diff --git a/__init__.py b/__init__.py
index 42a2648..614a8ba 100644
--- a/__init__.py
+++ b/__init__.py
@@ -30,17 +30,6 @@ def libra_stop():
         except Exception as ex:
             logger.warning(ex)
 
-    # Close the Fava client's shared HTTP connection pool. libra_stop is
-    # synchronous, so schedule the close; if the loop is already gone the
-    # sockets die with the process anyway.
-    from .fava_client import _fava_client
-
-    if _fava_client is not None:
-        try:
-            asyncio.get_event_loop().create_task(_fava_client.aclose())
-        except Exception as ex:
-            logger.warning(f"Could not close Fava HTTP client: {ex}")
-
 
 def libra_start():
     """Initialize Libra extension background tasks"""
diff --git a/account_sync.py b/account_sync.py
index 870d1d7..3d82381 100644
--- a/account_sync.py
+++ b/account_sync.py
@@ -285,11 +285,7 @@ async def sync_accounts_from_beancount(force_full_sync: bool = False) -> dict:
     return stats
 
 
-async def sync_single_account_from_beancount(
-    account_name: str,
-    description: Optional[str] = None,
-    assume_exists: bool = False,
-) -> bool:
+async def sync_single_account_from_beancount(account_name: str) -> bool:
     """
     Sync a single account from Beancount to Libra DB.
 
@@ -298,13 +294,6 @@ async def sync_single_account_from_beancount(
 
     Args:
         account_name: Hierarchical account name (e.g., "Expenses:Food")
-        description: Description for the Libra DB row (only used with
-            assume_exists — otherwise read from Beancount metadata)
-        assume_exists: Skip the Fava existence lookup. Pass when the
-            caller just wrote the Open directive itself — verifying via
-            a second serialized get_all_accounts round-trip doubles the
-            latency of every account create for no information gain
-            (libra-#53).
 
     Returns:
         True if account was created/updated, False if it already existed or failed
@@ -317,22 +306,6 @@ async def sync_single_account_from_beancount(
         logger.debug(f"Account already exists: {account_name}")
         return False
 
-    if assume_exists:
-        try:
-            await create_account(
-                CreateAccount(
-                    name=account_name,
-                    account_type=infer_account_type_from_name(account_name),
-                    description=description,
-                    user_id=extract_user_id_from_account_name(account_name),
-                )
-            )
-            logger.info(f"Created account (writer-asserted): {account_name}")
-            return True
-        except Exception as e:
-            logger.error(f"Failed to sync account {account_name}: {e}")
-            return False
-
     # Get from Beancount
     fava = get_fava_client()
     try:
diff --git a/beancount_format.py b/beancount_format.py
index fbdfba9..4cbc5c7 100644
--- a/beancount_format.py
+++ b/beancount_format.py
@@ -115,18 +115,13 @@ def format_balance(
     account: str,
     amount: int,
     currency: str = "SATS"
-) -> Dict[str, Any]:
+) -> str:
     """
-    Format a balance assertion directive for Fava's JSON API.
+    Format a balance assertion directive for Beancount.
 
     Balance assertions verify that an account has an expected balance on a specific date.
     They are checked automatically by Beancount when the file is loaded.
 
-    Fava's `deserialise` (fava/serialisation.py) expects
-    `{"t": "Balance", "amount": {"number", "currency"}, ...}` — the
-    previous source-string return 500'd on every assertion create
-    (libra-#39).
-
     Args:
         date_val: Date of the balance assertion
         account: Account name (e.g., "Assets:Bitcoin:Lightning")
@@ -134,15 +129,15 @@ def format_balance(
         currency: Currency code (default: "SATS")
 
