[codex] fix mt5 adapter APIs (#36)

* fix mt5 adapter APIs

* address PR feedback

* fix zero ratio minimum volume sizing

* Bump version to v0.8.0

README.md

@@ -85,6 +85,37 @@ Schema contracts live in `mt5cli.schemas` (`DataKind`, `validate_schema`, `norma
 
 `MT5Client.order_send()` is a live execution primitive: it can place real trades on the connected account. mt5cli does not implement strategy logic, signal generation, backtesting, or optimization — downstream applications must gate live execution explicitly.
 
+### Trading lifecycle and state helpers
+
+Trading applications can depend on `mt5cli` imports only; terminal path,
+credentials, server, and timeout are forwarded to `pdmt5.Mt5Config`, numeric
+login strings are coerced to integers, and empty login strings are treated as
+unset.
+
+```python
+from mt5cli import (
+    calculate_spread_ratio,
+    create_trading_client,
+    get_account_snapshot,
+    mt5_trading_session,
+)
+
+with mt5_trading_session(
+    path=r"C:\Program Files\MetaTrader 5\terminal64.exe",
+    login="12345",
+    password="from-env-or-secret-store",
+    server="Broker-Demo",
+) as client:
+    account = get_account_snapshot(client)
+    spread = calculate_spread_ratio(client, "EURUSD")
+
+client = create_trading_client(login=12345, server="Broker-Demo")
+try:
+    positions = client.positions_get_as_df(symbol="EURUSD")
+finally:
+    client.shutdown()
+```
+
 ## CLI usage
 
 ```bash

docs/api/history.md

@@ -167,19 +167,45 @@ Resolution rules:
 
 ### Rate data loading
 
-Use `load_rate_data()` to load a table or view from a SQLite path, or
+The canonical normalized rate table is `rates`; compatibility views are named
-`load_rate_data_from_connection()` when you already have a connection:
+with `rate_<symbol>__<timeframe>` for single-timeframe symbols or
+`rate_<symbol>__<granularity>_<timeframe>` when a symbol has multiple stored
+timeframes. `resolve_rate_table_name()` returns `rates`, while
+`resolve_rate_view_name()` returns the per-symbol compatibility view name.
+
+Use `load_rate_data()` or `load_rate_series_from_sqlite(..., table=...)` to load
+a single table or view from a SQLite path. Use
+`load_rate_series_by_granularity()` to load multiple instrument/granularity
+targets without hard-coding view names:
 
 ```python
 from pathlib import Path
 
-from mt5cli import load_rate_data
+from mt5cli import (
+    load_rate_data,
+    load_rate_series_by_granularity,
+    load_rate_series_from_sqlite,
+    resolve_rate_table_name,
+)
 from mt5cli.history import resolve_rate_view_name
 
 view = resolve_rate_view_name(Path("history.db"), "EURUSD", "M1", require_existing=True)
 rates = load_rate_data(Path("history.db"), view, count=1000)
+same_rates = load_rate_series_from_sqlite(Path("history.db"), table=view, count=1000)
+
+table = resolve_rate_table_name("EURUSD", "M1")  # "rates"
+series = load_rate_series_by_granularity(
+    Path("history.db"),
+    symbols=["EURUSD", "GBPUSD"],
+    granularities=["M1", "H1"],
+    count=500,
+)
 ```
 
+`count` returns the latest rows while preserving chronological order. Missing
+tables/views and mismatched `explicit_tables` lengths raise `ValueError` with
+the requested database target in the message.
+
 The loader accepts close-based OHLC rate data or tick-like bid/ask data. It
 validates that `time` exists, parses timestamps with pandas, and returns a
 DataFrame indexed by ascending `DatetimeIndex` named `time`.

docs/api/sdk.md

@@ -31,13 +31,25 @@ rates = collect_latest_rates_for_accounts_with_retries(
 ### Latest closed rate bars
 
 MetaTrader 5 `start_pos=0` includes the still-forming current bar as the last
-row. `collect_latest_closed_rates_for_accounts()` fetches `count + 1` bars,
+row. `fetch_latest_closed_rates()` handles one connected client; multi-account
-drops that row with `drop_forming_rate_bar()`, and validates each series is
+helpers fetch `count + 1` bars, drop that row with `drop_forming_rate_bar()`,
-non-empty. Use `collect_latest_closed_rates_by_granularity()` when callers
+and validate each series is non-empty. Returned frames are ordered
-prefer keys such as `("EURUSD", "M1")` instead of integer timeframes.
+oldest-to-newest and may contain fewer than `count` rows only when MT5 returns
+fewer closed bars.
 
 ```python
-from mt5cli import AccountSpec, collect_latest_closed_rates_by_granularity
+from mt5cli import (
+    AccountSpec,
+    collect_latest_closed_rates_by_granularity,
+    fetch_latest_closed_rates,
+)
+
+closed = fetch_latest_closed_rates(
+    client,
+    symbol="EURUSD",
+    granularity="M1",
+    count=500,
+)
 
 rates = collect_latest_closed_rates_by_granularity(
     [AccountSpec(symbols=["EURUSD"], login=12345)],
@@ -48,6 +60,9 @@ rates = collect_latest_closed_rates_by_granularity(
 closed_m1 = rates["EURUSD", "M1"]
 ```
 
+Use `collect_latest_closed_rates_by_granularity()` when callers prefer keys such
+as `("EURUSD", "M1")` instead of integer timeframes.
+
 ### Resolving credentials and `${ENV_VAR}` placeholders
 
 `resolve_account_spec()` / `resolve_account_specs()` merge explicit override

docs/api/trading.md

@@ -4,38 +4,60 @@
 
 ## Trading-capable MT5 sessions
 
-`mt5_trading_session()` complements the read-only `mt5_session()` helper in
+`create_trading_client()` and `mt5_trading_session()` complement the read-only
-`sdk.py`. It yields a connected `pdmt5.Mt5TradingClient`, uses
+`mt5_session()` helper in `sdk.py`. They return or yield an initialized
-`Mt5Config.path` to launch the terminal when configured, and always calls
+`pdmt5.Mt5TradingClient`, use `Mt5Config.path` to launch the terminal when
-`shutdown()` on exit.
+configured, and `mt5_trading_session()` always calls `shutdown()` on exit.
 
 ```python
-from pdmt5 import Mt5Config
+from mt5cli import create_trading_client, mt5_trading_session
-
-from mt5cli import mt5_trading_session
 
 with mt5_trading_session(
-    Mt5Config(path=r"C:\Program Files\MetaTrader 5\terminal64.exe", login=12345),
+    path=r"C:\Program Files\MetaTrader 5\terminal64.exe",
+    login="12345",
+    password="secret",
+    server="Broker-Demo",
     retry_count=2,
 ) as client:
     positions = client.positions_get_as_df(symbol="EURUSD")
+
+client = create_trading_client(login=12345, server="Broker-Demo")
+try:
+    account = client.account_info_as_dict()
+finally:
+    client.shutdown()
 ```
 
+`login` accepts `int`, numeric `str`, or an empty string; empty strings are
+treated as unset. `path`, `password`, `server`, and `timeout` are forwarded to
+`pdmt5.Mt5Config`, and omitted `timeout` values keep the lower-level default.
 The read-only `Mt5CliClient` / `mt5_session()` API is unchanged.
 
-## Operational trading helpers
+## State and order helpers
 
 These helpers are strategy-agnostic and do not depend on signal detection,
 betting logic, or scheduling code in downstream applications.
 
