* fix(mcp): drop caller host and configured upstream headers from logged metadata
The synthetic request that carries MCP client headers into
add_litellm_data_to_request forwarded the caller's Host header, and
Request.url is built from it, so a caller chose the proxy_server_request
url and the metadata endpoint that every logging callback records.
_upstream_credential_headers also only knew the configured client side
auth header and the x-mcp- prefix family, so a header name declared in
mcp_servers.<name>.extra_headers reached logging metadata in cleartext.
Those names are admin chosen, so no prefix rule can recognize them; read
them off the server registry instead. The header is still forwarded
upstream, which is what extra_headers is for. authorization is left out
because clean_headers already strips it and claiming it here would move
authenticated_with_header on the oauth passthrough config.
The Responses bridge tests stub the server manager, so their fakes gain
the registry accessor the sanitizer now reads.
* fix(mcp): drop caller host from the sanitized header mapping too
The synthetic request stopped forwarding host, but the parallel sanitizer
did not, so a forged hostname still reached the guardrail payload and the
list_tools spend row. Drop it there as well.
Exempt the configured identity headers from the upstream credential set.
get_user_from_headers resolves end user attribution off the same request
this module reconstructs, and it only fills end_user_id when auth left it
unset, so claiming user_header_name or a user_header_mappings name would
lose attribution on the MCP paths that authenticate upstream.
Drop the isinstance guard on extra_headers entries: the field is typed
list[str], so the check is dead and basedpyright scores it.
* fix(mcp): accept a bare user_header_mappings entry when exempting identity headers
get_internal_user_header_from_mapping and get_customer_user_header_from_mapping
both normalize a single mapping to a one element list, and config_settings.md
documents the key as a dict. Iterating the bare form yields its keys instead,
so the exemption silently matched nothing and an identity header also named in
an MCP server's extra_headers was dropped after all.
MCP tool calls run their guardrails against a throwaway LLM-shaped dict
built by `ProxyLogging._convert_mcp_to_llm_format`, not against the dict
the tool call is logged from. `@log_guardrail_information` therefore
appended `standard_logging_guardrail_information` to that throwaway
dict's metadata bucket, where `get_standard_logging_object_payload`
never saw it, so the Guardrails Monitor reported zero evaluations and
zero blocks for all MCP traffic.
Thread the request's `litellm_logging_obj` into `pre_call_tool_check`
and `_create_during_hook_task` and bridge the guardrail records onto it:
- Seed `data["litellm_logging_obj"]`, which unified guardrails read and
pass into `apply_guardrail`.
- Call `_sync_guardrail_info_to_logging_obj` in a `finally`, which is
what native guardrails need and what makes the block path work: a
blocked call raises straight out of `pre_call_tool_check`, so the
record has to be attached before the exception leaves the frame.
Only the guardrail evaluation records are copied. The synthetic
request's messages and tool arguments are deliberately left behind --
they can carry end-user data and nothing in the monitor needs them.
In `call_mcp_tool`, flush the failure handlers before
`post_call_failure_hook` so the `status="failure"` standard logging
object exists when `_ProxyDBLogger.async_post_call_failure_hook` writes
the spend-log row the monitor's "Total Blocked" counts. Both handlers
gate on `should_run_logging("sync_failure")` / `("async_failure")` and
then mark it, so the `@client` wrapper's own post-raise logging is a
no-op and nothing is double-counted -- the same pattern
`_fire_mcp_tool_call_logging` already uses for `isError=True`.
Threaded through every MCP tool entry point: the managed-server path,
the local-OpenAPI registry path, the legacy registry fallback, and the
Responses API's `_execute_tool_calls`.
* fix(mcp): expose client HTTP headers to logging callbacks and hooks
MCP protocol tool calls built a synthetic Request with only content-type, so metadata.headers reaching logging callbacks and guardrails was empty while /mcp-rest/tools/call exposed the full set. Rebuild the synthetic request from the connection's raw headers (shared with the sampling path), and pass sanitized headers to the pre-call hook, the MCP to LLM guardrail bridge and the Responses API MCP bridge. Credential headers stay masked and proxy key headers stripped.
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(mcp): strip custom proxy key and upstream MCP credential headers from logging copies
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* refactor(mcp): make client side auth header name accessor public
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(mcp): strip custom proxy key and client redaction opt-out from mcp headers
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(mcp): drop custom proxy key header in the synthetic request builder
Strips general_settings.litellm_key_header_name in build_synthetic_mcp_request so every caller, including sampling, is covered, and reverts passing general_settings into add_litellm_data_to_request on the tool call path since that also switches on enforced_params.