     Returns:
-        Fava API Balance entry dict ready for `fava.add_entry`.
+        Beancount balance directive as a string
+
+    Example:
+        >>> format_balance(date(2025, 11, 10), "Assets:Bitcoin:Lightning", 1500000, "SATS")
+        '2025-11-10 balance Assets:Bitcoin:Lightning  1500000 SATS'
     """
-    return {
-        "t": "Balance",
-        "date": date_val.strftime('%Y-%m-%d'),
-        "account": account,
-        "amount": {"number": str(amount), "currency": currency},
-        "meta": {},
-    }
+    date_str = date_val.strftime('%Y-%m-%d')
+    # Two spaces between account and amount (Beancount convention)
+    return f"{date_str} balance {account}  {amount} {currency}"
 
 
 def format_posting_with_cost(
diff --git a/fava_client.py b/fava_client.py
index faad8f7..a7d1703 100644
--- a/fava_client.py
+++ b/fava_client.py
@@ -20,8 +20,7 @@ See: https://github.com/beancount/fava/blob/main/src/fava/json_api.py
 import asyncio
 import re
 import httpx
-from contextlib import asynccontextmanager
-from typing import Any, AsyncIterator, Callable, Dict, List, Optional
+from typing import Any, Dict, List, Optional
 from decimal import Decimal
 from datetime import date, datetime
 from loguru import logger
@@ -45,34 +44,6 @@ def _infer_target_file(account_name: str) -> str:
     return "accounts/chart.beancount"
 
 
-# Posting amount-string patterns shared by the balance parsers. Fava's
-# @@ → @ normalisation can emit decimal SATS values, so every SATS group
-# must tolerate decimals (the old integer-only pattern silently dropped
-# those postings from balances).
-_TOTAL_PRICE_RE = re.compile(r'^(-?[\d.]+)\s+([A-Z]{3})\s+@@\s+(-?[\d.]+)\s+SATS$')
-_UNIT_PRICE_RE = re.compile(r'^(-?[\d.]+)\s+([A-Z]{3})\s+@\s+([\d.]+)\s+SATS$')
-_FIAT_AMOUNT_RE = re.compile(r'^(-?[\d.]+)\s+([A-Z]{3})$')
-_SATS_AMOUNT_RE = re.compile(r'^(-?[\d.]+)\s+SATS')
-
-
-def _sats_to_int(value: str) -> int:
-    """Parse a (possibly decimal) SATS amount string to whole sats."""
-    return int(Decimal(value))
-
-
-# Account names/patterns are interpolated into BQL string literals; restrict
-# them to Beancount account characters so caller-supplied input can't break
-# out of the quoted literal.
-_BQL_ACCOUNT_RE = re.compile(r'^[A-Za-z0-9:_-]+$')
-
-
-def _validate_bql_account(value: str) -> str:
-    """Validate a value bound for interpolation into a BQL string literal."""
-    if not _BQL_ACCOUNT_RE.match(value):
-        raise ValueError(f"Invalid account name for BQL query: {value!r}")
-    return value
-
-
 def _escape_beancount_string(value: str) -> str:
     """Escape a value for safe inclusion in a Beancount string literal.
 
@@ -165,27 +136,6 @@ class FavaClient:
         self._main_dir_cache: Optional[str] = None
         self._main_dir_lock = asyncio.Lock()
 
-        # Shared HTTP client, created lazily on first use. One client
-        # means one connection pool instead of a TCP handshake per call.
-        self._http: Optional[httpx.AsyncClient] = None
-
-    @asynccontextmanager
-    async def _client(self) -> AsyncIterator[httpx.AsyncClient]:
-        """Yield the shared HTTP client (lazily created).
-
-        Kept as a context manager so call sites read the same as the
-        per-call clients they replace; the client itself is NOT closed on
-        exit — call `aclose()` at extension shutdown.
-        """
-        if self._http is None or self._http.is_closed:
-            self._http = httpx.AsyncClient(timeout=self.timeout)
-        yield self._http
-
-    async def aclose(self) -> None:
-        """Close the shared HTTP client (extension shutdown)."""
-        if self._http is not None and not self._http.is_closed:
-            await self._http.aclose()
-
     async def _resolve_target_file(self, target_file: str) -> str:
         """
         Turn a relative include path into the absolute path fava expects.
@@ -210,7 +160,7 @@ class FavaClient:
         if self._main_dir_cache is None:
             async with self._main_dir_lock:
                 if self._main_dir_cache is None:
-                    async with self._client() as client:
+                    async with httpx.AsyncClient(timeout=self.timeout) as client:
                         resp = await client.get(f"{self.base_url}/options")
                         resp.raise_for_status()
                         main_file = resp.json()["data"]["beancount_options"]["filename"]
@@ -286,7 +236,7 @@ class FavaClient:
         # Acquire global write lock to serialize ledger modifications
         async with self._write_lock:
             try:
-                async with self._client() as client:
+                async with httpx.AsyncClient(timeout=self.timeout) as client:
                     response = await client.put(
                         f"{self.base_url}/add_entries",
                         json={"entries": [entry]},
@@ -400,11 +350,10 @@ class FavaClient:
 
