Every OpenAI Responses body carries `error: null` at the top level, and the
completeness check tested the key's presence rather than its value, so it
rejected every single one. The cost was silent: nothing failed, the endpoint
simply never cached, which is exactly the outcome the endpoint was added for.
Found by driving the edge against the real providers rather than the synthetic
fixtures, which carried no error key at all. Reading the value instead of the
key is also more accurate for chat completions and messages, where a real error
body carries a populated error object.
Chat completions and messages were the only cacheable paths. The suite also
drives /v1/embeddings and /v1/responses through the same OpenAI mount, so both
now cache, each with its own completeness rule: a chat response's `choices`
check would reject a perfectly good embedding, and a Responses run that never
reached `response.completed` must stay out of the cache the same way a
truncated stream does.
Vertex and Gemini stay off the edge. litellm's `_check_custom_proxy` rewrites a
path-prefixed vertex api_base into `{api_base}:{endpoint}`, dropping project,
location and model, so a mount under a path prefix cannot work without a
root-mounted edge on its own port or a change in litellm. Shipping an
unvalidated URL guess would have been worse than saying so in PROVIDER_CACHE.md.
Also finishes the MountPolicy move: a mount now carries its signer and its
unkeyed headers together instead of a bare signer map.
The exact-request cache reused 5% of routed traffic (build 218: 19 hits,
350 misses) because every test salts its prompt with a fresh unique_marker(),
so the same test could never match itself across builds. It also routed only
openai and anthropic, while the week's flakiness was Bedrock.
Key is now HMAC(test id + method + URL + headers + body, with every
unique_marker() token replaced by a placeholder, + FIFO slot index). The slot
index is what keeps two marker-only-different calls in one test on two
recordings and therefore two provider response ids, so spend rows still
reconcile one per invocation. A call outside any test is not cacheable.
Bedrock gets a region-qualified mount and SigV4 re-signing, since the edge
rewrites the Host the proxy signed. Signature headers are excluded from the
key for signing mounts only, because x-amz-date would otherwise make every
Bedrock request a permanent miss; every other mount still keys on its
credentials whole. Only Anthropic-on-Bedrock chat deployments route:
embeddings, image generation, rerank and realtime keep their direct path, and
so do deployments carrying their own aws_role_name or static keys, whose whole
point is to prove the product's assume-role chain rather than the runner's.
The two eventstream actions bypass the cache and go live, still signed.
Counters are now attributed per mount as well as in total, so a build can
report a per-provider hit rate instead of one number.
The first cache-enabled litellm-e2e build (211) showed three gaps in the shared provider cache:
Every OpenAI response carries Cloudflare bot-management Set-Cookie headers, and the capture rejected any response with Set-Cookie, so no OpenAI response was ever recorded (179 of 372 misses rejected). The edge already withholds Set-Cookie from the proxy, so drop it before validating and storing instead of rejecting.
The provider prompt-caching tests need fresh provider state: a replayed priming response reports cache creation rather than a cache read, and the TPM test then trips the key limit. Mark both modules provider_live.
TestApiBaseSeam::test_live_mode_returns_none ran inside the cache-enabled runner and saw the shared edge; isolate it from E2E_PROVIDER_CACHE.
