diff --git a/Sensor/README.md b/Sensor/README.md
index 89cbbd2..1b47d69 100644
--- a/Sensor/README.md
+++ b/Sensor/README.md
@@ -112,6 +112,9 @@ are read:
 
 - **SQLite** (current releases) — `opencode.db`, or `opencode-<channel>.db` on
   non-stable channels. Opened read-only so a running opencode process is never disturbed.
+  A database is used only if it contains the `session`, `message` and `part` tables;
+  otherwise the other candidate databases and then the JSON tree are tried, and a
+  database without those tables is reported as `unsupported_schema`.
 - **JSON file tree** (older releases) — a `storage/` directory of per-session,
   per-message and per-part JSON files, in both the project-scoped and legacy layouts.
 
diff --git a/Sensor/adr_sensor/parsers/opencode_parser.py b/Sensor/adr_sensor/parsers/opencode_parser.py
index 8223c67..c20b59f 100644
--- a/Sensor/adr_sensor/parsers/opencode_parser.py
+++ b/Sensor/adr_sensor/parsers/opencode_parser.py
@@ -17,7 +17,9 @@
    conversation record for local CLI usage; the newer ``session_message`` /
    ``event`` tables are an additional event-sourced projection used for other
    purposes and were empty in every real session captured while building this
-   parser, so they are not read here.
+   parser, so they are not read here. A database is only used if it has the
+   ``session`` / ``message`` / ``part`` tables; otherwise the remaining
+   candidate databases and then the JSON tree below are tried.
 
 2. JSON file tree (older, pre-SQLite versions): a ``storage/`` directory holding
    one JSON file per session / message / part. Both the newer project-scoped
@@ -79,10 +81,16 @@
     }
 )
 
+# Tables a SQLite database must contain to be read as opencode session history.
+REQUIRED_SQLITE_TABLES = frozenset({"session", "message", "part"})
+
 
 class OpencodeParser(BaseParser):
     """Parser for opencode session logs (SQLite and legacy JSON backends)."""
 
+    # Set by _detect_backend when databases exist but none has the session tables.
+    _schema_mismatch = False
+
     def __init__(self, max_age_days: int = MAX_LOG_AGE_DAYS):
         self.max_age_days = max_age_days
         self.base_dir, self.backend, self.db_path = self._detect_backend()
@@ -112,38 +120,71 @@ def _candidate_base_dirs() -> List[Path]:
         return unique
 
     @staticmethod
-    def _find_db_file(base: Path) -> Optional[Path]:
-        """Locate the opencode SQLite database under a candidate data directory.
+    def _find_db_files(base: Path) -> List[Path]:
+        """List candidate opencode SQLite databases under a data directory.
 
         The ``OPENCODE_DB`` environment variable can override the filename (or be
         an absolute path / ``:memory:``); otherwise the file is ``opencode.db``
         for stable channels or ``opencode-<channel>.db`` for anything else (e.g.
         a nightly build), so we fall back to globbing for that pattern too.
+        Candidates are returned in that priority order, without duplicates.
         """
+        candidates: List[Path] = []
+
         env_db = os.environ.get("OPENCODE_DB")
         if env_db and env_db != ":memory:":
             candidate = Path(env_db)
             if not candidate.is_absolute():
                 candidate = base / env_db
             if candidate.exists():
-                return candidate
+                candidates.append(candidate)
 
         default = base / "opencode.db"
-        if default.exists():
-            return default
+        if default.exists() and default not in candidates:
+            candidates.append(default)
 
         if base.exists():
             for candidate in sorted(base.glob("opencode-*.db")):
-                if candidate.exists():
-                    return candidate
-        return None
+                if candidate.exists() and candidate not in candidates:
+                    candidates.append(candidate)
+        return candidates
+
+    @staticmethod
+    def _find_db_file(base: Path) -> Optional[Path]:
+        """Return the highest-priority candidate database, if any."""
+        candidates = OpencodeParser._find_db_files(base)
+        return candidates[0] if candidates else None
+
+    @staticmethod
+    def _has_session_schema(db_path: Path) -> bool:
+        """Return True if the database has opencode's session tables."""
+        conn = None
+        try:
+            conn = sqlite3.connect(f"file:{db_path}?mode=ro", uri=True)
+            rows = conn.execute("SELECT name FROM sqlite_master WHERE type = 'table'").fetchall()
+        except (sqlite3.Error, OSError):
+            return False
+        finally:
+            if conn is not None:
+                conn.close()
+        return REQUIRED_SQLITE_TABLES <= {row[0] for row in rows}
 