         # Use sum(weight) for SATS and sum(number) for fiat
         # Note: BQL doesn't support != operator, so use flag = '*' to exclude pending
-        _validate_bql_account(account_name)
         query = f"SELECT sum(number), sum(weight) WHERE account = '{account_name}' AND flag = '*'"
 
         try:
-            async with self._client() as client:
+            async with httpx.AsyncClient(timeout=self.timeout) as client:
                 response = await client.get(
                     f"{self.base_url}/query",
                     params={"query_string": query}
@@ -497,14 +446,14 @@ class FavaClient:
                 import re
 
                 # Try total price notation: "50.00 EUR @@ 50000 SATS"
-                total_price_match = _TOTAL_PRICE_RE.match(amount_str)
+                total_price_match = re.match(r'^(-?[\d.]+)\s+([A-Z]{3})\s+@@\s+(-?\d+)\s+SATS$', amount_str)
                 # Try per-unit price notation: "50.00 EUR @ 1000.5 SATS"
-                unit_price_match = _UNIT_PRICE_RE.match(amount_str)
+                unit_price_match = re.match(r'^(-?[\d.]+)\s+([A-Z]{3})\s+@\s+([\d.]+)\s+SATS$', amount_str)
 
                 if total_price_match:
                     fiat_amount = Decimal(total_price_match.group(1))
                     fiat_currency = total_price_match.group(2)
-                    sats_amount = _sats_to_int(total_price_match.group(3))
+                    sats_amount = int(total_price_match.group(3))
 
                     if fiat_currency not in fiat_balances:
                         fiat_balances[fiat_currency] = Decimal(0)
@@ -531,8 +480,8 @@ class FavaClient:
                     accounts_dict[account_name]["sats"] += sats_amount
 
                 # Try simple fiat format: "50.00 EUR" (check metadata for sats)
-                elif _FIAT_AMOUNT_RE.match(amount_str):
-                    fiat_match = _FIAT_AMOUNT_RE.match(amount_str)
+                elif re.match(r'^(-?[\d.]+)\s+([A-Z]{3})$', amount_str):
+                    fiat_match = re.match(r'^(-?[\d.]+)\s+([A-Z]{3})$', amount_str)
                     if fiat_match and fiat_match.group(2) in ('EUR', 'USD', 'GBP'):
                         fiat_amount = Decimal(fiat_match.group(1))
                         fiat_currency = fiat_match.group(2)
@@ -553,9 +502,9 @@ class FavaClient:
 
                 else:
                     # Old format: SATS with cost/price notation - extract SATS amount
-                    sats_match = _SATS_AMOUNT_RE.match(amount_str)
+                    sats_match = re.match(r'^(-?\d+)\s+SATS', amount_str)
                     if sats_match:
-                        sats_amount = _sats_to_int(sats_match.group(1))
+                        sats_amount = int(sats_match.group(1))
                         total_sats += sats_amount
 
                         # Track per account
@@ -654,14 +603,14 @@ class FavaClient:
                 import re
 
                 # Try total price notation: "50.00 EUR @@ 50000 SATS"
-                total_price_match = _TOTAL_PRICE_RE.match(amount_str)
+                total_price_match = re.match(r'^(-?[\d.]+)\s+([A-Z]{3})\s+@@\s+(-?\d+)\s+SATS$', amount_str)
                 # Try per-unit price notation: "50.00 EUR @ 1000.5 SATS"
-                unit_price_match = _UNIT_PRICE_RE.match(amount_str)
+                unit_price_match = re.match(r'^(-?[\d.]+)\s+([A-Z]{3})\s+@\s+([\d.]+)\s+SATS$', amount_str)
 
                 if total_price_match:
                     fiat_amount = Decimal(total_price_match.group(1))
                     fiat_currency = total_price_match.group(2)
-                    sats_amount = _sats_to_int(total_price_match.group(3))
+                    sats_amount = int(total_price_match.group(3))
 
                     if fiat_currency not in user_data[user_id]["fiat_balances"]:
                         user_data[user_id]["fiat_balances"][fiat_currency] = Decimal(0)
@@ -680,8 +629,8 @@ class FavaClient:
                     user_data[user_id]["balance"] += sats_amount
 
