From 42a2b5f057f4ff1be2ec37ab3189ff7631ee89e7 Mon Sep 17 00:00:00 2001 From: Daniel Vainshtein Date: Thu, 13 Aug 2026 14:06:22 +0300 Subject: [PATCH] fix(bedrock): guard cache-detail split against partial/unrecognized ttl entries Address review feedback on #36762: - Only use the parsed 5m/1h split when it fully accounts for cacheWriteInputTokens; an unrecognized ttl or missing entry now falls back to the aggregate (previous behavior) instead of silently understating cost. - Mark TypedDict fields ReadOnly (AWS response data, never constructed by us) to satisfy the repo's type-discipline lint gate. - Trim comments and add Final to locals per repo style. Co-Authored-By: pi (Claude/GPT via @earendil-works/pi-coding-agent) --- .../bedrock/chat/converse_transformation.py | 18 +++++++------- litellm/types/llms/bedrock.py | 24 +++++++++---------- .../chat/test_converse_transformation.py | 21 ++++++++++++++++ 3 files changed, 42 insertions(+), 21 deletions(-) diff --git a/litellm/llms/bedrock/chat/converse_transformation.py b/litellm/llms/bedrock/chat/converse_transformation.py index 9e7c86e615f..dbea1783dc2 100644 --- a/litellm/llms/bedrock/chat/converse_transformation.py +++ b/litellm/llms/bedrock/chat/converse_transformation.py @@ -1773,17 +1773,17 @@ class AmazonConverseConfig(BaseConfig): @staticmethod def _parse_cache_details(usage: ConverseTokenUsageBlock) -> "CacheCreationTokenDetails | None": - """ - Split Converse's aggregate cacheWriteInputTokens into the 5m/1h TTL - breakdown from `cacheDetails`, so cost calc can bill each tier - correctly instead of defaulting the whole write to the 5m rate. - https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_CacheDetail.html - """ - cache_details = usage.get("cacheDetails") + """https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_CacheDetail.html""" + cache_details: Final = usage.get("cacheDetails") if not cache_details: return None - tokens_5m = sum(d["inputTokens"] for d in cache_details if d.get("ttl") == "5m") - tokens_1h = sum(d["inputTokens"] for d in cache_details if d.get("ttl") == "1h") + tokens_5m: Final = sum(d["inputTokens"] for d in cache_details if d.get("ttl") == "5m") + tokens_1h: Final = sum(d["inputTokens"] for d in cache_details if d.get("ttl") == "1h") + # An unrecognized ttl or a partial breakdown would silently understate + # the cache-write cost, so only use the split when it fully accounts + # for the aggregate; otherwise fall back to the aggregate-only (5m) cost. + if tokens_5m + tokens_1h != usage.get("cacheWriteInputTokens", 0): + return None return CacheCreationTokenDetails( ephemeral_5m_input_tokens=tokens_5m, ephemeral_1h_input_tokens=tokens_1h, diff --git a/litellm/types/llms/bedrock.py b/litellm/types/llms/bedrock.py index 4c3ed8d6993..847e4066cf3 100644 --- a/litellm/types/llms/bedrock.py +++ b/litellm/types/llms/bedrock.py @@ -2,7 +2,7 @@ import json from enum import Enum from typing import TYPE_CHECKING, Any, Final, Literal -from typing_extensions import Required, TypedDict, override +from typing_extensions import ReadOnly, Required, TypedDict, override from .openai import ChatCompletionToolCallChunk @@ -217,21 +217,21 @@ class ConverseResponseOutputBlock(TypedDict): class CacheDetailBlock(TypedDict): - """Per-TTL cache-write breakdown. https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_CacheDetail.html""" + """Per-TTL cache-write breakdown, read-only AWS response data. https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_CacheDetail.html""" - inputTokens: int - ttl: Literal["5m", "1h"] + inputTokens: ReadOnly[int] + ttl: ReadOnly[Literal["5m", "1h"]] class ConverseTokenUsageBlock(TypedDict, total=False): - inputTokens: Required[int] - outputTokens: Required[int] - totalTokens: Required[int] - cacheReadInputTokenCount: int - cacheReadInputTokens: int - cacheWriteInputTokenCount: int - cacheWriteInputTokens: int - cacheDetails: list[CacheDetailBlock] + inputTokens: Required[ReadOnly[int]] + outputTokens: Required[ReadOnly[int]] + totalTokens: Required[ReadOnly[int]] + cacheReadInputTokenCount: ReadOnly[int] + cacheReadInputTokens: ReadOnly[int] + cacheWriteInputTokenCount: ReadOnly[int] + cacheWriteInputTokens: ReadOnly[int] + cacheDetails: ReadOnly[list[CacheDetailBlock]] # mutable-ok: AWS response array, never mutated after parsing class ServiceTierBlock(TypedDict): diff --git a/tests/test_litellm/llms/bedrock/chat/test_converse_transformation.py b/tests/test_litellm/llms/bedrock/chat/test_converse_transformation.py index 393499fb041..a7d6695ca35 100644 --- a/tests/test_litellm/llms/bedrock/chat/test_converse_transformation.py +++ b/tests/test_litellm/llms/bedrock/chat/test_converse_transformation.py @@ -75,6 +75,27 @@ def test_transform_usage_with_cache_details(): assert details.ephemeral_5m_input_tokens == 288 +def test_transform_usage_with_mismatched_cache_details_falls_back(): + """An unrecognized ttl or partial breakdown must not silently understate + cache-write cost, so the split is only used when it fully accounts for + cacheWriteInputTokens.""" + usage = ConverseTokenUsageBlock( + **{ + "inputTokens": 76, + "outputTokens": 259, + "totalTokens": 335, + "cacheWriteInputTokens": 362, + "cacheDetails": [{"inputTokens": 74, "ttl": "1h"}], # missing the 5m entry + } + ) + config = AmazonConverseConfig() + openai_usage = config._transform_usage(usage) + assert ( + getattr(openai_usage.prompt_tokens_details, "cache_creation_token_details", None) + is None + ) + + def test_transform_usage_without_cache_details_stays_none(): """No cacheDetails in the response (older models/regions) should leave cache_creation_token_details unset, same as before this field existed."""