     def _detect_backend(self) -> Tuple[Path, Optional[str], Optional[Path]]:
-        """Return (base_dir, backend, db_path) where backend is 'sqlite', 'json' or None."""
+        """Return (base_dir, backend, db_path) where backend is 'sqlite', 'json' or None.
+
+        A database is selected only if it contains the session tables; otherwise
+        the remaining candidates and then the JSON ``storage/`` tree are tried.
+        This runs before per-run diagnostics are reset, so a database without
+        the expected tables is only remembered here and reported by parse_all.
+        """
+        self._schema_mismatch = False
         for base in self._candidate_base_dirs():
-            db_path = self._find_db_file(base)
-            if db_path is not None:
-                return base, "sqlite", db_path
+            db_files = self._find_db_files(base)
+            for db_path in db_files:
+                if self._has_session_schema(db_path):
+                    return base, "sqlite", db_path
+            if db_files:
+                self._schema_mismatch = True
             storage_dir = base / "storage"
             if storage_dir.exists():
                 return base, "json", None
@@ -160,9 +201,16 @@ def parse_all(self) -> List[AgentEvent]:
 
         if self.backend == "json":
             storage_dir = self.base_dir / "storage"
+            if self._schema_mismatch:
+                logger.info("[OPENCODE] SQLite database lacks the session tables; reading JSON storage")
             logger.info("[OPENCODE] Reading JSON logs from %s", storage_dir)
             return self._parse_json_storage(storage_dir)
 
+        if self._schema_mismatch:
+            logger.info("[OPENCODE] Database found but it does not contain the expected session tables")
+            self.record_diagnostic("unsupported_schema")
+            return []
+
         logger.info("[OPENCODE] No logs found at %s", self.base_dir)
         self.record_diagnostic("input_missing")
         return []
@@ -193,9 +241,23 @@ def _parse_sqlite(self, db_path: Path) -> List[AgentEvent]:
                     )
                     if entry and entry.has_meaningful_content():
                         entries.append(entry)
+                except sqlite3.OperationalError as e:
+                    # A missing table affects every session: stop and report it once.
+                    if "no such table" in str(e):
+                        raise
+                    self.record_diagnostic("session_build_error")
+                    print(f"[OPENCODE] Error processing session {session_id}: {e}")
                 except Exception as e:
                     self.record_diagnostic("session_build_error")
                     logger.warning("[OPENCODE] Error processing session %s: %s", session_id, e)
+        except sqlite3.OperationalError as e:
+            # The schema can change between backend detection and parsing.
+            if "no such table" in str(e):
+                self.record_diagnostic("unsupported_schema")
+                logger.warning("[OPENCODE] Expected session tables not found in database")
+            else:
+                self.record_diagnostic("database_error")
+                logger.warning("[OPENCODE] Error reading database: %s", e)
         except Exception as e:
             self.record_diagnostic("database_error")
             logger.error("[OPENCODE] Error reading database: %s", e)
diff --git a/Sensor/tests/test_parser_diagnostics.py b/Sensor/tests/test_parser_diagnostics.py
index 7c79a0e..6500549 100644
--- a/Sensor/tests/test_parser_diagnostics.py
+++ b/Sensor/tests/test_parser_diagnostics.py
@@ -151,7 +151,7 @@ def test_diagnostics_survive_when_every_record_is_rejected(tmp_path, parser_clas
     assert parser.get_diagnostics()["record_shape_error"] >= 1
 
 
-@pytest.mark.parametrize("parser_class", [CursorParser, OpencodeParser, WarpParser])
+@pytest.mark.parametrize("parser_class", [CursorParser, WarpParser])
 def test_incompatible_database_reports_failure(tmp_path, parser_class):
     parser = isolated_parser(parser_class, tmp_path)
     parser.db_path = tmp_path / "synthetic.db"
@@ -162,6 +162,16 @@ def test_incompatible_database_reports_failure(tmp_path, parser_class):
     assert parser.get_diagnostics()["database_error"] >= 1
 