                 # Try simple fiat format: "50.00 EUR" (check metadata for sats)
-                elif _FIAT_AMOUNT_RE.match(amount_str):
-                    fiat_match = _FIAT_AMOUNT_RE.match(amount_str)
+                elif re.match(r'^(-?[\d.]+)\s+([A-Z]{3})$', amount_str):
+                    fiat_match = re.match(r'^(-?[\d.]+)\s+([A-Z]{3})$', amount_str)
                     if fiat_match and fiat_match.group(2) in ('EUR', 'USD', 'GBP'):
                         fiat_amount = Decimal(fiat_match.group(1))
                         fiat_currency = fiat_match.group(2)
@@ -699,9 +648,9 @@ class FavaClient:
 
                 else:
                     # Old format: SATS with cost/price notation
-                    sats_match = _SATS_AMOUNT_RE.match(amount_str)
+                    sats_match = re.match(r'^(-?\d+)\s+SATS', amount_str)
                     if sats_match:
-                        sats_amount = _sats_to_int(sats_match.group(1))
+                        sats_amount = int(sats_match.group(1))
                         user_data[user_id]["balance"] += sats_amount
 
                     # Extract fiat from cost syntax or metadata (backward compatibility)
@@ -734,12 +683,9 @@ class FavaClient:
             True if Fava responds, False otherwise
         """
         try:
-            async with self._client() as client:
-                # Health probes stay fast regardless of the configured
-                # request timeout.
+            async with httpx.AsyncClient(timeout=2.0) as client:
                 response = await client.get(
-                    f"{self.base_url}/changed",
-                    timeout=2.0
+                    f"{self.base_url}/changed"
                 )
                 return response.status_code == 200
         except Exception as e:
@@ -775,13 +721,12 @@ class FavaClient:
         """
         # Build Beancount query
         if account_pattern:
-            _validate_bql_account(account_pattern)
             query = f"SELECT * WHERE account ~ '{account_pattern}' ORDER BY date DESC LIMIT {limit}"
         else:
             query = f"SELECT * ORDER BY date DESC LIMIT {limit}"
 
         try:
-            async with self._client() as client:
+            async with httpx.AsyncClient(timeout=self.timeout) as client:
                 response = await client.get(
                     f"{self.base_url}/query",
                     params={"query_string": query}
@@ -862,7 +807,7 @@ class FavaClient:
             https://beancount.github.io/docs/beancount_query_language.html
         """
         try:
-            async with self._client() as client:
+            async with httpx.AsyncClient(timeout=self.timeout) as client:
                 response = await client.get(
                     f"{self.base_url}/query",
                     params={"query_string": query_string}
@@ -1396,7 +1341,7 @@ class FavaClient:
             # (BQL's SELECT DISTINCT account only returns accounts with postings)
             account_names: set[str] = set()
 
-            async with self._client() as client:
+            async with httpx.AsyncClient(timeout=self.timeout) as client:
                 for endpoint in ("balance_sheet", "income_statement"):
                     try:
                         response = await client.get(f"{self.base_url}/{endpoint}")
@@ -1495,7 +1440,7 @@ class FavaClient:
                 params["time"] = f"{cutoff_date.isoformat()} - {today.isoformat()}"
                 logger.info(f"Querying journal for last {days} days (from {cutoff_date})")
 
-            async with self._client() as client:
+            async with httpx.AsyncClient(timeout=self.timeout) as client:
                 response = await client.get(f"{self.base_url}/journal", params=params)
                 response.raise_for_status()
                 result = response.json()
@@ -1537,7 +1482,7 @@ class FavaClient:
             sha256sum = context["sha256sum"]
         """
         try:
-            async with self._client() as client:
+            async with httpx.AsyncClient(timeout=self.timeout) as client:
                 response = await client.get(
                     f"{self.base_url}/context",
                     params={"entry_hash": entry_hash}
@@ -1584,7 +1529,7 @@ class FavaClient:
         # Acquire global write lock to serialize ledger modifications
         async with self._write_lock:
             try:
-                async with self._client() as client:
+                async with httpx.AsyncClient(timeout=self.timeout) as client:
                     response = await client.put(
                         f"{self.base_url}/source_slice",
                         json={
@@ -1599,78 +1544,11 @@ class FavaClient:
 
             except httpx.HTTPStatusError as e:
                 logger.error(f"Fava update error: {e.response.status_code} - {e.response.text}")
-                if e.response.status_code in (409, 412):
-                    raise ChecksumConflictError(
-                        f"Entry {entry_hash} changed concurrently"
-                    ) from e
                 raise
             except httpx.RequestError as e:
                 logger.error(f"Fava connection error: {e}")
                 raise
 
