diff --git a/pyproject.toml b/pyproject.toml
index 6481d59..db073e0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "alpha-engine-lib"
-version = "0.40.0"
+version = "0.40.1"
 description = "Shared utilities for the Alpha Engine modules: preflight, logging, ArcticDB, dates, decision capture, cost telemetry, Anthropic payload chokepoint, artifact freshness, RAG, agent schemas, SSM secrets, Telegram + SNS alerts, EC2 spot resilience, SSM log-capture, SSM dispatcher, Step-Functions execution-state projection, and S3-conditional-PUT writer locks. Full surface documented in README."
 readme = "README.md"
 # EC2 still runs Python 3.9 on the always-on micro instance (boto3 drops
diff --git a/src/alpha_engine_lib/__init__.py b/src/alpha_engine_lib/__init__.py
index 32b0506..6a9887f 100644
--- a/src/alpha_engine_lib/__init__.py
+++ b/src/alpha_engine_lib/__init__.py
@@ -1,3 +1,3 @@
 """alpha-engine-lib — shared utilities for Alpha Engine modules."""
 
-__version__ = "0.40.0"
+__version__ = "0.40.1"
diff --git a/src/alpha_engine_lib/cost.py b/src/alpha_engine_lib/cost.py
index 46dc2b7..9e4cc1b 100644
--- a/src/alpha_engine_lib/cost.py
+++ b/src/alpha_engine_lib/cost.py
@@ -58,6 +58,7 @@
 
 from __future__ import annotations
 
+import re
 from datetime import date, datetime, timezone
 from importlib import resources
 from pathlib import Path
@@ -68,6 +69,17 @@
 
 from alpha_engine_lib.decision_capture import ModelMetadata
 
+# Anthropic SDK model IDs come in two forms: the family alias
+# (e.g. ``claude-haiku-4-5``) and the dated snapshot form
+# (e.g. ``claude-haiku-4-5-20251001``). ``Message.model`` returns the dated
+# form even when the caller requested the alias, but our pricing YAML is
+# keyed on the alias so a new snapshot date doesn't require a card refresh.
+_DATED_SNAPSHOT_SUFFIX_RE = re.compile(r"-\d{8}$")
+
+
+def _strip_dated_snapshot_suffix(model_name: str) -> str:
+    return _DATED_SNAPSHOT_SUFFIX_RE.sub("", model_name)
+
 if TYPE_CHECKING:
     # Structural Protocol below describes the only attributes we touch on
     # an Anthropic SDK ``Message`` — kept here so that ``anthropic`` does
@@ -172,14 +184,27 @@ def get(self, model_name: str, at: datetime | date) -> PriceCard:
         component is used for lookup) or a ``date``. The returned card is
         the one whose ``effective_from`` is the latest among cards ≤ ``at``.
 
-        Raises :exc:`PriceCardLookupError` if the model has no cards or
-        every card's ``effective_from`` is later than ``at``.
+        Lookup tries the model name as-given first; on miss, retries with
+        any trailing ``-YYYYMMDD`` snapshot suffix stripped. This lets the
+        YAML stay keyed on family aliases (``claude-haiku-4-5``) while
+        accepting the dated form (``claude-haiku-4-5-20251001``) that the
+        Anthropic SDK returns in ``Message.model``.
+
+        Raises :exc:`PriceCardLookupError` if neither form matches.
         """
         query_date = at.date() if isinstance(at, datetime) else at
-        candidates = [
-            c for c in self.cards
-            if c.model_name == model_name and c.effective_from <= query_date
-        ]
+
+        def _candidates_for(name: str) -> list[PriceCard]:
+            return [
+                c for c in self.cards
+                if c.model_name == name and c.effective_from <= query_date
+            ]
+
+        candidates = _candidates_for(model_name)
+        if not candidates:
+            alias = _strip_dated_snapshot_suffix(model_name)
+            if alias != model_name:
+                candidates = _candidates_for(alias)
         if not candidates:
             raise PriceCardLookupError(
                 f"No price card for model {model_name!r} active on {query_date}"
diff --git a/tests/test_cost.py b/tests/test_cost.py
index 8fd0a81..18c3e29 100644
--- a/tests/test_cost.py
+++ b/tests/test_cost.py
@@ -155,6 +155,47 @@ def test_query_before_first_effective_date_hard_fails(self):
             self.table.get("haiku", date(2025, 12, 31))
 
 
+class TestPriceTableLookupDatedSnapshotSuffix:
+    """Anthropic SDK returns ``Message.model`` in the dated snapshot form
+    (e.g. ``claude-haiku-4-5-20251001``) even when the caller requested
+    the alias; the YAML is keyed on the alias. Lookup must accept both.
+    """
+
+    def setup_method(self):
+        self.table = PriceTable(cards=[
+            _card("claude-haiku-4-5", 2026, 1, 1, in_p=1.0),
+            _card("claude-sonnet-4-6", 2026, 1, 1, in_p=3.0),
+        ])
+
+    def test_dated_suffix_falls_back_to_alias(self):
+        c = self.table.get("claude-haiku-4-5-20251001", date(2026, 5, 28))
+        assert c.input_per_1m == 1.0
+
+    def test_alias_lookup_unchanged(self):
+        c = self.table.get("claude-haiku-4-5", date(2026, 5, 28))
+        assert c.input_per_1m == 1.0
+
+    def test_exact_dated_match_wins_over_alias_fallback(self):
+        # If someone adds a dated card explicitly, it takes precedence.
+        table = PriceTable(cards=[
+            _card("claude-haiku-4-5", 2026, 1, 1, in_p=1.0),
+            _card("claude-haiku-4-5-20251001", 2026, 1, 1, in_p=9.99),
+        ])
+        c = table.get("claude-haiku-4-5-20251001", date(2026, 5, 28))
+        assert c.input_per_1m == 9.99
+
+    def test_unknown_alias_with_dated_suffix_still_hard_fails(self):
+        with pytest.raises(
+            PriceCardLookupError, match="claude-foo-9-9-20251001"
+        ):
+            self.table.get("claude-foo-9-9-20251001", date(2026, 5, 28))
+
+    def test_non_dated_suffix_is_not_stripped(self):
+        # Bare 8-digit substring without leading dash → no normalization.
+        with pytest.raises(PriceCardLookupError):
+            self.table.get("claude-haiku-4-5.20251001", date(2026, 5, 28))
+
+
 # ── compute_cost ──────────────────────────────────────────────────────────