 
+def test_opencode_database_without_tables_reports_schema_drift(tmp_path):
+    parser = isolated_parser(OpencodeParser, tmp_path)
+    parser.db_path = tmp_path / "synthetic.db"
+    parser.backend = "sqlite"
+    with sqlite3.connect(parser.db_path):
+        pass
+    assert parser.parse_all() == []
+    assert parser.get_diagnostics() == {"unsupported_schema": 1}
+
+
 def test_dsh_new_generation_reports_schema_drift_without_reading_payload(tmp_path):
     parser = isolated_parser(DshParser, tmp_path)
     parser.base_path = tmp_path
diff --git a/Sensor/tests/test_parsers.py b/Sensor/tests/test_parsers.py
index 2db5dbc..244d764 100644
--- a/Sensor/tests/test_parsers.py
+++ b/Sensor/tests/test_parsers.py
@@ -2119,6 +2119,14 @@ def _build_opencode_db(db_path, sessions, messages, parts):
     conn.close()
 
 
+def _build_non_opencode_db(db_path):
+    """Create a SQLite database that lacks opencode's session tables."""
+    conn = sqlite3.connect(str(db_path))
+    conn.execute("CREATE TABLE migrations (id INTEGER PRIMARY KEY, name TEXT)")
+    conn.commit()
+    conn.close()
+
+
 def _make_opencode_parser(base_dir, max_age_days=0):
     """Build an OpencodeParser whose backend detection points at base_dir."""
     with patch.object(OpencodeParser, "_candidate_base_dirs", return_value=[base_dir]):
@@ -2132,7 +2140,7 @@ def test_no_backend_found(self, tmp_path):
         assert parser.parse_all() == []
 
     def test_sqlite_backend_detected(self, tmp_path):
-        (tmp_path / "opencode.db").touch()
+        _build_opencode_db(tmp_path / "opencode.db", [], [], [])
         parser = _make_opencode_parser(tmp_path)
         assert parser.backend == "sqlite"
 
@@ -2142,37 +2150,102 @@ def test_json_backend_detected(self, tmp_path):
         assert parser.backend == "json"
 
     def test_sqlite_takes_priority_over_json(self, tmp_path):
-        (tmp_path / "opencode.db").touch()
+        _build_opencode_db(tmp_path / "opencode.db", [], [], [])
         (tmp_path / "storage").mkdir()
         parser = _make_opencode_parser(tmp_path)
         assert parser.backend == "sqlite"
 
     def test_channel_suffixed_db_detected(self, tmp_path):
         """Non-stable channels write opencode-<channel>.db instead."""
-        (tmp_path / "opencode-nightly.db").touch()
+        _build_opencode_db(tmp_path / "opencode-nightly.db", [], [], [])
         parser = _make_opencode_parser(tmp_path)
         assert parser.backend == "sqlite"
         assert parser.db_path.name == "opencode-nightly.db"
 
     def test_default_db_preferred_over_channel_suffixed(self, tmp_path):
-        (tmp_path / "opencode.db").touch()
-        (tmp_path / "opencode-dev.db").touch()
+        _build_opencode_db(tmp_path / "opencode.db", [], [], [])
+        _build_opencode_db(tmp_path / "opencode-dev.db", [], [], [])
         parser = _make_opencode_parser(tmp_path)
         assert parser.db_path.name == "opencode.db"
 
     def test_opencode_db_env_override(self, tmp_path, monkeypatch):
         custom = tmp_path / "custom.db"
-        custom.touch()
+        _build_opencode_db(custom, [], [], [])
         monkeypatch.setenv("OPENCODE_DB", str(custom))
         parser = _make_opencode_parser(tmp_path)
         assert parser.db_path == custom
 
     def test_opencode_db_memory_value_ignored(self, tmp_path, monkeypatch):
         monkeypatch.setenv("OPENCODE_DB", ":memory:")
+        _build_opencode_db(tmp_path / "opencode.db", [], [], [])
+        parser = _make_opencode_parser(tmp_path)
+        assert parser.db_path.name == "opencode.db"
+
+    def test_channel_db_selected_when_default_lacks_tables(self, tmp_path):
+        """An empty or migration-only opencode.db must not shadow a populated channel DB."""
+        _build_non_opencode_db(tmp_path / "opencode.db")
+        _build_opencode_db(tmp_path / "opencode-nightly.db", [], [], [])
+        parser = _make_opencode_parser(tmp_path)
+        assert parser.backend == "sqlite"
+        assert parser.db_path.name == "opencode-nightly.db"
+
+    def test_db_without_session_tables_falls_back_to_json(self, tmp_path):
+        _build_non_opencode_db(tmp_path / "opencode.db")
+        (tmp_path / "storage").mkdir()
+        parser = _make_opencode_parser(tmp_path)
+        assert parser.backend == "json"
+        assert parser.db_path is None
+        parser.reset_diagnostics()
+        parser.parse_all()
+        assert "unsupported_schema" not in parser.get_diagnostics()
+
+    def test_db_without_session_tables_and_no_json_reports_unsupported_schema(self, tmp_path):
+        _build_non_opencode_db(tmp_path / "opencode.db")
+        parser = _make_opencode_parser(tmp_path)
+        assert parser.backend is None
+        parser.reset_diagnostics()
+        assert parser.parse_all() == []
+        assert parser.get_diagnostics() == {"unsupported_schema": 1}
+
+    def test_empty_db_file_is_not_selected(self, tmp_path):
         (tmp_path / "opencode.db").touch()
         parser = _make_opencode_parser(tmp_path)
+        assert parser.backend is None
+
+    def test_env_override_without_tables_falls_through_to_default(self, tmp_path, monkeypatch):
+        _build_non_opencode_db(tmp_path / "custom.db")
+        _build_opencode_db(tmp_path / "opencode.db", [], [], [])
+        monkeypatch.setenv("OPENCODE_DB", "custom.db")
+        parser = _make_opencode_parser(tmp_path)
         assert parser.db_path.name == "opencode.db"
 
