* fix(anthropic): drop and self-heal empty thinking blocks on /v1/messages
* test(anthropic): pin early-signature carry across the blank thinking chunk skip
* fix(anthropic): resolve /v1/messages effort tiers through the capability owner
The bridge normalizer read three supports_*_reasoning_effort booleans of its own, so it
answered "which levels does this deployment take" independently of the resolver behind
/model_group/info. The two disagreed: a proxy advertising kimi-k3 max forwarded high.
Degrade against resolve_supported_reasoning_efforts instead, with the chains as a declared
table. When no step of a chain is accepted, the fallback is read off that same resolved set
rather than assumed, since an entry naming its levels outright can exclude the tiers the
per-level flags treat as unconditional. none is never chosen as that fallback, being an off
switch rather than a tier, and a deployment accepting no tier at all keeps the floor every
deployment degraded to before.
* test(anthropic): pin the normalized effort at the /v1/messages request boundary
The existing coverage stopped at normalize_reasoning_effort_value, so nothing failed if the
handler dropped or overwrote the normalized tier on its way into completion_kwargs. Drive
_prepare_completion_kwargs instead and assert on the kwargs handed to acompletion, in both the
string and the dict effort shapes, including the provider-prefixed model name the handler is
actually called with.
Against the pre-fix normalizer the fallback case fails, and against the baseline before a map
entry could declare its levels 7 of the 12 fail, so the boundary is pinned rather than restated.
The /v1/messages bridge decided a Claude target could take `reasoning_effort` from
the model name, which says nothing about the params the provider in front of it
accepts. Snowflake serves Claude over the Anthropic dialect and declares `thinking`
alone, so `get_optional_params` raised `UnsupportedParamsError` before the request
reached the wire: every adaptive request carrying an effort tier turned a 200 into
a 400 for all seven of its Claude entries.
The tier is now offered only where the target declares the param, reading the same
`get_supported_openai_params` the sibling `_supports_prompt_cache_key` reads twelve
lines up. A target declaring neither carrier keeps its bare `thinking` block, which
is what this bridge sent before it carried a tier at all.
Without a resolved provider the tier stays behind rather than being offered blind.
Resolving one from the model's prefix instead would run an OAuth device flow for
github_copilot and chatgpt, blocking for minutes, and one of the two callers in that
position is a logging callback. The copilot case is pinned by a test.
/v1/messages forwarded `thinking` verbatim for a Claude-family model and then returned,
carrying `output_config.effort` only when the model string started with a Bedrock prefix.
Every other bridged provider got a bare adaptive thinking block, so the caller's effort did
nothing: max and minimal produced byte-identical upstream bodies.
Send those targets the tier as `reasoning_effort`, which is the param they take. Bedrock keeps
taking `output_config`, since the two are not interchangeable there: an application inference
profile ARN resolves to no chat config, so `reasoning_effort` is dropped and the tier vanishes,
and a provider that rebuilds `output_config` from it overwrites a caller-set `thinking.display`
on the way. The tier stays a plain string, the summary already travelling inside the forwarded
`thinking` block. Adaptive with no tier, and budgeted thinking, both stay exactly as they were.
Kimi K3 accepts exactly low, high and max, defaults to max, and always thinks.
The map could not say that: medium and high have no supports_*_reasoning_effort
flag because every other reasoning model takes them, so the ten kimi-k3 entries
carried supports_reasoning alone and resolved to unknown. The dashboard then fell
back to a capability-blind level list that deliberately omits max, which is why a
kimi-k3 tier cannot be set to max thinking today.
Add reasoning_effort_levels, an array key in the shape the map already uses for
supported_endpoints and supported_modalities. Where present it is read first and
wins whole; every other entry keeps answering through the per-level flags,
unchanged. It is deliberately a different name from the computed
ModelGroupInfo.supported_reasoning_efforts, which stays derived from a group's
deployments and is never seeded from one deployment's model_info.
The levels are per entry rather than per model, because the deployments differ:
Moonshot, Together, Fireworks and Azure Foundry all forward the level unchanged
and get the model's own low/high/max, while Perplexity documents a six-value
enum it maps down internally and gets that. The /v1/messages degradation chain
consults the same declaration, so the level the map advertises is the level that
path forwards.
For non-Anthropic models served over /v1/messages, the outer wrapper recomputes
cost over the adapter-translated Anthropic response dict. That dict dropped every
web search usage signal, so the recompute overwrote the correct cost breakdown
with a token-only one: x-litellm-response-cost-tool-usage read 0.0 and
x-litellm-response-cost-original excluded the search cost, while the total kept it.
The adapter now maps web search request counts (from Usage.server_tool_use or
Gemini's prompt_tokens_details) into usage.server_tool_use.web_search_requests,
matching the Anthropic API shape, and the Gemini web search cost calculator falls
back to server_tool_use when prompt_tokens_details carries no count. The shared
get_web_search_requests helper is now public since five modules consume it.