-    async def transform_source_line(
-        self,
-        filename: str,
-        lineno: int,
-        transform: Callable[[str], str],
-    ) -> bool:
-        """Atomically read-modify-write one line of a ledger source file.
-
-        Holds the global write lock across the whole read-modify-write, so
-        another writer can't slip in between the checksum read and the
-        write (libra-#23: the approve/reject endpoints used to do this
-        read-then-write with raw httpx and no lock).
-
-        The transform receives the current line and returns the new one;
-        returning it unchanged skips the write.
-
-        Returns:
-            True when the line was changed and written, False on a no-op.
-
-        Raises:
-            ValueError: lineno is outside the file.
-            ChecksumConflictError: an out-of-process writer changed the
-                file between read and write (409/412 from Fava).
-        """
-        async with self._write_lock:
-            async with self._client() as client:
-                response = await client.get(
-                    f"{self.base_url}/source",
-                    params={"filename": filename},
-                )
-                response.raise_for_status()
-                source_data = response.json()["data"]
-                sha256sum = source_data["sha256sum"]
-                lines = source_data["source"].split("\n")
-
-                idx = lineno - 1
-                if idx < 0 or idx >= len(lines):
-                    raise ValueError(f"Line {lineno} not found in {filename}")
-
-                new_line = transform(lines[idx])
-                if new_line == lines[idx]:
-                    return False
-                lines[idx] = new_line
-
-                try:
-                    update = await client.put(
-                        f"{self.base_url}/source",
-                        json={
-                            "file_path": filename,
-                            "source": "\n".join(lines),
-                            "sha256sum": sha256sum,
-                        },
-                        headers={"Content-Type": "application/json"},
-                    )
-                    update.raise_for_status()
-                except httpx.HTTPStatusError as e:
-                    if e.response.status_code in (409, 412):
-                        raise ChecksumConflictError(
-                            f"{filename} changed concurrently"
-                        ) from e
-                    raise
-                return True
-
     async def delete_entry(self, entry_hash: str, sha256sum: str) -> str:
         """
         Delete an entry from the Beancount file.
@@ -1693,7 +1571,7 @@ class FavaClient:
         # Acquire global write lock to serialize ledger modifications
         async with self._write_lock:
             try:
-                async with self._client() as client:
+                async with httpx.AsyncClient(timeout=self.timeout) as client:
                     response = await client.delete(
                         f"{self.base_url}/source_slice",
                         params={
@@ -1707,10 +1585,6 @@ class FavaClient:
 
             except httpx.HTTPStatusError as e:
                 logger.error(f"Fava delete error: {e.response.status_code} - {e.response.text}")
-                if e.response.status_code in (409, 412):
-                    raise ChecksumConflictError(
-                        f"Entry {entry_hash} changed concurrently"
-                    ) from e
                 raise
             except httpx.RequestError as e:
                 logger.error(f"Fava connection error: {e}")
@@ -1790,7 +1664,7 @@ class FavaClient:
             # Acquire global write lock to serialize ledger modifications
             async with self._write_lock:
                 try:
-                    async with self._client() as client:
+                    async with httpx.AsyncClient(timeout=self.timeout) as client:
                         # Step 1: Get current source file (fresh read on each attempt)
                         response = await client.get(
                             f"{self.base_url}/source",
diff --git a/tests/test_reconciliation_api.py b/tests/test_reconciliation_api.py
index a168ff8..66757be 100644
--- a/tests/test_reconciliation_api.py
+++ b/tests/test_reconciliation_api.py
@@ -18,6 +18,19 @@ from uuid import uuid4
 import pytest
 
