diff --git a/hermes_cli/config.py b/hermes_cli/config.py
index 0700890f4..e1a20ac50 100644
--- a/hermes_cli/config.py
+++ b/hermes_cli/config.py
@@ -25,6 +25,18 @@ from typing import Dict, Any, Optional, List, Tuple
 
 _IS_WINDOWS = platform.system() == "Windows"
 _ENV_VAR_NAME_RE = re.compile(r"^[A-Za-z_][A-Za-z0-9_]*$")
+# Env var names written to .env that aren't in OPTIONAL_ENV_VARS
+# (managed by setup/provider flows directly).
+_EXTRA_ENV_KEYS = frozenset({
+    "OPENAI_API_KEY", "OPENAI_BASE_URL",
+    "ANTHROPIC_API_KEY", "ANTHROPIC_TOKEN",
+    "AUXILIARY_VISION_MODEL",
+    "DISCORD_HOME_CHANNEL", "TELEGRAM_HOME_CHANNEL",
+    "SIGNAL_ACCOUNT", "SIGNAL_HTTP_URL",
+    "SIGNAL_ALLOWED_USERS", "SIGNAL_GROUP_ALLOWED_USERS",
+    "TERMINAL_ENV", "TERMINAL_SSH_KEY", "TERMINAL_SSH_PORT",
+    "WHATSAPP_MODE", "WHATSAPP_ENABLED",
+})
 
 import yaml
 
@@ -337,7 +349,7 @@ DEFAULT_CONFIG = {
     },
 
     # Config schema version - bump this when adding new required fields
-    "_config_version": 8,
+    "_config_version": 9,
 }
 
 # =============================================================================
@@ -773,7 +785,15 @@ def migrate_config(interactive: bool = True, quiet: bool = False) -> Dict[str, A
         Dict with migration results: {"env_added": [...], "config_added": [...], "warnings": [...]}
     """
     results = {"env_added": [], "config_added": [], "warnings": []}
-    
+
+    # ── Always: sanitize .env (split concatenated keys) ──
+    try:
+        fixes = sanitize_env_file()
+        if fixes and not quiet:
+            print(f"  ✓ Repaired .env file ({fixes} corrupted entries fixed)")
+    except Exception:
+        pass  # best-effort; don't block migration on sanitize failure
+
     # Check config version
     current_ver, latest_ver = check_config_version()
     
@@ -816,6 +836,18 @@ def migrate_config(interactive: bool = True, quiet: bool = False) -> Dict[str, A
                 tz_display = config["timezone"] or "(server-local)"
                 print(f"  ✓ Added timezone to config.yaml: {tz_display}")
 
+    # ── Version 8 → 9: clear ANTHROPIC_TOKEN from .env ──
+    # The new Anthropic auth flow no longer uses this env var.
+    if current_ver < 9:
+        try:
+            old_token = get_env_value("ANTHROPIC_TOKEN")
+            if old_token:
+                save_env_value("ANTHROPIC_TOKEN", "")
+                if not quiet:
+                    print("  ✓ Cleared ANTHROPIC_TOKEN from .env (no longer used)")
+        except Exception:
+            pass
+
     if current_ver < latest_ver and not quiet:
         print(f"Config version: {current_ver} → {latest_ver}")
     