 ```python
 from mt5cli import (
+    calculate_spread_ratio,
     calculate_margin_and_volume,
+    close_open_positions,
     detect_position_side,
     determine_order_limits,
+    get_account_snapshot,
+    get_positions_frame,
+    get_symbol_snapshot,
+    get_tick_snapshot,
+    place_market_order,
 )
 
+account = get_account_snapshot(client)
+symbol = get_symbol_snapshot(client, "EURUSD")
+tick = get_tick_snapshot(client, "EURUSD")
+positions = get_positions_frame(client, "EURUSD")
 side = detect_position_side(client, "EURUSD")
+spread_ratio = calculate_spread_ratio(client, "EURUSD")
 sizing = calculate_margin_and_volume(
     client,
     "EURUSD",
@@ -49,11 +71,33 @@ limits = determine_order_limits(
     stop_loss_limit_ratio=0.01,
     take_profit_limit_ratio=0.02,
 )
+preview = place_market_order(
+    client,
+    symbol="EURUSD",
+    volume=sizing["buy_volume"],
+    order_side="BUY",
+    sl=limits["stop_loss"],
+    tp=limits["take_profit"],
+    dry_run=True,
+)
+closed = close_open_positions(client, symbols="EURUSD", dry_run=True)
 ```
 
-Protective ratios must satisfy `0 <= ratio < 1`; `0` omits that level.
+`detect_position_side()` returns `long` for buy-only exposure, `short` for
-`calculate_margin_and_volume()` clamps negative `margin_free` to `0.0`
+sell-only exposure, and `None` for no positions or mixed long/short exposure.
-before sizing.
+`calculate_spread_ratio()` uses `(ask - bid) / ((ask + bid) / 2)` and raises
+`Mt5TradingError` when bid or ask is missing or non-positive.
+
+SL/TP ratios for `determine_order_limits()` must satisfy `0 <= ratio < 1`; `0`
+omits that level. SL/TP prices are rounded with symbol `digits` metadata when
+available. `unit_margin_ratio` and `preserved_margin_ratio` for
+`calculate_margin_and_volume()` accept `0 <= ratio <= 1`; `unit_margin_ratio=0`
+requests one minimum valid unit when the post-reserve margin can afford it.
+Negative `margin_free` is clamped to `0.0` before sizing. Execution helpers
+return normalized dictionaries containing the request, response, status,
+retcode, and `dry_run` flag; `dry_run=True` never sends an order. Market order
+helpers mark known non-success MT5 retcodes as `status="failed"` while keeping
+the normalized response for inspection.
 
 ## Migration from mteor-local helpers
 

mt5cli/__init__.py

@@ -2,6 +2,8 @@
 
 from importlib.metadata import version
 
+from pdmt5 import Mt5Config, Mt5RuntimeError, Mt5TradingClient, Mt5TradingError
+
 from .client import MT5Client, build_config, mt5_session
 from .converters import (
     ensure_utc,
@@ -32,6 +34,7 @@ from .history import (
     resolve_history_datasets,
     resolve_history_tick_flags,
     resolve_history_timeframes,
+    resolve_rate_table_name,
     resolve_rate_tables,
     resolve_rate_view_name,
     resolve_rate_view_names,
@@ -63,6 +66,7 @@ from .sdk import (
     copy_rates_range,
     copy_ticks_from,
     copy_ticks_range,
+    fetch_latest_closed_rates,
     history_deals,
     history_orders,
     last_error,
@@ -96,10 +100,26 @@ from .storage import (
     export_dataframe_to_sqlite,
 )
 from .trading import (
+    POSITION_COLUMNS,
+    OrderFillingMode,
+    OrderSide,
+    OrderTimeMode,
+    PositionSide,
     calculate_margin_and_volume,
+    calculate_new_position_margin_ratio,
+    calculate_spread_ratio,
+    calculate_volume_by_margin,
+    close_open_positions,
+    create_trading_client,
     detect_position_side,
     determine_order_limits,
+    get_account_snapshot,
+    get_positions_frame,
+    get_symbol_snapshot,
+    get_tick_snapshot,
     mt5_trading_session,
+    place_market_order,
+    update_sltp_for_open_positions,
 )
 from .utils import (
     TICK_FLAG_MAP,
@@ -114,6 +134,7 @@ __version__ = version(__package__) if __package__ else None
 __all__ = [
     "DEDUP_KEYS",
     "KNOWN_MT5_TIME_COLUMNS",
+    "POSITION_COLUMNS",
     "REQUIRED_COLUMNS",
     "TICK_FLAG_MAP",
     "TIMEFRAME_MAP",
@@ -125,9 +146,17 @@ __all__ = [
     "MT5Client",
     "Mt5CliClient",
     "Mt5CliError",
+    "Mt5Config",
     "Mt5ConnectionError",
     "Mt5OperationError",
+    "Mt5RuntimeError",
     "Mt5SchemaError",
+    "Mt5TradingClient",
+    "Mt5TradingError",
+    "OrderFillingMode",
+    "OrderSide",
+    "OrderTimeMode",
+    "PositionSide",
     "RateTarget",
     "ThrottledHistoryUpdater",
     "account_info",
@@ -135,7 +164,11 @@ __all__ = [
     "build_rate_targets",
     "build_rate_view_name",
     "calculate_margin_and_volume",
+    "calculate_new_position_margin_ratio",
+    "calculate_spread_ratio",
+    "calculate_volume_by_margin",
     "call_with_normalized_errors",
+    "close_open_positions",
     "collect_history",
     "collect_latest_closed_rates_by_granularity",
     "collect_latest_closed_rates_for_accounts",
@@ -147,6 +180,7 @@ __all__ = [
     "copy_rates_range",
     "copy_ticks_from",
     "copy_ticks_range",
+    "create_trading_client",
     "detect_format",
     "detect_position_side",
     "determine_order_limits",
@@ -154,6 +188,11 @@ __all__ = [
     "ensure_utc",
     "export_dataframe",
     "export_dataframe_to_sqlite",
+    "fetch_latest_closed_rates",
+    "get_account_snapshot",
+    "get_positions_frame",
+    "get_symbol_snapshot",
+    "get_tick_snapshot",
     "granularity_name",
     "history_deals",
     "history_orders",
@@ -181,6 +220,7 @@ __all__ = [
     "parse_datetime",
     "parse_tick_flags",
     "parse_timeframe",
+    "place_market_order",
     "positions",
     "recent_history_deals",
     "recent_ticks",
@@ -190,6 +230,7 @@ __all__ = [
     "resolve_history_datasets",
     "resolve_history_tick_flags",
     "resolve_history_timeframes",
+    "resolve_rate_table_name",
     "resolve_rate_tables",
     "resolve_rate_view_name",
     "resolve_rate_view_names",
@@ -201,5 +242,6 @@ __all__ = [
     "terminal_info",
     "update_history",
     "update_history_with_config",
+    "update_sltp_for_open_positions",
     "validate_schema",
 ]

mt5cli/history.py

@@ -7,7 +7,7 @@ import sqlite3
 from dataclasses import dataclass
 from datetime import UTC, datetime
 from pathlib import Path
-from typing import TYPE_CHECKING, Literal, cast
+from typing import TYPE_CHECKING, Literal, cast, overload
 
 import pandas as pd
 from pdmt5 import get_timeframe_name as _get_timeframe_name
@@ -142,6 +142,26 @@ def build_rate_view_name(
     return f"rate_{symbol}__{granularity}_{timeframe}"
 
 
+def resolve_rate_table_name(symbol: str, granularity: str) -> str:
+    """Return the canonical normalized SQLite rate table name.
+
+    The normalized history table stores all symbols and timeframes in
+    ``rates``; use :func:`resolve_rate_view_name` for per-symbol compatibility
+    view names.
+
+    Returns:
+        Canonical normalized rates table name.
+
+    Raises:
+        ValueError: If ``symbol`` or ``granularity`` is invalid.
