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.