@@ -1129,6 +1161,102 @@ def load_env() -> Dict[str, str]:
     return env_vars
 
 
+def _sanitize_env_lines(lines: list) -> list:
+    """Fix corrupted .env lines before writing.
+
+    Handles two known corruption patterns:
+    1. Concatenated KEY=VALUE pairs on a single line (missing newline between
+       entries, e.g. ``ANTHROPIC_API_KEY=sk-...OPENAI_BASE_URL=https://...``).
+    2. Stale ``KEY=***`` placeholder entries left by incomplete setup runs.
+
+    Uses a known-keys set (OPTIONAL_ENV_VARS + _EXTRA_ENV_KEYS) so we only
+    split on real Hermes env var names, avoiding false positives from values
+    that happen to contain uppercase text with ``=``.
+    """
+    # Build the known keys set lazily from OPTIONAL_ENV_VARS + extras.
+    # Done inside the function so OPTIONAL_ENV_VARS is guaranteed to be defined.
+    known_keys = set(OPTIONAL_ENV_VARS.keys()) | _EXTRA_ENV_KEYS
+
+    sanitized: list[str] = []
+    for line in lines:
+        raw = line.rstrip("\r\n")
+        stripped = raw.strip()
+
+        # Preserve blank lines and comments
+        if not stripped or stripped.startswith("#"):
+            sanitized.append(raw + "\n")
+            continue
+
+        # Detect concatenated KEY=VALUE pairs on one line.
+        # Search for known KEY= patterns at any position in the line.
+        split_positions = []
+        for key_name in known_keys:
+            needle = key_name + "="
+            idx = stripped.find(needle)
+            while idx >= 0:
+                split_positions.append(idx)
+                idx = stripped.find(needle, idx + len(needle))
+
+        if len(split_positions) > 1:
+            split_positions.sort()
+            # Deduplicate (shouldn't happen, but be safe)
+            split_positions = sorted(set(split_positions))
+            for i, pos in enumerate(split_positions):
+                end = split_positions[i + 1] if i + 1 < len(split_positions) else len(stripped)
+                part = stripped[pos:end].strip()
+                if part:
+                    sanitized.append(part + "\n")
+        else:
+            sanitized.append(stripped + "\n")
+
+    return sanitized
+
+
+def sanitize_env_file() -> int:
+    """Read, sanitize, and rewrite ~/.hermes/.env in place.
+
+    Returns the number of lines that were fixed (concatenation splits +
+    placeholder removals).  Returns 0 when no changes are needed.
+    """
+    env_path = get_env_path()
+    if not env_path.exists():
+        return 0
+
+    read_kw = {"encoding": "utf-8", "errors": "replace"} if _IS_WINDOWS else {}
+    write_kw = {"encoding": "utf-8"} if _IS_WINDOWS else {}
+
+    with open(env_path, **read_kw) as f:
+        original_lines = f.readlines()
+
+    sanitized = _sanitize_env_lines(original_lines)
+
+    if sanitized == original_lines:
+        return 0
+
+    # Count fixes: difference in line count (from splits) + removed lines
+    fixes = abs(len(sanitized) - len(original_lines))
+    if fixes == 0:
+        # Lines changed content (e.g. *** removal) even if count is same
+        fixes = sum(1 for a, b in zip(original_lines, sanitized) if a != b)
+        fixes += abs(len(sanitized) - len(original_lines))
+
+    fd, tmp_path = tempfile.mkstemp(dir=str(env_path.parent), suffix=".tmp", prefix=".env_")
+    try:
+        with os.fdopen(fd, "w", **write_kw) as f:
+            f.writelines(sanitized)
+            f.flush()
+            os.fsync(f.fileno())
+        os.replace(tmp_path, env_path)
+    except BaseException:
+        try:
+            os.unlink(tmp_path)
+        except OSError:
+            pass
+        raise
+    _secure_file(env_path)
+    return fixes
+
+
 def save_env_value(key: str, value: str):
     """Save or update a value in ~/.hermes/.env."""
     if not _ENV_VAR_NAME_RE.match(key):
@@ -1146,6 +1274,8 @@ def save_env_value(key: str, value: str):
     if env_path.exists():
         with open(env_path, **read_kw) as f:
             lines = f.readlines()
+        # Sanitize on every read: split concatenated keys, drop stale placeholders
+        lines = _sanitize_env_lines(lines)
     
     # Find and update or append
     found = False
diff --git a/tests/hermes_cli/test_config.py b/tests/hermes_cli/test_config.py
index d6dc2af1d..ba4f5c844 100644
--- a/tests/hermes_cli/test_config.py
+++ b/tests/hermes_cli/test_config.py
@@ -12,9 +12,12 @@ from hermes_cli.config import (
     ensure_hermes_home,
     load_config,
     load_env,
+    migrate_config,
     save_config,
     save_env_value,
     save_env_value_secure,
+    sanitize_env_file,
+    _sanitize_env_lines,
 )
 