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
---------
Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: shivam <shivam@berri.ai>
MCP tool calling worked on /v1/chat/completions and /v1/responses but not on
/v1/messages. Those are the only two surfaces with an MCP gateway entry point,
so a litellm_proxy MCP reference reached Anthropic verbatim inside tools and the
API rejected the request with "Input tag 'mcp' found using 'type' does not match
any of the expected tags". The playground never surfaced this because it dropped
the reference before sending, and disabled the MCP selector for the endpoint.
Add the third entry point in anthropic_messages_handler, ahead of the provider
branch so it covers the native path and both bridges from one place. The gateway
expands the reference against the caller's own credentials and access control,
which is the whole point of routing it through litellm rather than handing the
url to the provider.
/v1/messages needs Anthropic's own tool shape, so transform_mcp_tool_to_anthropic_tool
joins the OpenAI chat and Responses transforms alongside it. The tool loop speaks
tool_use and tool_result rather than OpenAI tool_calls, and reuses the existing
FakeAnthropicMessagesStreamIterator to re-stream the result, the same pattern the
websearch interception already uses on this route. Argument extraction moves into
the shared extractor: an Anthropic tool_use block carries its arguments under
`input`, and reading only `arguments` failed silently, executing the tool with
every argument dropped.
On the frontend the request builder declared selectedMCPTools and never read it,
so no tools key was ever sent. Wire it through a shared block builder and add the
endpoint to MCP_SUPPORTED_ENDPOINTS, which is what greys the selector out.
Resolves LIT-4517
Resolves LIT-4518
The aggregate MCP tools/list absorbed every per-server failure (upstream 401/403/5xx, timeouts,
network errors) into that server contributing zero tools, making a broken upstream indistinguishable
from a healthy server with no tools; the single-server REST list masked the same failures as
{"tools": [], "error": null, "message": "Successfully retrieved tools"}
Phase 2 of the MCP error-handling framework (LIT-4419): the manager fetch hops now raise a
classified MCPServerListError (faults/list_outcomes.py: total classifier, frozen outcome values)
instead of returning [], and each boundary applies the relay-vs-absorb policy matrix. The aggregate
keeps serving the healthy subset but records each server's outcome, surfaced on the tools/list
result _meta under litellm.ai/server_outcomes (the SDK passes a ListToolsResult through unwrapped)
and in spend logs as per_server_list_outcomes. Single-server REST requests relay truthful statuses
(unreachable/upstream_error 502, timeout 504, internal 500) and access denials now surface as real
403s instead of 200 unexpected_error bodies; upstream 403s surface through MCPUpstreamAuthError
like 401s. Outcome wire values carry category and status code only, never upstream prose
Resolves LIT-4421
When a /responses request uses a hosted MCP tool (server_url: litellm_proxy/<label>)
with store=true and the model calls a tool, the gateway auto-executes the tool and
streams one logical response stitched from several upstream responses: an interim
response whose only output is the function_call, then the post-tool answer
B1 (correctness): every streamed event was pinned to the first round's response id,
i.e. the interim response that carries the function_call but no tool output. The
client then continued the next turn from that dangling response and the provider
rejected it with "No tool output found for function call <id>", which on the
streaming path surfaced as a silent empty completion. The fix adopts each
auto-execute round's own response id (the cached id is reset when a follow-up round
starts) so the client continues from the final round, whose stored input chain
includes the function_call_output
B2 (robustness): initial and follow-up call failures were swallowed; the stream
emitted the mcp_list_tools discovery events and then closed with HTTP 200 and no
output and no error. The fix stashes the failure, makes the initial call eagerly in
aresponses_api_with_mcp so a pre-stream failure re-raises as a real 4xx before any
SSE bytes are written, and emits a terminal error event when a follow-up call fails
mid-stream
Adds regression tests covering continuation exposing the final round's response id
rather than the interim tool-call id, a follow-up failure emitting a terminal error
event, and an initial-call failure being stashed for eager re-raise
* fix(mcp): resolve tool name prefix via known server prefixes, not string match
When an MCP server's alias differs from its server_name, tool names are
listed with the alias prefix but _execute_tool_calls compared that prefix
against the server_name stored in tool_server_map. The mismatch silently
skipped prefix stripping, forwarding the fully-prefixed tool name upstream
and causing "Unknown tool" failures. Resolve the actual MCPServer object
and strip using its known prefix forms (alias, server_name, server_id)
instead.
* fix(mcp): preserve tool overrides and scope REST tool listing
Return saved tool display/description overrides from the server table API
so the edit UI reloads them, resolve display names before prefix stripping
on tool calls, and honor mcp_server_name and toolset_name filters on the
REST tools list endpoint.