+    def test_unreadable_candidate_is_skipped(self, tmp_path):
+        _build_opencode_db(tmp_path / "opencode.db", [], [], [])
+        _build_opencode_db(tmp_path / "opencode-dev.db", [], [], [])
+        real_connect = sqlite3.connect
+
+        def flaky_connect(target, *args, **kwargs):
+            if "opencode.db" in str(target):
+                raise sqlite3.OperationalError("unable to open database file")
+            return real_connect(target, *args, **kwargs)
+
+        with patch("adr_sensor.parsers.opencode_parser.sqlite3.connect", side_effect=flaky_connect):
+            parser = _make_opencode_parser(tmp_path)
+        assert parser.db_path.name == "opencode-dev.db"
+
+    def test_find_db_files_lists_candidates_in_priority_order(self, tmp_path, monkeypatch):
+        for name in ("opencode-nightly.db", "opencode-beta.db", "opencode.db", "custom.db"):
+            (tmp_path / name).touch()
+        monkeypatch.setenv("OPENCODE_DB", "custom.db")
+        names = [p.name for p in OpencodeParser._find_db_files(tmp_path)]
+        assert names == ["custom.db", "opencode.db", "opencode-beta.db", "opencode-nightly.db"]
+        assert OpencodeParser._find_db_file(tmp_path).name == "custom.db"
+
+    def test_find_db_files_does_not_repeat_env_override(self, tmp_path, monkeypatch):
+        (tmp_path / "opencode.db").touch()
+        monkeypatch.setenv("OPENCODE_DB", "opencode.db")
+        assert OpencodeParser._find_db_files(tmp_path) == [tmp_path / "opencode.db"]
+
     def test_xdg_data_home_is_first_candidate(self, tmp_path, monkeypatch):
         monkeypatch.setenv("XDG_DATA_HOME", str(tmp_path))
         assert OpencodeParser._candidate_base_dirs()[0] == tmp_path / "opencode"
@@ -2182,6 +2255,28 @@ def test_default_max_age_days(self):
 
 
 class TestOpencodeParserSqlite:
+    def test_missing_table_during_parse_records_unsupported_schema(self, tmp_path):
+        db_path = tmp_path / "opencode.db"
+        conn = sqlite3.connect(str(db_path))
+        conn.execute("CREATE TABLE session (id TEXT PRIMARY KEY, time_updated INTEGER)")
+        conn.execute("INSERT INTO session VALUES ('ses_1', ?)", (NOW_MS,))
+        conn.commit()
+        conn.close()
+        parser = _make_opencode_parser(tmp_path)
+        parser.reset_diagnostics()
+        assert parser._parse_sqlite(db_path) == []
+        diagnostics = parser.get_diagnostics()
+        assert diagnostics.get("unsupported_schema") == 1
+        assert "database_error" not in diagnostics
+
+    def test_unreadable_database_still_records_database_error(self, tmp_path):
+        db_path = tmp_path / "opencode.db"
+        db_path.write_bytes(b"not a sqlite database" * 10)
+        parser = _make_opencode_parser(tmp_path)
+        parser.reset_diagnostics()
+        assert parser._parse_sqlite(db_path) == []
+        assert parser.get_diagnostics() == {"database_error": 1}
+
     def test_parses_conversation_with_tool(self, tmp_path):
         db_path = tmp_path / "opencode.db"
         _build_opencode_db(