+    """
+    parse_timeframe(granularity)
+    if not symbol.strip():
+        msg = "symbol must not be empty."
+        raise ValueError(msg)
+    return Dataset.rates.table_name
+
+
 SqliteConnOrPath = sqlite3.Connection | Path | str
 
 
@@ -653,34 +673,76 @@ def resolve_rate_tables(
             conn.close()
 
 
+if TYPE_CHECKING:
+
+    @overload
+    def load_rate_series_from_sqlite(
+        conn_or_path: SqliteConnOrPath,
+        targets: None = None,
+        count: int | None = None,
+        explicit_tables: None = None,
+        *,
+        table: str,
+    ) -> pd.DataFrame: ...
+
+    @overload
+    def load_rate_series_from_sqlite(
+        conn_or_path: SqliteConnOrPath,
+        targets: None = None,
+        count: int | None = None,
+        explicit_tables: Sequence[str] | None = None,
+        *,
+        table: None = None,
+    ) -> dict[tuple[str | None, int], pd.DataFrame]: ...
+
+    @overload
+    def load_rate_series_from_sqlite(
+        conn_or_path: SqliteConnOrPath,
+        targets: Sequence[RateTarget],
+        count: int,
+        explicit_tables: Sequence[str] | None = None,
+        *,
+        table: None = None,
+    ) -> dict[tuple[str | None, int], pd.DataFrame]: ...
+
+
 def load_rate_series_from_sqlite(
     conn_or_path: SqliteConnOrPath,
-    targets: Sequence[RateTarget],
+    targets: Sequence[RateTarget] | None = None,
-    count: int,
+    count: int | None = None,
     explicit_tables: Sequence[str] | None = None,
-) -> dict[tuple[str | None, int], pd.DataFrame]:
+    *,
-    """Load multiple rate series from a SQLite database.
+    table: str | None = None,
+) -> dict[tuple[str | None, int], pd.DataFrame] | pd.DataFrame:
+    """Load one table/view or multiple rate series from a SQLite database.
 
     Args:
         conn_or_path: SQLite database path or open connection.
-        targets: Rate targets to load. Each ``(symbol, timeframe_int)`` pair
+        targets: Rate targets to load. Each ``(symbol, timeframe_int)`` pair must
-            must be unique.
+            be unique. Omit when loading a single explicit ``table``.
-        count: Number of most recent rows to load per series.
+        count: Optional number of most recent rows to load per series.
         explicit_tables: Optional explicit table or view names matching targets.
             When omitted, managed ``rate_*`` compatibility views must already
             exist in the database.
+        table: Optional single table or view name to load directly.
 
     Returns:
-        Mapping keyed by ``(symbol, timeframe_int)`` to each rate DataFrame.
+        A DataFrame when ``table`` is provided, otherwise a mapping keyed by
+        ``(symbol, timeframe_int)`` to each rate DataFrame.
 
     Raises:
         ValueError: If ``count`` is not positive, targets are empty, duplicate
             ``(symbol, timeframe_int)`` pairs are present, or table resolution
             fails.
     """
-    if count <= 0:
+    if table is not None:
+        return load_rate_data(conn_or_path, table, count=count)
+    if count is None or count <= 0:
         msg = "count must be positive."
         raise ValueError(msg)
+    if targets is None:
+        msg = "targets are required when table is not provided."
+        raise ValueError(msg)
     target_list = list(targets)
     if not target_list:
         msg = "At least one rate target is required."

mt5cli/sdk.py

@@ -37,6 +37,7 @@ from .utils import (
     parse_tick_flags,
     parse_timeframe,
 )
+from .utils import coerce_login as _coerce_login
 
 if TYPE_CHECKING:
     from collections.abc import Callable, Iterator, Sequence
@@ -122,6 +123,7 @@ __all__ = [
     "copy_rates_range",
     "copy_ticks_from",
     "copy_ticks_range",
+    "fetch_latest_closed_rates",
     "history_deals",
     "history_orders",
     "last_error",
@@ -1289,6 +1291,33 @@ def latest_rates(
     )
 
 
+def fetch_latest_closed_rates(
+    client: Mt5CliClient,
+    *,
+    symbol: str,
+    granularity: str,
+    count: int,
+) -> pd.DataFrame:
+    """Fetch up to ``count`` most recent closed bars, oldest to newest.
+
+    Returns:
+        Closed rate bars ordered oldest to newest.
+
+    Raises:
+        ValueError: If ``count`` is not positive or no closed bars are returned.
+    """
+    _require_positive(count, "count")
+    frame = client.latest_rates(symbol, granularity, count + 1, start_pos=0)
+    closed = drop_forming_rate_bar(frame)
+    if closed.empty:
+        msg = (
+            f"Rate data is empty for {symbol!r} at granularity {granularity!r} "
+            f"with count {count}."
+        )
+        raise ValueError(msg)
+    return closed.tail(count).reset_index(drop=True)
+
+
 def collect_latest_rates(
     symbols: Sequence[str],
     timeframes: Sequence[int | str],
@@ -1470,20 +1499,6 @@ def resolve_account_specs(
     ]
 
 
-def _coerce_login(login: int | str | None) -> int | None:
-    """Coerce a login value to int, treating empty strings as unset.
-
-    Returns:
-        Integer login, or None when unset or an empty string.
-    """
-    if login is None or isinstance(login, int):
-        return login
-    text = login.strip()
-    if not text:
-        return None
-    return int(text)
-
-
 def _build_account_config(
     account: AccountSpec,
     base_config: Mt5Config | None,

mt5cli/trading.py

@@ -3,27 +3,98 @@
 from __future__ import annotations
 
 from contextlib import contextmanager
-from typing import TYPE_CHECKING, Literal
+from math import floor, isfinite
+from typing import TYPE_CHECKING, Literal, cast
 
-from pdmt5 import Mt5Config, Mt5TradingClient
+import pandas as pd
+from pdmt5 import Mt5Config, Mt5TradingClient, Mt5TradingError
 
 from .sdk import build_config
+from .utils import coerce_login as _coerce_login
 
 if TYPE_CHECKING:
     from collections.abc import Iterator
 
-    import pandas as pd
-
 PositionSide = Literal["long", "short"]
-OrderSide = Literal["long", "short"]
+OrderSide = Literal["BUY", "SELL"]
+OrderFillingMode = Literal["IOC", "FOK", "RETURN"]
+OrderTimeMode = Literal["GTC", "DAY", "SPECIFIED", "SPECIFIED_DAY"]
+_ORDER_FILLING_MODES: frozenset[str] = frozenset({"IOC", "FOK", "RETURN"})
+_ORDER_TIME_MODES: frozenset[str] = frozenset({
+    "GTC",
+    "DAY",
+    "SPECIFIED",
+    "SPECIFIED_DAY",
+})
+_SUCCESS_RETCODE_NAMES: tuple[str, ...] = (
+    "TRADE_RETCODE_DONE",
+    "TRADE_RETCODE_DONE_PARTIAL",
+    "TRADE_RETCODE_PLACED",
+)
+_SUCCESS_RETCODE_FALLBACKS: frozenset[int] = frozenset({10008, 10009, 10010})
+
+_ACCOUNT_SNAPSHOT_FIELDS = (
+    "login",
+    "balance",
+    "equity",
+    "margin",
+    "margin_free",
+    "margin_level",
+    "leverage",
+    "currency",
+)
+_SYMBOL_SNAPSHOT_FIELDS = (
+    "symbol",
+    "visible",
+    "trade_mode",
+    "digits",
+    "point",
+    "volume_min",