Co-authored-by: Cursor <cursoragent@cursor.com>
* fix(mcp): inject BYOK credentials on Playground OpenAPI tool calls
Playground and Responses API route MCP execution through call_tool, which
skipped BYOK lookup and never set the OpenAPI auth ContextVar, so upstream
calls went out unauthenticated despite a stored user credential.
Co-authored-by: Cursor <cursoragent@cursor.com>
* test(mcp): cover alias-mismatch prefix stripping and display-name reverse mapping
Regression tests for _execute_tool_calls: an MCP server whose alias differs
from its server_name must still have its tool-name prefix stripped correctly,
and a tool called by its configured display name must resolve back to the
original tool name before dispatch.
* fix(mcp): validate tool display names against Bedrock's tool-name pattern
A display name replaces the tool name sent to the LLM provider, so a value
with spaces or other special characters saves successfully but fails every
subsequent Bedrock tool call. Validate tool_name_to_display_name server-side
(create/update payload) against Bedrock's [a-zA-Z0-9_-]+ constraint, and add
matching inline validation plus a save-blocking guard in the Admin UI's
create and edit MCP server forms.
* style(mcp): fix ruff/prettier formatting on CI
No logic changes; satisfies the format checks flagged on PR #32320.
* fix(mcp): fix CI failures on PR - complexity budget and stale test mock
Extract toolset-scope resolution and query-param normalization out of
list_tool_rest_api into helpers to bring it back under the C901 complexity
budget (was 18, now within the 15 threshold).
Add the missing get_mcp_server_by_name stub to the streaming iterator test's
mock manager; the alias-fallback resolution added for tool-name-prefix
stripping calls it unconditionally when _get_mcp_server_from_tool_name misses.
* test(mcp): cover BYOK OpenAPI auth-header helpers to close codecov patch gap
_format_byok_openapi_auth_header, _openapi_forwarded_extra_headers, and
_resolve_byok_mcp_auth_header were only exercised indirectly via a mocked
call_tool test, leaving their branches (auth-type formatting, header
forwarding/stripping, missing-credential 401) uncovered.
* fix(mcp): resolve BYOK auth before queuing the during-hook task
_resolve_byok_mcp_auth_header can raise a 401 when no credential is stored.
Resolving it after during_hook_task was already queued meant a hook's
side effects (audit logging, rate-limit bookkeeping) could run and record
success for a tool call that then fails on the missing credential.
* fix: correct mcp alias routing regressions
---------
Co-authored-by: Cursor <cursoragent@cursor.com>
MCPEnhancedStreamingIterator only auto-executed one round of MCP tool calls.
When a model retried a tool (e.g. after an error) in its follow-up turn, that
second tool call was streamed but never executed, and the response ended with
no final text. Route follow-up calls back through the same completion-check
phase as the initial response, so further tool-call rounds are handled the
same way, capped at MAX_MCP_TOOL_CALL_ROUNDS to avoid an unbounded loop.
* fix(mcp): roll up MCP tool spend to user counters and usage UI
Direct REST MCP tool calls now fire success logging so spend_logs and
user/team rollups include configured mcp_server_cost_info charges.
Co-authored-by: Cursor <cursoragent@cursor.com>
* fix(mcp): gate key-info enrichment to requests missing user_id; fix import order
- Only call _enrich_failure_metadata_with_key_info when user_api_key_user_id is
absent, avoiding a cache/DB lookup on every normal LLM request.
- Move LiteLLMProxyRequestSetup import to correct alphabetical position (I001).
Co-authored-by: Cursor <cursoragent@cursor.com>
* fix(mcp): scope MCP spend aggregate by api_key to prevent cross-tenant disclosure
Add api_key = ANY($2) to the MCP session aggregate query so it is
bounded by the same ownership already applied to the main page query.