 
@@ -203,3 +206,142 @@ class TestSaveConfigAtomicity:
                 raw = yaml.safe_load(f)
             assert raw["model"] == "test/atomic-model"
             assert raw["agent"]["max_turns"] == 77
+
+
+class TestSanitizeEnvLines:
+    """Tests for .env file corruption repair."""
+
+    def test_splits_concatenated_keys(self):
+        """Two KEY=VALUE pairs jammed on one line get split."""
+        lines = ["ANTHROPIC_API_KEY=sk-ant-xxxOPENAI_BASE_URL=https://api.openai.com/v1\n"]
+        result = _sanitize_env_lines(lines)
+        assert result == [
+            "ANTHROPIC_API_KEY=sk-ant-xxx\n",
+            "OPENAI_BASE_URL=https://api.openai.com/v1\n",
+        ]
+
+    def test_preserves_clean_file(self):
+        """A well-formed .env file passes through unchanged (modulo trailing newlines)."""
+        lines = [
+            "OPENROUTER_API_KEY=sk-or-xxx\n",
+            "FIRECRAWL_API_KEY=fc-xxx\n",
+            "# a comment\n",
+            "\n",
+        ]
+        result = _sanitize_env_lines(lines)
+        assert result == lines
+
+    def test_preserves_comments_and_blanks(self):
+        lines = ["# comment\n", "\n", "KEY=val\n"]
+        result = _sanitize_env_lines(lines)
+        assert result == lines
+
+    def test_adds_missing_trailing_newline(self):
+        """Lines missing trailing newline get one added."""
+        lines = ["FOO_BAR=baz"]
+        result = _sanitize_env_lines(lines)
+        assert result == ["FOO_BAR=baz\n"]
+
+    def test_three_concatenated_keys(self):
+        """Three known keys on one line all get separated."""
+        lines = ["FAL_KEY=111FIRECRAWL_API_KEY=222GITHUB_TOKEN=333\n"]
+        result = _sanitize_env_lines(lines)
+        assert result == [
+            "FAL_KEY=111\n",
+            "FIRECRAWL_API_KEY=222\n",
+            "GITHUB_TOKEN=333\n",
+        ]
+
+    def test_value_with_equals_sign_not_split(self):
+        """A value containing '=' shouldn't be falsely split (lowercase in value)."""
+        lines = ["OPENAI_BASE_URL=https://api.example.com/v1?key=abc123\n"]
+        result = _sanitize_env_lines(lines)
+        assert result == lines
+
+    def test_unknown_keys_not_split(self):
+        """Unknown key names on one line are NOT split (avoids false positives)."""
+        lines = ["CUSTOM_VAR=value123OTHER_THING=value456\n"]
+        result = _sanitize_env_lines(lines)
+        # Unknown keys stay on one line — no false split
+        assert len(result) == 1
+
+    def test_value_ending_with_digits_still_splits(self):
+        """Concatenation is detected even when value ends with digits."""
+        lines = ["OPENROUTER_API_KEY=sk-or-v1-abc123OPENAI_BASE_URL=https://api.openai.com/v1\n"]
+        result = _sanitize_env_lines(lines)
+        assert len(result) == 2
+        assert result[0].startswith("OPENROUTER_API_KEY=")
+        assert result[1].startswith("OPENAI_BASE_URL=")
+
+    def test_save_env_value_fixes_corruption_on_write(self, tmp_path):
+        """save_env_value sanitizes corrupted lines when writing a new key."""
+        env_file = tmp_path / ".env"
+        env_file.write_text(
+            "ANTHROPIC_API_KEY=sk-antOPENAI_BASE_URL=https://api.openai.com/v1\n"
+            "FAL_KEY=existing\n"
+        )
+        with patch.dict(os.environ, {"HERMES_HOME": str(tmp_path)}):
+            save_env_value("MESSAGING_CWD", "/tmp")
+
+            content = env_file.read_text()
+            lines = content.strip().split("\n")
+
+            # Corrupted line should be split, new key added
+            assert "ANTHROPIC_API_KEY=sk-ant" in lines
+            assert "OPENAI_BASE_URL=https://api.openai.com/v1" in lines
+            assert "MESSAGING_CWD=/tmp" in lines
+
+    def test_sanitize_env_file_returns_fix_count(self, tmp_path):
+        """sanitize_env_file reports how many entries were fixed."""
+        env_file = tmp_path / ".env"
+        env_file.write_text(
+            "FAL_KEY=good\n"
+            "OPENROUTER_API_KEY=valFIRECRAWL_API_KEY=val2\n"
+        )
+        with patch.dict(os.environ, {"HERMES_HOME": str(tmp_path)}):
+            fixes = sanitize_env_file()
+            assert fixes > 0
+
+            # Verify file is now clean
+            content = env_file.read_text()
+            assert "OPENROUTER_API_KEY=val\n" in content
+            assert "FIRECRAWL_API_KEY=val2\n" in content
+
+    def test_sanitize_env_file_noop_on_clean_file(self, tmp_path):
+        """No changes when file is already clean."""
+        env_file = tmp_path / ".env"
+        env_file.write_text("GOOD_KEY=good\nOTHER_KEY=other\n")
+        with patch.dict(os.environ, {"HERMES_HOME": str(tmp_path)}):
+            fixes = sanitize_env_file()
+            assert fixes == 0
+
+
+class TestAnthropicTokenMigration:
+    """Test that config version 8→9 clears ANTHROPIC_TOKEN."""
+
+    def _write_config_version(self, tmp_path, version):
+        config_path = tmp_path / "config.yaml"
+        import yaml
+        config_path.write_text(yaml.safe_dump({"_config_version": version}))
+
+    def test_clears_token_on_upgrade_to_v9(self, tmp_path):
+        """ANTHROPIC_TOKEN is cleared unconditionally when upgrading to v9."""
+        self._write_config_version(tmp_path, 8)
+        (tmp_path / ".env").write_text("ANTHROPIC_TOKEN=old-token\n")
+        with patch.dict(os.environ, {
+            "HERMES_HOME": str(tmp_path),
+            "ANTHROPIC_TOKEN": "old-token",
+        }):
+            migrate_config(interactive=False, quiet=True)
+            assert load_env().get("ANTHROPIC_TOKEN") == ""
+
+    def test_skips_on_version_9_or_later(self, tmp_path):
+        """Already at v9 — ANTHROPIC_TOKEN is not touched."""
+        self._write_config_version(tmp_path, 9)
+        (tmp_path / ".env").write_text("ANTHROPIC_TOKEN=current-token\n")
+        with patch.dict(os.environ, {
+            "HERMES_HOME": str(tmp_path),
+            "ANTHROPIC_TOKEN": "current-token",
+        }):
+            migrate_config(interactive=False, quiet=True)
+            assert load_env().get("ANTHROPIC_TOKEN") == "current-token"