 
+# Tests that try to actually create + check an assertion all hit issue #39:
+# `format_balance` returns a Beancount source string but `fava.add_entry`
+# expects a dict, so Fava 500s on every assertion-create call. The contract
+# violation is on libra's side; mark these strict-xfail so they go green
+# automatically once #39 lands and the format_balance return shape is fixed.
+ASSERTION_CREATE_BROKEN = pytest.mark.xfail(
+    reason="libra/issues/39 — POST /assertions submits a Beancount source string "
+    "to Fava's JSON API and 500s. Drop this marker when the format_balance "
+    "return type is changed to a dict.",
+    strict=True,
+)
+
+
 # ---------------------------------------------------------------------------
 # helpers (local — assertion endpoints don't have wrapper helpers yet)
 # ---------------------------------------------------------------------------
@@ -45,6 +58,7 @@ async def _create_assertion(
 # ---------------------------------------------------------------------------
 
 
+@ASSERTION_CREATE_BROKEN
 @pytest.mark.anyio
 async def test_assertion_against_empty_account_passes(
     client, super_user_headers, standard_accounts,
@@ -65,6 +79,7 @@ async def test_assertion_against_empty_account_passes(
     assert body.get("difference_sats", 0) == 0
 
 
+@ASSERTION_CREATE_BROKEN
 @pytest.mark.anyio
 async def test_assertion_with_wrong_balance_returns_409(
     client, super_user_headers, standard_accounts,
@@ -87,6 +102,7 @@ async def test_assertion_with_wrong_balance_returns_409(
     assert detail.get("difference_sats") == 999_999 or detail.get("difference_sats") == -999_999
 
 
+@ASSERTION_CREATE_BROKEN
 @pytest.mark.anyio
 async def test_assertion_with_tolerance_accepts_small_diff(
     client, super_user_headers, standard_accounts,
@@ -103,6 +119,7 @@ async def test_assertion_with_tolerance_accepts_small_diff(
     assert r.json().get("status") == "passed"
 
 
+@ASSERTION_CREATE_BROKEN
 @pytest.mark.anyio
 async def test_list_assertions_returns_created(
     client, super_user_headers, standard_accounts,
@@ -128,6 +145,7 @@ async def test_list_assertions_returns_created(
     assert assertion_id in ids, f"created assertion {assertion_id} missing from list {ids}"
 
 
+@ASSERTION_CREATE_BROKEN
 @pytest.mark.anyio
 async def test_get_assertion_by_id(
     client, super_user_headers, standard_accounts,
@@ -149,6 +167,7 @@ async def test_get_assertion_by_id(
     assert r.json().get("id") == assertion_id
 
 
+@ASSERTION_CREATE_BROKEN
 @pytest.mark.anyio
 async def test_recheck_assertion_via_check_endpoint(
     client, super_user_headers, standard_accounts,
@@ -171,6 +190,7 @@ async def test_recheck_assertion_via_check_endpoint(
     assert r.json().get("status") == "passed"
 