+    "volume_max",
+    "volume_step",
+    "trade_contract_size",
+    "trade_tick_size",
+    "trade_tick_value",
+    "trade_stops_level",
+    "filling_mode",
+)
+_TICK_SNAPSHOT_FIELDS = ("symbol", "time", "bid", "ask", "last", "volume")
+POSITION_COLUMNS = (
+    "ticket",
+    "time",
+    "symbol",
+    "type",
+    "volume",
+    "price_open",
+    "sl",
+    "tp",
+    "price_current",
+    "profit",
+    "swap",
+    "comment",
+)
 
 __all__ = [
+    "POSITION_COLUMNS",
+    "OrderFillingMode",
     "OrderSide",
+    "OrderTimeMode",
     "PositionSide",
     "calculate_margin_and_volume",
+    "calculate_new_position_margin_ratio",
+    "calculate_spread_ratio",
+    "calculate_volume_by_margin",
+    "close_open_positions",
+    "create_trading_client",
     "detect_position_side",
     "determine_order_limits",
+    "get_account_snapshot",
+    "get_positions_frame",
+    "get_symbol_snapshot",
+    "get_tick_snapshot",
     "mt5_trading_session",
+    "place_market_order",
+    "update_sltp_for_open_positions",
 ]
 
 
@@ -46,18 +117,184 @@ def _sum_position_volume(positions: pd.DataFrame, position_type: object) -> floa
     return float(matched.to_numpy(dtype=float).sum())
 
 
+def _resolve_config(
+    *,
+    config: Mt5Config | None,
+    login: int | str | None,
+    password: str | None,
+    server: str | None,
+    path: str | None,
+    timeout: int | None,
+) -> Mt5Config:
+    if config is not None:
+        return config
+    return build_config(
+        path=path,
+        login=_coerce_login(login),
+        password=password,
+        server=server,
+        timeout=timeout,
+    )
+
+
 def _normalize_order_side(side: str) -> OrderSide:
+    normalized = side.upper()
+    if normalized in {"BUY", "LONG"}:
+        return "BUY"
+    if normalized in {"SELL", "SHORT"}:
+        return "SELL"
+    msg = f"Unsupported order side: {side!r}. Expected 'BUY' or 'SELL'."
+    raise ValueError(msg)
+
+
+def _position_side_from_order_side(side: str) -> PositionSide:
     normalized = side.lower()
     if normalized in {"long", "buy"}:
         return "long"
     if normalized in {"short", "sell"}:
         return "short"
-    msg = (
+    msg = f"Unsupported position side: {side!r}. Expected 'long' or 'short'."
-        f"Unsupported order side: {side!r}. Expected 'long', 'short', 'buy', or 'sell'."
-    )
     raise ValueError(msg)
 
 
+def _snapshot_from_value(value: object, fields: tuple[str, ...]) -> dict[str, object]:
+    if isinstance(value, pd.DataFrame):
+        row: dict[str, object] = (
+            {} if value.empty else cast("dict[str, object]", value.iloc[0].to_dict())
+        )
+    else:
+        asdict = getattr(value, "_asdict", None)
+        if callable(asdict):
+            row = cast("dict[str, object]", asdict())
+        elif isinstance(value, dict):
+            typed_value = cast("dict[object, object]", value)
+            row = {str(key): item for key, item in typed_value.items()}
+        else:
+            row = {
+                field: getattr(value, field)
+                for field in fields
+                if hasattr(value, field)
+            }
+    if not fields:
+        return row
+    return {field: row.get(field) for field in fields}
+
+
+def _call_snapshot_method(client: Mt5TradingClient, *names: str) -> object:
+    for name in names:
+        method = getattr(client, name, None)
+        if callable(method):
+            return method()
+    msg = f"MT5 client is missing required method: {' or '.join(names)}"
+    raise AttributeError(msg)
+
+
+def _resolve_mt5_constant(
+    mt5: object,
+    prefix: str,
+    value: str,
+    allowed: frozenset[str],
+) -> int:
+    normalized = value.upper()
+    if normalized not in allowed:
+        msg = f"Unsupported {prefix.lower()} mode: {value!r}."
+        raise ValueError(msg)
+    name = f"{prefix}_{normalized}"
+    try:
+        return cast("int", getattr(mt5, name))
+    except AttributeError as exc:
+        msg = f"MT5 module is missing required constant: {name}"
+        raise Mt5TradingError(msg) from exc
+
+
+def _optional_price(value: object) -> float | None:
+    if value is None:
+        return None
+    if not isinstance(value, int | float):
+        return None
+    price = float(value)
+    if price <= 0 or not isfinite(price):
+        return None
+    return price
+
+
+def _success_retcodes(mt5: object) -> frozenset[int]:
+    values = {
+        value
+        for name in _SUCCESS_RETCODE_NAMES
+        if isinstance(value := getattr(mt5, name, None), int)
+    }
+    return frozenset(values) or _SUCCESS_RETCODE_FALLBACKS
+
+
+def _order_status_from_retcode(mt5: object, retcode: object) -> str:
+    if retcode is None:
+        return "executed"
+    if isinstance(retcode, int) and retcode not in _success_retcodes(mt5):
+        return "failed"
+    return "executed"
+
+
+def _calculate_min_volume_if_affordable(
+    client: Mt5TradingClient,
+    symbol: str,
+    available_margin: float,
+    order_side: OrderSide,
+) -> float:
+    if available_margin <= 0:
+        return 0.0
+    symbol_info = get_symbol_snapshot(client, symbol)
+    volume_min = float(symbol_info.get("volume_min") or 0.0)
+    volume_max = float(symbol_info.get("volume_max") or 0.0)
+    volume_step = float(symbol_info.get("volume_step") or volume_min or 0.0)
+    if (
+        volume_min <= 0
+        or volume_step <= 0
+        or (volume_max > 0 and volume_min > volume_max)
+    ):
+        msg = f"Invalid volume constraints for {symbol!r}."
+        raise Mt5TradingError(msg)
+    side = _normalize_order_side(order_side)
+    tick = get_tick_snapshot(client, symbol)
+    price = tick["ask"] if side == "BUY" else tick["bid"]
+    if not isinstance(price, int | float) or price <= 0:
+        msg = f"Tick price is unavailable for {symbol!r}."
+        raise Mt5TradingError(msg)
+    order_type = (
+        client.mt5.ORDER_TYPE_BUY if side == "BUY" else client.mt5.ORDER_TYPE_SELL
+    )
+    min_margin = float(client.order_calc_margin(order_type, symbol, volume_min, price))
+    return round(volume_min, 10) if 0 < min_margin <= available_margin else 0.0
+
+
+def create_trading_client(
+    *,
+    config: Mt5Config | None = None,
+    login: int | str | None = None,
+    password: str | None = None,
+    server: str | None = None,
+    path: str | None = None,
+    timeout: int | None = None,
+    retry_count: int = 0,
+) -> Mt5TradingClient:
+    """Return an initialized and logged-in trading client."""
+    mt5_config = _resolve_config(
+        config=config,
+        login=login,
+        password=password,
+        server=server,
+        path=path,
+        timeout=timeout,
+    )
+    client = Mt5TradingClient(config=mt5_config, retry_count=retry_count)
+    try:
+        client.initialize_and_login_mt5()
