
         rules_dir, opt_dir = self._setup_pcfg_dirs(tmp_path, main_module, monkeypatch)
-        cache = opt_dir / "pcfg_prince_ling_DEFAULT.txt"
+        cache = opt_dir / "pcfg_prince_ling_Default.txt"
         cache.write_text("fresh")
         future = rules_dir.stat().st_mtime + 1000
         os.utime(cache, (future, future))
@@ -180,7 +215,7 @@ class TestHcatPrinceLing:
 
     def test_uses_sys_executable(self, main_module, tmp_path, monkeypatch):
         rules_dir, opt_dir = self._setup_pcfg_dirs(tmp_path, main_module, monkeypatch)
-        cache = opt_dir / "pcfg_prince_ling_DEFAULT.txt"
+        cache = opt_dir / "pcfg_prince_ling_Default.txt"
         cache.write_text("stale")
         old = (rules_dir.stat().st_mtime - 100)
         os.utime(cache, (old, old))
@@ -201,3 +236,60 @@ class TestHcatPrinceLing:
             main_module.hcatPrinceLing("0", str(tmp_path / "hashes.txt"))
 
         assert run_calls[0][0] == sys.executable
+
+    def test_resolves_ruleset_case_insensitively(self, main_module, tmp_path, monkeypatch):
+        rules_dir, opt_dir = self._setup_pcfg_dirs(tmp_path, main_module, monkeypatch)
+        # Cache file uses the resolved on-disk basename ("Default"), not the
+        # raw (legacy, all-caps) config value.
+        cache = opt_dir / "pcfg_prince_ling_Default.txt"
+        cache.write_text("stale")
+        old = (rules_dir.stat().st_mtime - 100)
+        os.utime(cache, (old, old))
+
+        # Simulate a config.json predating the default-casing fix, where
+        # "DEFAULT" was backfilled to disk instead of "Default".
+        monkeypatch.setattr(main_module, "pcfgRuleset", "DEFAULT")
+
+        # Force case-sensitive isdir semantics for this test: on
+        # case-insensitive-but-case-preserving filesystems (e.g. macOS
+        # APFS), os.path.isdir(".../DEFAULT") would spuriously match the
+        # real ".../Default" dir, masking the fallback path this test is
+        # meant to exercise (and which is what actually runs on CI's
+        # case-sensitive Linux filesystem).
+        real_isdir = os.path.isdir
+
+        def case_sensitive_isdir(path):
+            parent, name = os.path.split(path)
+            try:
+                return name in os.listdir(parent) and real_isdir(path)
+            except FileNotFoundError:
+                return False
+
+        run_calls = []
+
+        def fake_run(cmd, **kwargs):
+            run_calls.append(cmd)
+            for i, part in enumerate(cmd):
+                if part == "--output":
+                    Path(cmd[i + 1]).write_text("regenerated")
+            class R:
+                returncode = 0
+            return R()
+
+        with patch("hate_crack.main.subprocess.run", side_effect=fake_run), \
+             patch("hate_crack.main.hcatPrince") as mock_prince, \
+             patch("hate_crack.main.os.path.isdir", side_effect=case_sensitive_isdir):
+            main_module.hcatPrinceLing("0", str(tmp_path / "hashes.txt"))
+
+        # Should have found the on-disk "Default" dir and proceeded, not
+        # printed "PCFG ruleset not found" and returned early.
+        assert len(run_calls) == 1
+        cmd = run_calls[0]
+        # The subprocess argv and cache filename must both use the resolved
+        # on-disk basename ("Default"), not the raw monkeypatched "DEFAULT"
+        # value, since prince_ling.py does its own case-sensitive Rules/
+        # lookup internally.
+        assert "--rule" in cmd
+        assert cmd[cmd.index("--rule") + 1] == "Default"
+        assert cache.exists()
+        assert mock_prince.called
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 5d01b81..5e3611e 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -1,3 +1,4 @@
+import json
 import logging
 import os
 import importlib
@@ -98,8 +99,28 @@ def test_get_hcat_wordlists_dir_from_config(tmp_path, monkeypatch):
     assert os.path.isdir(result)
 
 
-def test_get_hcat_wordlists_dir_fallback_cwd(tmp_path, monkeypatch):
+def test_get_hcat_wordlists_dir_no_config_uses_example_default(tmp_path, monkeypatch):
+    """Regression test for #153: with no config.json on disk, api.py must
+    resolve the same default main.py does (config.json.example's
+    hcatWordlists, relative to hate_path) rather than a hardcoded
+    cwd-relative fallback that only main.py knew to avoid.
+    """
     monkeypatch.setattr(api, "_resolve_config_path", lambda: None)
+    monkeypatch.setattr(api, "_get_hate_path", lambda: str(tmp_path))
+
+    result = api.get_hcat_wordlists_dir()
+
+    assert result == str(tmp_path / "wordlists")
+    assert os.path.isdir(result)
+
+
+def test_get_hcat_wordlists_dir_true_fallback_when_no_example(tmp_path, monkeypatch):
+    """Last-resort cwd fallback still applies if config.json.example itself
+    can't be found or read (e.g. hate_crack.main's equivalent loader exits
+    at import time on an unreadable example; api.py's degrades gracefully
+    instead)."""
+    monkeypatch.setattr(api, "_resolve_config_path", lambda: None)
+    monkeypatch.setattr(api, "_load_config_defaults", lambda: {})
     monkeypatch.chdir(tmp_path)
 
     result = api.get_hcat_wordlists_dir()
@@ -120,16 +141,39 @@ def test_get_rules_dir_from_config(tmp_path, monkeypatch):
     assert os.path.isdir(result)
 
 
-def test_get_rules_dir_fallback_cwd(tmp_path, monkeypatch):
+def test_get_rules_dir_no_config_uses_example_default(tmp_path, monkeypatch):
+    """Regression test for #153: api.py's rules_directory default must match
+    main.py's ('./hashcat/rules' from config.json.example), not the
+    hardcoded '<cwd>/rules' this helper used before the fix.
+    """
     monkeypatch.setattr(api, "_resolve_config_path", lambda: None)
-    monkeypatch.chdir(tmp_path)
+    monkeypatch.setattr(api, "_get_hate_path", lambda: str(tmp_path))
 
     result = api.get_rules_dir()
 
-    assert result == str(tmp_path / "rules")
+    assert result == str(tmp_path / "hashcat" / "rules")
     assert os.path.isdir(result)
 
 
+def test_get_hcat_tuning_args_merges_example_default(monkeypatch):
+    monkeypatch.setattr(api, "_resolve_config_path", lambda: None)
+
+    result = api.get_hcat_tuning_args()
+
+    # config.json.example ships hcatTuning: "" — merged default, empty split
+    assert result == []
+
+
+def test_get_hcat_tuning_args_config_overrides_default(tmp_path, monkeypatch):
+    config_file = tmp_path / "config.json"
+    config_file.write_text(json.dumps({"hcatTuning": "-O -w 3"}))
+    monkeypatch.setattr(api, "_resolve_config_path", lambda: str(config_file))
+
+    result = api.get_hcat_tuning_args()
+
+    assert result == ["-O", "-w", "3"]
+
+
 def test_cleanup_torrent_files_removes_only_torrents(tmp_path):
     torrent = tmp_path / "a.torrent"
     keep = tmp_path / "b.txt"