 
+@ASSERTION_CREATE_BROKEN
 @pytest.mark.anyio
 async def test_delete_assertion_removes_it(
     client, super_user_headers, standard_accounts,
diff --git a/tests/test_void_reject_api.py b/tests/test_void_reject_api.py
index 0f2b817..66e2180 100644
--- a/tests/test_void_reject_api.py
+++ b/tests/test_void_reject_api.py
@@ -210,69 +210,3 @@ async def test_double_reject_returns_404_on_second_call(
     assert r.status_code in (200, 404), (
         f"second reject should be deterministic, got {r.status_code}: {r.text}"
     )
-
-
-@pytest.mark.anyio
-async def test_concurrent_approve_and_reject_are_serialized(
-    client, super_user_headers, configured_user, standard_accounts,
-):
-    """Two mutations of the same ledger source file fired concurrently must
-    BOTH land. Before libra-#23 each endpoint did its own read-modify-write
-    with raw httpx and no lock, so one writer overwrote the other's change
-    (or 412'd on the stale checksum). Now both route through
-    FavaClient.transform_source_line under the global write lock.
-    """
-    import asyncio
-
-    _, wallet = configured_user
-    approve_tag = f"conc-approve-{uuid4().hex[:6]}"
-    reject_tag = f"conc-reject-{uuid4().hex[:6]}"
-
-    posted = {}
-    for tag in (approve_tag, reject_tag):
-        posted[tag] = await post_expense(
-            client,
-            wallet_inkey=wallet.inkey,
-            user_wallet_id=wallet.id,
-            amount="10.00",
-            currency="EUR",
-            description=tag,
-            expense_account=standard_accounts["expense_food"]["name"],
-        )
-
-    # Force a Fava reload so the approve/reject lookups see both fresh
-    # pending entries (see #37).
-    await list_user_entries(client, wallet_inkey=wallet.inkey)
-
-    r_approve, r_reject = await asyncio.gather(
-        client.post(
-            f"/libra/api/v1/entries/{posted[approve_tag]['id']}/approve",
-            headers=super_user_headers,
-        ),
-        client.post(
-            f"/libra/api/v1/entries/{posted[reject_tag]['id']}/reject",
-            headers=super_user_headers,
-        ),
-    )
-    assert r_approve.status_code == 200, f"approve: {r_approve.text}"
-    assert r_reject.status_code == 200, f"reject: {r_reject.text}"
-
-    # Both mutations must be visible: one entry voided, the other cleared
-    # (a cleared entry no longer matches the pending-only reject lookup).
-    listing = await list_user_entries(client, wallet_inkey=wallet.inkey)
-    entries = listing.get("entries", [])
-    rejected = next(
-        (e for e in entries if reject_tag in (e.get("description") or "")), None,
-    )
-    assert rejected is not None and "voided" in rejected.get("tags", []), (
-        f"rejected entry lost its #voided tag: {rejected}"
-    )
-
-    second_reject = await client.post(
-        f"/libra/api/v1/entries/{posted[approve_tag]['id']}/reject",
-        headers=super_user_headers,
-    )
-    assert second_reject.status_code == 404, (
-        "approved entry should no longer match the pending-only reject "
-        f"lookup, got {second_reject.status_code}"
-    )
diff --git a/views_api.py b/views_api.py
index 1c3269f..2188d7a 100644
--- a/views_api.py
+++ b/views_api.py
@@ -2903,7 +2903,8 @@ async def api_approve_expense_entry(
 
     This updates the transaction in the Beancount file via Fava API.
     """
-    from .fava_client import ChecksumConflictError, get_fava_client
+    import httpx
+    from .fava_client import get_fava_client
 
     fava = get_fava_client()
 
@@ -2938,29 +2939,57 @@ async def api_approve_expense_entry(
             detail="Entry metadata missing filename or lineno"
         )
 
-    # 3. Flip the flag under FavaClient's write lock — the whole
-    # read-modify-write is atomic against every other ledger writer.
-    old_pattern = f"{date_str} !"
+    # 3. Get the source file from Fava
+    async with httpx.AsyncClient(timeout=fava.timeout) as client:
+        response = await client.get(
+            f"{fava.base_url}/source",
+            params={"filename": filename}
+        )
+        response.raise_for_status()
+        source_data = response.json()["data"]
 
-    def _approve(line: str) -> str:
-        if old_pattern not in line:
+        sha256sum = source_data["sha256sum"]
+        source = source_data["source"]
+        lines = source.split('\n')
+
+        # 4. Find and modify the entry at the specified line
+        # Line numbers are 1-indexed, list is 0-indexed
+        entry_line_idx = lineno - 1
+
+        if entry_line_idx >= len(lines):
             raise HTTPException(
                 status_code=HTTPStatus.INTERNAL_SERVER_ERROR,
-                detail=f"Line {lineno} does not contain expected pattern '{old_pattern}'. Found: {line}"
+                detail=f"Line {lineno} not found in source file"
             )
-        return line.replace(old_pattern, f"{date_str} *", 1)
 