+    except Exception:
+        client.shutdown()
+        raise
+    return client
+
+
 def detect_position_side(
     client: Mt5TradingClient,
     symbol: str,
@@ -69,11 +306,11 @@ def detect_position_side(
         symbol: Symbol to inspect.
 
     Returns:
-        ``"long"`` when net buy volume exceeds sell volume, ``"short"`` when
+        ``"long"`` when there are buy positions and no sell positions,
-        net sell volume exceeds buy volume, or ``None`` when no positions exist
+        ``"short"`` when there are sell positions and no buy positions, or
-        or buy/sell volumes are exactly balanced.
+        ``None`` when no positions or mixed exposure exists.
     """
-    positions = client.positions_get_as_df(symbol=symbol)
+    positions = get_positions_frame(client, symbol=symbol)
     if positions.empty:
         return None
 
@@ -81,14 +318,114 @@ def detect_position_side(
     sell_type = client.mt5.POSITION_TYPE_SELL
     buy_volume = _sum_position_volume(positions, buy_type)
     sell_volume = _sum_position_volume(positions, sell_type)
-    net_volume = buy_volume - sell_volume
+    if buy_volume > 0 and sell_volume == 0:
-    if net_volume > 0:
         return "long"
-    if net_volume < 0:
+    if sell_volume > 0 and buy_volume == 0:
         return "short"
     return None
 
 
+def get_account_snapshot(
+    client: Mt5TradingClient,
+) -> dict[str, float | int | str | None]:
+    """Return normalized account state with stable keys."""
+    value = _call_snapshot_method(client, "account_info_as_dict", "account_info")
+    return cast(
+        "dict[str, float | int | str | None]",
+        _snapshot_from_value(value, _ACCOUNT_SNAPSHOT_FIELDS),
+    )
+
+
+def get_symbol_snapshot(
+    client: Mt5TradingClient,
+    symbol: str,
+) -> dict[str, float | int | str | bool | None]:
+    """Return normalized symbol metadata required for trading decisions."""
+    method = getattr(client, "symbol_info_as_dict", None)
+    value = method(symbol=symbol) if callable(method) else client.symbol_info(symbol)
+    snapshot = _snapshot_from_value(value, _SYMBOL_SNAPSHOT_FIELDS)
+    snapshot["symbol"] = snapshot.get("symbol") or symbol
+    return cast("dict[str, float | int | str | bool | None]", snapshot)
+
+
+def get_tick_snapshot(
+    client: Mt5TradingClient,
+    symbol: str,
+) -> dict[str, float | int | None]:
+    """Return normalized latest tick data, including bid, ask, and timestamp."""
+    method = getattr(client, "symbol_info_tick_as_dict", None)
+    value = (
+        method(symbol=symbol) if callable(method) else client.symbol_info_tick(symbol)
+    )
+    snapshot = _snapshot_from_value(value, _TICK_SNAPSHOT_FIELDS)
+    snapshot["symbol"] = snapshot.get("symbol") or symbol
+    return cast("dict[str, float | int | None]", snapshot)
+
+
+def get_positions_frame(
+    client: Mt5TradingClient,
+    symbol: str | None = None,
+) -> pd.DataFrame:
+    """Return open positions as a DataFrame with stable baseline columns."""
+    frame = client.positions_get_as_df(symbol=symbol)
+    for column in POSITION_COLUMNS:
+        if column not in frame.columns:
+            frame[column] = pd.Series(dtype="object")
+    return frame
+
+
+def calculate_spread_ratio(client: Mt5TradingClient, symbol: str) -> float:
+    """Return ``(ask - bid) / ((ask + bid) / 2)`` for the latest tick.
+
+    Raises:
+        Mt5TradingError: If bid or ask is unavailable or non-positive.
+    """
+    tick = get_tick_snapshot(client, symbol)
+    bid = tick.get("bid")
+    ask = tick.get("ask")
+    if not isinstance(bid, int | float) or not isinstance(ask, int | float):
+        msg = f"Tick bid/ask is unavailable for {symbol!r}."
+        raise Mt5TradingError(msg)
+    if bid <= 0 or ask <= 0:
+        msg = f"Tick bid/ask must be positive for {symbol!r}."
+        raise Mt5TradingError(msg)
+    return (float(ask) - float(bid)) / ((float(ask) + float(bid)) / 2.0)
+
+
+def calculate_new_position_margin_ratio(
+    client: Mt5TradingClient,
+    *,
+    symbol: str,
+    new_position_side: OrderSide | None = None,
+    new_position_volume: float = 0.0,
+) -> float:
+    """Return total margin/equity ratio after an optional hypothetical position.
+
+    Raises:
+        Mt5TradingError: If equity or required tick data is invalid.
+    """
+    account = get_account_snapshot(client)
+    equity = float(account.get("equity") or 0.0)
+    if equity <= 0:
+        msg = "Account equity must be positive to calculate margin ratio."
+        raise Mt5TradingError(msg)
+    margin = float(account.get("margin") or 0.0)
+    if new_position_side is not None and new_position_volume > 0:
+        side = _normalize_order_side(new_position_side)
+        tick = get_tick_snapshot(client, symbol)
+        price = tick["ask"] if side == "BUY" else tick["bid"]
+        if not isinstance(price, int | float) or price <= 0:
+            msg = f"Tick price is unavailable for {symbol!r}."
+            raise Mt5TradingError(msg)
+        order_type = (
+            client.mt5.ORDER_TYPE_BUY if side == "BUY" else client.mt5.ORDER_TYPE_SELL
+        )
+        margin += float(
+            client.order_calc_margin(order_type, symbol, new_position_volume, price),
+        )
+    return margin / equity
+
+
 def calculate_margin_and_volume(
     client: Mt5TradingClient,
     symbol: str,
@@ -99,7 +436,9 @@ def calculate_margin_and_volume(
 
     Applies ``preserved_margin_ratio`` to keep a reserve off ``margin_free``,
     then allocates ``unit_margin_ratio`` of the remainder as the margin budget
-    for volume sizing on both buy and sell sides.
+    for proportional volume sizing on both buy and sell sides. A
+    ``unit_margin_ratio`` of ``0`` requests exactly one minimum valid unit per
+    side when the post-reserve margin can afford it.
 
     Args:
         client: Connected ``Mt5TradingClient`` instance.
@@ -119,23 +458,109 @@ def calculate_margin_and_volume(
     margin_free = max(0.0, float(account.get("margin_free") or 0.0))
     available_margin = margin_free * (1.0 - preserved_margin_ratio)
     trade_margin = available_margin * unit_margin_ratio
-    buy_volume = client.calculate_volume_by_margin(symbol, trade_margin, "BUY")
+    if unit_margin_ratio == 0:
-    sell_volume = client.calculate_volume_by_margin(symbol, trade_margin, "SELL")
+        buy_volume = _calculate_min_volume_if_affordable(
+            client,
+            symbol,
+            available_margin,
+            "BUY",
+        )
+        sell_volume = _calculate_min_volume_if_affordable(
+            client,
+            symbol,
+            available_margin,
+            "SELL",
+        )
+    else:
+        native_calculate_volume = getattr(client, "calculate_volume_by_margin", None)
+        if callable(native_calculate_volume):
+            buy_volume = float(