Resolves LIT-6288
Now that /v1/messages routes provider failures through exception_type, an
Anthropic permission_error fell through the anthropic branch to the generic
APIConnectionError and reached the client as a 500 where the raw exception
used to answer 403. Map 403 to PermissionDeniedError so the status survives
on every route.
The router's pre-content ping filter dropped AgenticAnthropicStreamingIterator's
hold-back keepalive, so a held-back turn sent the client nothing until the buffer
settled. A ping that no lifecycle frame precedes is now forwarded live, since a
fallback's message_start can still follow it without overlapping lifecycles
The proxy's cancel-refund guard checked isinstance against the iterator, but the
proxy only ever sees it behind FallbackAwareAnthropicMessagesStream and
AnthropicMessagesStreamingResponse, so a disconnect during hold-back refunded the
budget reservation anyway. Both wrappers now forward a duck-typed
has_buffered_provider_output flag, and the router wrapper follows a fallback
source so the flag tracks the stream actually being consumed
* perf(streaming): add shared JSONFragmentAccumulator for Vertex and Anthropic
Vertex's handle_accumulated_json_chunk and Anthropic's
_handle_accumulated_json_chunk each independently accumulated SSE fragments
into a JSON envelope with self.accumulated_json += fragment. Because the
attribute holds a live reference, CPython copies the whole prior buffer on
every fragment, making buffer assembly O(n^2) in total payload size.
Anthropic additionally had no completeness heuristic at all and called
json.loads on the whole buffer after every fragment, and could wedge forever
on two concatenated envelopes.
Add JSONFragmentAccumulator in litellm_core_utils/: fragments append to a
list in O(1), a could_close_json heuristic lets callers skip the join+parse
entirely until a value could plausibly be complete, and pop_next_value peels
one JSON value off the front of the buffer at a time using
json.JSONDecoder().raw_decode, keeping any unconsumed remainder instead of
failing on concatenated values. Migrate both providers onto it; Anthropic's
__next__/__anext__ end-of-stream handlers now delegate to
_handle_accumulated_json_chunk(is_final=True) instead of duplicating the
parse-and-reset logic inline.
Fixes#31861.
* test(streaming): close diff-coverage gaps in JSONFragmentAccumulator migration
Codecov flagged 11 uncovered lines in the migration: the accumulated_json
setter, __next__/__anext__'s end-of-stream drain branches in both providers,
and the pop_next_value "not found" path when a buffer's newest fragment ends
in "}" but is genuinely incomplete (an inner object closed, the outer one
didn't). Add targeted tests for each.
* fix(streaming): make JSONFragmentAccumulator's completeness heuristic O(1)
could_close_json rescanned every preceding blank fragment on each call, so a
hostile upstream that sends malformed JSON (never closing) followed by many
blank keepalive fragments could drive that scan, and the join+parse it
gates, to O(n^2) total. Track the last non-blank fragment's trailing byte
incrementally in append/pop_next_value/set instead of rescanning the buffer.
Reported by automated review on PR #36610.
* fix(streaming): make JSONFragmentAccumulator.pop_next_value O(1) per call
pop_next_value previously rebuilt the full remaining string and sliced a
new remainder on every call, so draining N concatenated JSON values
already sitting in one buffer cost O(n^2) total. Replace the rebuild-and-
slice with a materialize-once cursor: pending fragments are joined into
the buffer only when new ones have arrived since the last pop, and
consumed values are dropped by advancing an offset instead of copying
the remaining string.
* test(streaming): make JSONFragmentAccumulator drain regression test CI-stable
The 80k-value drain test used an absolute ms budget that flaked on a
busier CI runner (233.5ms vs a 150ms budget calibrated on a quiet
machine). Replace it with a doubling-ratio check: draining twice as many
concatenated values should take roughly 2x as long for O(n), not
~4x for O(n^2), and that ratio holds regardless of machine speed.
* test(streaming): suppress TQ002 on the append-laziness spy test
A test-quality gate (TQ002: don't assert only that a mock was called)
landed upstream since this branch's last rebase and now flags
test_append_never_calls_raw_decode. The test verifies append() defers
all decoding to pop_next_value, which has no caller-observable proxy
other than spying on the stdlib call it must avoid making.
* test(vertex): spy on raw_decode instead of json.loads in accumulator regression tests
Post-migration to the shared JSONFragmentAccumulator, Vertex's decode
path goes through json.JSONDecoder.raw_decode, not json.loads. The two
O(n^2)/partial-fragment regression tests still patched json.loads, which
that path never calls, so both passed unconditionally regardless of
whether the underlying implementation regressed. Verified by simulating
an eager-reparse regression: both tests now fail against it and pass
against the correct implementation.
* fix(streaming): widen JSONFragmentAccumulator's whitespace skip to match str.strip()
pop_next_value's whitespace skip only matched json.decoder.WHITESPACE's
ASCII set, narrower than str.strip() (Unicode-aware) which the O(1)-cursor
rewrite replaced. A non-ASCII separator like U+00A0 between two
concatenated JSON values on one SSE line made raw_decode fail on it, and
the buffer never advanced past that byte again, permanently stranding
everything after it for the rest of the stream. Use str.isspace() to
match str.strip()'s tolerance.