-    try:
-        await fava.transform_source_line(filename, lineno, _approve)
-    except ValueError as e:
-        raise HTTPException(
-            status_code=HTTPStatus.INTERNAL_SERVER_ERROR, detail=str(e)
-        )
-    except ChecksumConflictError:
-        raise HTTPException(
-            status_code=HTTPStatus.CONFLICT,
-            detail="Ledger changed concurrently; retry the approval",
+        entry_line = lines[entry_line_idx]
+
+        # Check if the line contains the pending flag pattern
+        old_pattern = f"{date_str} !"
+        if old_pattern not in entry_line:
+            raise HTTPException(
+                status_code=HTTPStatus.INTERNAL_SERVER_ERROR,
+                detail=f"Line {lineno} does not contain expected pattern '{old_pattern}'. Found: {entry_line}"
+            )
+
+        # Replace the flag
+        new_pattern = f"{date_str} *"
+        new_line = entry_line.replace(old_pattern, new_pattern, 1)
+        lines[entry_line_idx] = new_line
+
+        # 5. Write back the modified source
+        new_source = '\n'.join(lines)
+
+        update_response = await client.put(
+            f"{fava.base_url}/source",
+            json={
+                "file_path": filename,
+                "source": new_source,
+                "sha256sum": sha256sum
+            },
+            headers={"Content-Type": "application/json"}
         )
+        update_response.raise_for_status()
 
     logger.info(f"Entry {entry_id} approved (flag changed to *)")
 
@@ -2983,7 +3012,8 @@ async def api_reject_expense_entry(
     Adds #voided tag for audit trail while keeping the '!' flag.
     Voided transactions are excluded from balances but preserved in the ledger.
     """
-    from .fava_client import ChecksumConflictError, get_fava_client
+    import httpx
+    from .fava_client import get_fava_client
 
     fava = get_fava_client()
 
@@ -3018,26 +3048,50 @@ async def api_reject_expense_entry(
             detail="Entry metadata missing filename or lineno"
         )
 
-    # 3. Add the #voided tag under FavaClient's write lock — the whole
-    # read-modify-write is atomic against every other ledger writer.
-    def _void(line: str) -> str:
-        if "#voided" in line:
-            return line  # already voided — no-op
-        return line.rstrip() + ' #voided'
+    # 3. Get the source file from Fava
+    async with httpx.AsyncClient(timeout=fava.timeout) as client:
+        response = await client.get(
+            f"{fava.base_url}/source",
+            params={"filename": filename}
+        )
+        response.raise_for_status()
+        source_data = response.json()["data"]
 
-    try:
-        changed = await fava.transform_source_line(filename, lineno, _void)
-    except ValueError as e:
-        raise HTTPException(
-            status_code=HTTPStatus.INTERNAL_SERVER_ERROR, detail=str(e)
-        )
-    except ChecksumConflictError:
-        raise HTTPException(
-            status_code=HTTPStatus.CONFLICT,
-            detail="Ledger changed concurrently; retry the rejection",
-        )
-    if changed:
-        logger.info(f"Entry {entry_id} rejected (added #voided tag)")
+        sha256sum = source_data["sha256sum"]
+        source = source_data["source"]
+        lines = source.split('\n')
+
+        # 4. Find and modify the entry at the specified line - add #voided tag
+        entry_line_idx = lineno - 1
+
+        if entry_line_idx >= len(lines):
+            raise HTTPException(
+                status_code=HTTPStatus.INTERNAL_SERVER_ERROR,
+                detail=f"Line {lineno} not found in source file"
+            )
+
+        entry_line = lines[entry_line_idx]
+
+        # Add #voided tag if not already present
+        if "#voided" not in entry_line:
+            # Add #voided tag to the transaction line
+            new_line = entry_line.rstrip() + ' #voided'
+            lines[entry_line_idx] = new_line
+
+            # 5. Write back the modified source
+            new_source = '\n'.join(lines)
+
+            update_response = await client.put(
+                f"{fava.base_url}/source",
+                json={
+                    "file_path": filename,
+                    "source": new_source,
+                    "sha256sum": sha256sum
+                },
+                headers={"Content-Type": "application/json"}
+            )
+            update_response.raise_for_status()
+            logger.info(f"Entry {entry_id} rejected (added #voided tag)")
 
     return {
         "message": f"Entry {entry_id} rejected (marked as voided)",
@@ -3766,14 +3820,8 @@ async def api_admin_add_chart_account(
             "already_existed": True,
         }
 
-    # Mirror into libra DB so permissions / metadata layer sees it. We just
-    # wrote the Open directive ourselves, so skip the verification
-    # round-trip through Fava (libra-#53).
-    synced = await sync_single_account_from_beancount(
-        payload.name,
-        description=payload.description,
-        assume_exists=True,
-    )
+    # Mirror into libra DB so permissions / metadata layer sees it.
+    synced = await sync_single_account_from_beancount(payload.name)
 
     return {
         "success": True,