+                cast(
+                    "float | int | str",
+                    native_calculate_volume(symbol, trade_margin, "BUY"),
+                ),
+            )
+            sell_volume = float(
+                cast(
+                    "float | int | str",
+                    native_calculate_volume(symbol, trade_margin, "SELL"),
+                ),
+            )
+        else:
+            buy_volume = calculate_volume_by_margin(client, symbol, trade_margin, "BUY")
+            sell_volume = calculate_volume_by_margin(
+                client,
+                symbol,
+                trade_margin,
+                "SELL",
+            )
+    try:
+        symbol_info = get_symbol_snapshot(client, symbol)
+        volume_min = float(symbol_info.get("volume_min") or 0.0)
+        volume_max = float(symbol_info.get("volume_max") or 0.0)
+        volume_step = float(symbol_info.get("volume_step") or 0.0)
+    except AttributeError:
+        volume_min = volume_max = volume_step = 0.0
     return {
         "margin_free": margin_free,
         "available_margin": available_margin,
         "trade_margin": trade_margin,
-        "buy_volume": buy_volume,
+        "buy_volume": float(buy_volume),
-        "sell_volume": sell_volume,
+        "sell_volume": float(sell_volume),
+        "volume_min": volume_min,
+        "volume_max": volume_max,
+        "volume_step": volume_step,
     }
 
 
+def calculate_volume_by_margin(
+    client: Mt5TradingClient,
+    symbol: str,
+    available_margin: float,
+    order_side: OrderSide,
+) -> float:
+    """Calculate max normalized volume affordable for one side.
+
+    Returns:
+        Affordable volume rounded down to symbol volume constraints.
+
+    Raises:
+        Mt5TradingError: If symbol volume constraints or tick data are invalid.
+    """
+    if available_margin <= 0:
+        return 0.0
+    symbol_info = get_symbol_snapshot(client, symbol)
+    volume_min = float(symbol_info.get("volume_min") or 0.0)
+    volume_max = float(symbol_info.get("volume_max") or 0.0)
+    volume_step = float(symbol_info.get("volume_step") or volume_min or 0.0)
+    if volume_min <= 0 or volume_step <= 0:
+        msg = f"Invalid volume constraints for {symbol!r}."
+        raise Mt5TradingError(msg)
+    side = _normalize_order_side(order_side)
+    tick = get_tick_snapshot(client, symbol)
+    price = tick["ask"] if side == "BUY" else tick["bid"]
+    if not isinstance(price, int | float) or price <= 0:
+        msg = f"Tick price is unavailable for {symbol!r}."
+        raise Mt5TradingError(msg)
+    order_type = (
+        client.mt5.ORDER_TYPE_BUY if side == "BUY" else client.mt5.ORDER_TYPE_SELL
+    )
+    min_margin = float(client.order_calc_margin(order_type, symbol, volume_min, price))
+    if min_margin <= 0 or min_margin > available_margin:
+        return 0.0
+    raw_volume = available_margin / min_margin * volume_min
+    capped = min(raw_volume, volume_max) if volume_max > 0 else raw_volume
+    steps = floor(((capped - volume_min) / volume_step) + 1e-12)
+    normalized = volume_min + max(0, steps) * volume_step
+    return round(normalized, 10) if normalized >= volume_min else 0.0
+
+
 def determine_order_limits(
     client: Mt5TradingClient,
     symbol: str,
-    side: OrderSide | str,
+    side: PositionSide | str,
-    stop_loss_limit_ratio: float,
+    stop_loss_limit_ratio: float | None = None,
-    take_profit_limit_ratio: float,
+    take_profit_limit_ratio: float | None = None,
 ) -> dict[str, float | None]:
     """Derive entry and protective order prices from current market quotes.
 
@@ -152,26 +577,41 @@ def determine_order_limits(
     Returns:
         Dictionary with ``entry``, ``stop_loss``, and ``take_profit`` keys.
         Omitted protective levels are returned as ``None``.
+
+    Raises:
+        Mt5TradingError: If required tick data is invalid.
     """
-    _require_protective_ratio(stop_loss_limit_ratio, "stop_loss_limit_ratio")
+    stop_loss_ratio = stop_loss_limit_ratio or 0.0
-    _require_protective_ratio(take_profit_limit_ratio, "take_profit_limit_ratio")
+    take_profit_ratio = take_profit_limit_ratio or 0.0
-    normalized_side = _normalize_order_side(side)
+    _require_protective_ratio(stop_loss_ratio, "stop_loss_limit_ratio")
-    tick = client.symbol_info_tick_as_dict(symbol=symbol)
+    _require_protective_ratio(take_profit_ratio, "take_profit_limit_ratio")
-    entry = float(tick["ask"] if normalized_side == "long" else tick["bid"])
+    normalized_side = _position_side_from_order_side(side)
+    tick = get_tick_snapshot(client, symbol)
+    entry_value = tick["ask"] if normalized_side == "long" else tick["bid"]
+    if not isinstance(entry_value, int | float):
+        msg = f"Tick price is unavailable for {symbol!r}."
+        raise Mt5TradingError(msg)
+    entry = float(entry_value)
+    try:
+        digits = int(get_symbol_snapshot(client, symbol).get("digits") or 8)
+    except AttributeError:
+        digits = 8
 
     stop_loss: float | None = None
-    if stop_loss_limit_ratio > 0:
+    if stop_loss_ratio > 0:
         if normalized_side == "long":
-            stop_loss = entry * (1.0 - stop_loss_limit_ratio)
+            stop_loss = entry * (1.0 - stop_loss_ratio)
         else:
-            stop_loss = entry * (1.0 + stop_loss_limit_ratio)
+            stop_loss = entry * (1.0 + stop_loss_ratio)
+        stop_loss = round(stop_loss, digits)
 
     take_profit: float | None = None
-    if take_profit_limit_ratio > 0:
+    if take_profit_ratio > 0:
         if normalized_side == "long":
-            take_profit = entry * (1.0 + take_profit_limit_ratio)
+            take_profit = entry * (1.0 + take_profit_ratio)
         else:
-            take_profit = entry * (1.0 - take_profit_limit_ratio)
+            take_profit = entry * (1.0 - take_profit_ratio)
+        take_profit = round(take_profit, digits)
 
     return {
         "entry": entry,
@@ -180,9 +620,209 @@ def determine_order_limits(
     }
 
 
+def place_market_order(
+    client: Mt5TradingClient,
+    *,
+    symbol: str,
+    volume: float,
+    order_side: OrderSide,
+    order_filling_mode: OrderFillingMode = "IOC",
+    order_time_mode: OrderTimeMode = "GTC",
+    sl: float | None = None,
+    tp: float | None = None,
+    position: int | None = None,
+    dry_run: bool = False,
+) -> dict[str, object]:
+    """Place one normalized market order or return a dry-run result.
+
+    ``pdmt5.Mt5TradingClient.order_send()`` raises only when MT5 returns no
+    response. When MT5 returns a response with a known non-success retcode, this
+    helper returns ``status="failed"`` and keeps the normalized response
+    details for callers to inspect.
+
+    Returns:
+        Normalized execution result containing request and response details.
+
+    Raises:
+        Mt5TradingError: If volume or required tick data is invalid.
+    """
+    if volume <= 0:
+        msg = "volume must be positive."
+        raise Mt5TradingError(msg)
+    side = _normalize_order_side(order_side)
+    tick = get_tick_snapshot(client, symbol)
+    price = tick["ask"] if side == "BUY" else tick["bid"]
+    if not isinstance(price, int | float) or price <= 0:
+        msg = f"Tick price is unavailable for {symbol!r}."
+        raise Mt5TradingError(msg)
+    request = {
+        "action": client.mt5.TRADE_ACTION_DEAL,
+        "symbol": symbol,
+        "volume": volume,
+        "type": (
+            client.mt5.ORDER_TYPE_BUY if side == "BUY" else client.mt5.ORDER_TYPE_SELL
+        ),
+        "price": float(price),
+        "type_filling": _resolve_mt5_constant(
+            client.mt5,
+            "ORDER_FILLING",
+            order_filling_mode,
+            _ORDER_FILLING_MODES,
+        ),
+        "type_time": _resolve_mt5_constant(
+            client.mt5,
+            "ORDER_TIME",
+            order_time_mode,
+            _ORDER_TIME_MODES,
+        ),
+    }
+    if sl is not None:
+        request["sl"] = sl
+    if tp is not None:
+        request["tp"] = tp
+    if position is not None:
+        request["position"] = position
+    if dry_run:
+        return {
+            "status": "dry_run",
+            "symbol": symbol,
+            "order_side": side,
+            "volume": volume,
+            "retcode": None,
+            "comment": None,
+            "request": request,
+            "response": None,
+            "dry_run": True,
+        }
+    response = client.order_send(request)
+    response_dict = _snapshot_from_value(response, ())
+    retcode = response_dict.get("retcode")
+    return {
+        "status": _order_status_from_retcode(client.mt5, retcode),
+        "symbol": symbol,
+        "order_side": side,
+        "volume": volume,
+        "retcode": retcode,
+        "comment": response_dict.get("comment"),
+        "request": request,
+        "response": response_dict,
+        "dry_run": False,
+    }
+
+
+def _filter_positions(
+    positions: pd.DataFrame,
+    *,
+    symbols: str | list[str] | None = None,
+    tickets: list[int] | None = None,
+) -> pd.DataFrame:
+    frame = positions
+    if symbols is not None:
+        symbol_set = {symbols} if isinstance(symbols, str) else set(symbols)
+        frame = frame.loc[frame["symbol"].isin(symbol_set)]
+    if tickets is not None:
+        frame = frame.loc[frame["ticket"].isin(tickets)]
+    return frame
+
+
+def close_open_positions(
+    client: Mt5TradingClient,
+    *,
+    symbols: str | list[str] | None = None,
+    tickets: list[int] | None = None,
+    dry_run: bool = False,
+) -> list[dict[str, object]]:
+    """Close matching open positions.
+
+    Returns:
+        Normalized execution results for matching positions.
+    """
+    positions = _filter_positions(
+        get_positions_frame(client),
+        symbols=symbols,
+        tickets=tickets,
+    )
+    results: list[dict[str, object]] = []
+    for row in positions.to_dict("records"):
+        pos_type = row["type"]
+        side: OrderSide = "SELL" if pos_type == client.mt5.POSITION_TYPE_BUY else "BUY"
+        result = place_market_order(
+            client,
+            symbol=str(row["symbol"]),
+            volume=float(row["volume"]),
+            order_side=side,
+            position=int(row["ticket"]),
+            dry_run=dry_run,
+        )
+        results.append(result)
+    return results
+
+
+def update_sltp_for_open_positions(
+    client: Mt5TradingClient,
+    *,
+    symbol: str | None = None,
+    tickets: list[int] | None = None,
+    stop_loss: float | None = None,
+    take_profit: float | None = None,
+    dry_run: bool = False,
+) -> list[dict[str, object]]:
+    """Update SL/TP for matching open positions.
+
+    Returns:
+        Normalized execution results for matching positions.
+    """
+    positions = _filter_positions(
+        get_positions_frame(client),
+        symbols=symbol,
+        tickets=tickets,
+    )
+    results: list[dict[str, object]] = []
+    for row in positions.to_dict("records"):
+        request = {
+            "action": client.mt5.TRADE_ACTION_SLTP,
+            "symbol": row["symbol"],
+            "position": row["ticket"],
+        }
+        sl = _optional_price(row.get("sl") if stop_loss is None else stop_loss)
+        tp = _optional_price(row.get("tp") if take_profit is None else take_profit)
+        if sl is not None:
+            request["sl"] = sl
+        if tp is not None:
+            request["tp"] = tp
+        if dry_run:
+            response = None
+            status = "dry_run"
+        else:
+            response = _snapshot_from_value(client.order_send(request), ())
+            status = "executed"
+        results.append(
+            {
+                "status": status,
+                "symbol": row["symbol"],
+                "order_side": "BUY"
+                if row["type"] == client.mt5.POSITION_TYPE_BUY
+                else "SELL",
+                "volume": row["volume"],
+                "retcode": None if response is None else response.get("retcode"),
+                "comment": None if response is None else response.get("comment"),
+                "request": request,
+                "response": response,
+                "dry_run": dry_run,
+            },
+        )
+    return results
+
+
 @contextmanager
 def mt5_trading_session(
     config: Mt5Config | None = None,
+    *,
+    login: int | str | None = None,
+    password: str | None = None,
+    server: str | None = None,
+    path: str | None = None,
+    timeout: int | None = None,
     retry_count: int = 0,
 ) -> Iterator[Mt5TradingClient]:
     """Open a trading-capable MT5 session and always shut down safely.
@@ -195,16 +835,27 @@ def mt5_trading_session(
     Args:
         config: MT5 connection configuration. Defaults to an empty config that
             attaches to a running terminal.
+        login: Optional trading account login.
+        password: Optional trading account password.
+        server: Optional trading server name.
+        path: Optional terminal executable path.
+        timeout: Optional connection timeout in milliseconds.
         retry_count: Number of initialization retries passed to
             ``Mt5TradingClient``.
 
     Yields:
         Connected ``Mt5TradingClient`` bound to the session.
     """
-    mt5_config = config or build_config()
+    client = create_trading_client(
-    client = Mt5TradingClient(config=mt5_config, retry_count=retry_count)
+        config=config,
+        login=login,
+        password=password,
+        server=server,
+        path=path,
+        timeout=timeout,
+        retry_count=retry_count,
+    )
     try:
-        client.initialize_and_login_mt5()
         yield client
     finally:
         client.shutdown()

mt5cli/utils.py

@@ -241,6 +241,20 @@ def detect_format(
     raise ValueError(msg)
 
 
+def coerce_login(login: int | str | None) -> int | None:
+    """Coerce a login value to int, treating empty strings as unset.
+
+    Returns:
+        Integer login, or None when unset or an empty string.
+    """
+    if login is None or isinstance(login, int):
+        return login
+    text = login.strip()
+    if not text:
+        return None
+    return int(text)
+
+
 def export_dataframe_to_sqlite(
     df: pd.DataFrame,
     output_path: Path,

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "mt5cli"
-version = "0.7.2"
+version = "0.8.0"
 description = "Generic MT5 data and execution infrastructure for Python applications"
 authors = [{name = "dceoy", email = "dceoy@users.noreply.github.com"}]
 maintainers = [{name = "dceoy", email = "dceoy@users.noreply.github.com"}]

tests/test_history.py

@@ -48,6 +48,7 @@ from mt5cli.history import (
     resolve_history_datasets,
     resolve_history_tick_flags,
     resolve_history_timeframes,
+    resolve_rate_table_name,
     resolve_rate_tables,
     resolve_rate_view_name,
     resolve_rate_view_names,
@@ -63,6 +64,15 @@ from mt5cli.utils import TIMEFRAME_MAP, Dataset, IfExists
 class TestResolveRateViewName:
     """Tests for resolve_rate_view_name and resolve_rate_view_names."""
 
+    def test_resolve_rate_table_name_returns_normalized_table(self) -> None:
+        """Test canonical normalized rates table name is stable."""
+        assert resolve_rate_table_name("EURUSD", "M1") == "rates"
+
+    def test_resolve_rate_table_name_rejects_empty_symbol(self) -> None:
+        """Test canonical rate table resolution validates symbols."""
+        with pytest.raises(ValueError, match="symbol must not be empty"):
+            resolve_rate_table_name(" ", "M1")
+
     def test_missing_database_path_does_not_create_file(self, tmp_path: Path) -> None:
         """Test resolving against a missing path does not create a database."""
         db_path = tmp_path / "missing.db"
@@ -416,6 +426,32 @@ class TestLoadRateData:
             frame = load_rate_data_from_connection(conn, "rate_view")
         assert list(frame["close"]) == [1.0]
 
+    def test_load_rate_series_from_sqlite_table_style(
+        self,
+        tmp_path: Path,
+    ) -> None:
+        """Test public table-style loader returns one rate DataFrame."""
+        db_path = tmp_path / "table-style.db"
+        with sqlite3.connect(db_path) as conn:
+            conn.execute("CREATE TABLE rates(time TEXT, close REAL)")
+            conn.executemany(
+                "INSERT INTO rates(time, close) VALUES (?, ?)",
+                [
+                    ("2024-01-01T00:00:00+00:00", 1.0),
+                    ("2024-01-01T00:01:00+00:00", 1.1),
+                ],
+            )
+
+        frame = load_rate_series_from_sqlite(db_path, table="rates", count=1)
+
+        assert isinstance(frame, pd.DataFrame)
+        assert list(frame["close"]) == [1.1]
+
+    def test_load_rate_series_from_sqlite_requires_targets_without_table(self) -> None:
+        """Test multi-series loading requires targets when table is omitted."""
+        with pytest.raises(ValueError, match="targets are required"):
+            load_rate_series_from_sqlite("unused.db", count=1)
+
     def test_loads_quoted_identifier(self, tmp_path: Path) -> None:
         """Test table names are quoted safely."""
         db_path = tmp_path / "quoted.db"

tests/test_sdk.py

@@ -37,6 +37,7 @@ from mt5cli.sdk import (
     copy_rates_range,
     copy_ticks_from,
     copy_ticks_range,
+    fetch_latest_closed_rates,
     history_deals,
     history_orders,
     last_error,
@@ -61,7 +62,7 @@ from mt5cli.sdk import (
     update_history_with_config,
     version,
 )
-from mt5cli.utils import Dataset, IfExists
+from mt5cli.utils import Dataset, IfExists, coerce_login
 
 
 class _TerminalInfo(NamedTuple):
@@ -1301,12 +1302,12 @@ class TestAccountSpec:
         expected: int | None,
     ) -> None:
         """Test login values are normalized for account configs."""
-        assert sdk._coerce_login(login) == expected  # type: ignore[reportPrivateUsage]
+        assert coerce_login(login) == expected
 
     def test_coerce_login_rejects_non_numeric_string(self) -> None:
         """Test non-numeric login strings raise ValueError."""
         with pytest.raises(ValueError, match="invalid literal"):
-            sdk._coerce_login("abc")  # type: ignore[reportPrivateUsage]
+            coerce_login("abc")
 
 
 class TestCollectLatestRatesForAccounts:
@@ -1662,6 +1663,62 @@ class TestCollectLatestClosedRatesForAccounts:
         )
 
 
+class TestFetchLatestClosedRates:
+    """Tests for fetch_latest_closed_rates."""
+
+    def test_fetches_extra_bar_and_drops_forming_row(self) -> None:
+        """Test single-symbol closed-bar helper hides the forming bar."""
+        client = MagicMock()
+        client.latest_rates.return_value = pd.DataFrame(
+            {
+                "time": [1, 2, 3],
+                "close": [1.0, 1.1, 1.2],
+            },
+        )
+
+        result = fetch_latest_closed_rates(
+            client,
+            symbol="EURUSD",
+            granularity="M1",
+            count=2,
+        )
+
+        client.latest_rates.assert_called_once_with(
+            "EURUSD",
+            "M1",
+            3,
+            start_pos=0,
+        )
+        assert list(result["close"]) == [1.0, 1.1]
+
+    def test_raises_when_no_closed_bars_are_available(self) -> None:
+        """Test empty closed-bar results raise an actionable ValueError."""
+        client = MagicMock()
+        client.latest_rates.return_value = pd.DataFrame({"close": [1.0]})
+
+        with pytest.raises(ValueError, match="Rate data is empty"):
+            fetch_latest_closed_rates(
+                client,
+                symbol="EURUSD",
+                granularity="M1",
+                count=1,
+            )
+
+    def test_rejects_non_positive_count_before_fetching(self) -> None:
+        """Test invalid count values fail before calling MT5."""
+        client = MagicMock()
+
+        with pytest.raises(ValueError, match="count must be positive"):
+            fetch_latest_closed_rates(
+                client,
+                symbol="EURUSD",
+                granularity="M1",
+                count=0,
+            )
+
+        client.latest_rates.assert_not_called()
+
+
 class TestCollectLatestClosedRatesByGranularity:
     """Tests for collect_latest_closed_rates_by_granularity."""
 

uv.lock

@@ -487,7 +487,7 @@ wheels = [
 
 [[package]]
 name = "mt5cli"
-version = "0.7.2"
+version = "0.8.0"
 source = { editable = "." }
 dependencies = [
     { name = "click" },