---------
Co-authored-by: Deepanshu <deepanshu.lulla@alpha-sense.com>
anthropic_messages goes through _ageneric_api_call_with_fallbacks rather
than _acompletion, so its returned streaming iterator was never wrapped
by the chat-completions fallback handler. A retriable SSE event: error
frame (overloaded_error, internal_server_error) from a native
Anthropic/Bedrock passthrough passed through to the client unchanged,
and a MidStreamFallbackError raised by the completion-bridge path's
CustomStreamWrapper propagated unhandled.
Add _aanthropic_messages_streaming_iterator, mirroring
_acompletion_streaming_iterator: it detects a retriable SSE error event
via the new parse_anthropic_error_event helper, raises
MidStreamFallbackError once real generated content (a content_block_delta
frame) has not yet reached the caller, and re-enters the Router's
fallback chain. A MidStreamFallbackError raised directly by the source
iterator (the completion-bridge path) is gated the same way via its own
is_pre_first_chunk flag. The raised MidStreamFallbackError carries a
status-coded original_exception built from the parsed error type, so
status_code/cooldown logic sees the real 429/500/503/etc. instead of a
hardcoded 503.
Lifecycle/bookkeeping frames (message_start, content_block_start, ping,
...) never disqualify a fallback attempt by themselves, since Anthropic
routinely sends message_start before an overload error - but they are
buffered rather than forwarded immediately, since forwarding one and
then appending a fallback attempt's own message_start would produce two
overlapping message lifecycles on one SSE stream. Buffered frames flush,
in order, once real content arrives or the stream ends without error.
Once real content has streamed, or the error is a non-retriable 4xx, the
chunk (or exception) is forwarded as-is rather than starting a second
lifecycle. Content and error coalesced into a single physical read are
handled the same way: once the client has genuinely received the content
(bundled in that same forwarded chunk), no fallback is attempted. A
`ping` keepalive is dropped outright before any real content arrives
(it recurs indefinitely on a slow-starting connection and carries
nothing worth buffering), and the pre-content lifecycle buffer is capped
at MAX_BUFFERED_PRE_CONTENT_ANTHROPIC_CHUNKS, forcing an early commit to
the primary stream so a hostile or pathological upstream can't grow it
without bound. is_anthropic_ping_chunk only matches a chunk whose every
event: line is event: ping, so a ping coalesced with real content or a
retriable error into one physical transport chunk is never dropped.
The fallback request kwargs also deep-copy nested litellm_metadata/metadata
(matching the Responses API path) so the primary attempt's
deployment-specific fields never leak into the fallback request, and the
fallback deployment's own provider headers are merged onto the wrapper's
_hidden_params so they still reach the client/logging pipeline. A
fallback that resolves to a non-streaming response (e.g. an agentic
tool-use interception loop) is synthesized into a real Anthropic SSE
event sequence via the new anthropic_messages_response_as_sse_events
helper, instead of yielding a raw dict into the byte stream - including
a trailing signature_delta for a thinking block, and a message_start
whose stop_reason/stop_sequence/output_tokens stay null/zero the way a
real stream's does instead of leaking the completed response's final
state.
Resolves#24004
Read strict from the caller's output_format/output_config.format instead
of hardcoding true, defaulting to false to match OpenAI's API default.
Explicit true/false values are preserved and output_format still takes
precedence over output_config.format.
* fix(anthropic): reconcile enum with declared type in output_format schema
Anthropic cross-validates `enum` against `type` in structured outputs: every
enum value must match a single declared type. A union `type` array, or an enum
value whose JSON type differs from a scalar `type`, is rejected with
"Invalid schema: Enum value 'low' does not match declared type '['string','null']'"
filter_anthropic_output_schema had no enum/type reconciliation, so both keys
reached Anthropic untouched. Drop the conflicting `type` -- `enum` is the
tighter constraint, and an enum with no `type` is accepted
The drop is conditional: `type` is only removed when it is a union array, or
when some enum value does not match the scalar type. A matching enum plus
scalar `type` is left exactly as-is, so existing behaviour is unchanged
Pydantic emits the failing shape for Optional[SomeEnum], so this affects any
caller with a nullable enum field on the native output_format path. vertex_ai
is unaffected because it is forced onto the permissive tool-use path
Fixes#37881
* refactor(anthropic): make enum/type reconciliation immutable and precisely typed
Address review: the predicate registry was a mutable `dict[str, Any]`, and the
reconciliation removed `type` by mutating the built result with `pop`
- registry is now `Final[Mapping[str, Callable[[Any], bool]]]` wrapped in
`MappingProxyType`, so predicate signatures are statically checked and the
table cannot be mutated
- the conflict decision moves into a pure helper evaluated once against the
input schema, and the conflicting `type` key is skipped at build time in the
existing loop instead of being popped afterwards, so nothing is mutated
Behaviour is unchanged; all 27 tests in the schema-filter suite still pass