Co-authored-by: Cursor <cursoragent@cursor.com>
* Fix spend logs for call and list mcp tools
* Add tags in mcp logging
* Fix ruff
* fix(lint): replace List/Dict with list/dict in new annotations (UP006)
Replace the 8 new UP006 violations introduced by the mcp-tags changes:
- Optional[List[str]] → Optional[list[str]] for request_tags params
- List[str] return type → list[str] in _get_parent_request_tags
- Dict[str, Dict[...]] → dict[str, dict[...]] for mcp_spend_map annotation
Co-authored-by: Cursor <cursoragent@cursor.com>
* fix(lint): keep call_tool_rest_api within complexity budget and narrow MCP spend enrichment except to PrismaError
* fix(mcp): keep final streaming chunk when draining inner stream fails
* fix: handle MCP logging edge cases
* fix: propagate MCP logging cancellation
---------
Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
* Litellm ishaan march23 - MCP Toolsets + GCP Caching fix (#25146)
* feat(mcp): MCP Toolsets — curated tool subsets from one or more MCP servers (#24335)
* feat(mcp): add LiteLLM_MCPToolsetTable and mcp_toolsets to ObjectPermissionTable
* feat(mcp): add prisma migration for MCPToolset table
* feat(mcp): add MCPToolset Python types
* feat(mcp): add toolset_db.py with CRUD helpers for MCPToolset
* feat(mcp): add toolset CRUD endpoints to mcp_management_endpoints
* fix(mcp): skip allow_all_keys servers when explicit mcp_servers permission is set (toolset scope fix)
* feat(mcp): add _apply_toolset_scope and toolset route handling in server.py
* fix(mcp): resolve toolset names in responses API before fetching tools
* feat(mcp): add mcp_toolsets field to LiteLLM_ObjectPermissionTable type
* feat(mcp): register LiteLLM_MCPToolsetTable in prisma client initialization
* feat(mcp): validate mcp_toolsets in key-vs-team permission check
* feat(mcp): register toolset routes in proxy_server.py
* feat(mcp): add MCPToolset and MCPToolsetTool TypeScript types
* feat(mcp): add fetchMCPToolsets, createMCPToolset, updateMCPToolset, deleteMCPToolset API functions
* feat(mcp): add useMCPToolsets React Query hook
* feat(mcp): add toolsets (purple) as third option type in MCPServerSelector
* feat(mcp): extract toolsets from combined MCP field in key form
* feat(mcp): extract toolsets from combined MCP field in team form
* feat(mcp): show toolsets section in MCPServerPermissions read view
* feat(mcp): pass mcp_toolsets through object_permissions_view
* feat(mcp): add MCPToolsetsTab component for creating and managing toolsets
* feat(mcp): add Toolsets tab to mcp_servers.tsx
* feat(mcp): pass mcpToolsets to playground chat and responses API calls
* feat(mcp): generate correct server_url for toolsets in playground API calls
* docs(mcp): add MCP Toolsets documentation
* docs(mcp): add mcp_toolsets to sidebar
* fix(mcp): replace x-mcp-toolset-id header with ContextVar to prevent client forgery
* fix(mcp): use ContextVar + StreamingResponse for toolset MCP routes (fixes SSE streaming)
* fix(mcp): cache toolset permission lookups to avoid per-request DB calls
* test(mcp): add tests for toolset scope enforcement, ContextVar isolation, and access control
* fix(mcp): cache toolset name lookups in MCPServerManager to avoid per-request DB calls
* fix(mcp): prevent body_iter deadlock + use cached toolset lookup in responses API
- _stream_mcp_asgi_response: add done callback to handler_task that puts
the EOF sentinel on body_queue when the task exits, preventing body_iter
from hanging forever if the handler raises after headers are sent.
- litellm_proxy_mcp_handler: replace raw get_mcp_toolset_by_name() DB call
with global_mcp_server_manager.get_toolset_by_name_cached() so toolset
resolution uses the 60s TTL cache added for this purpose instead of
hitting the DB on every responses-API request.
* fix(mcp): toolset access control, asyncio fix, and real unit tests
- server.py: _apply_toolset_scope now enforces that non-admin keys must
have the requested toolset_id in their mcp_toolsets grant list;
admin keys always bypass the check.
- mcp_management_endpoints.py: three access-control fixes:
* fetch_mcp_toolsets: non-admin keys with mcp_toolsets=None now
return [] instead of all toolsets (only admins get 'all' when
the field is absent)
* fetch_mcp_toolset: non-admin keys that haven't been granted the
requested toolset_id now get 403 instead of the full result
* add_mcp_toolset: duplicate toolset_name now returns 409 Conflict
instead of an opaque 500
- proxy_server.py: use asyncio.get_running_loop() instead of
get_event_loop() inside an already-running coroutine (Python 3.10+).
- test_mcp_toolset_scope.py: replace four hollow tests that only
asserted local variable properties with real tests that call the
production fetch_mcp_toolsets() and handle_streamable_http_mcp()
functions with mocked dependencies.
* fix(mcp): add mcp_toolsets to ObjectPermissionBase, fix multi-toolset overwrite, fix delete 404, allow standalone key toolsets
* fix(mcp): add auth check on toolset resolution in responses API; union mcp_servers in _merge_toolset_permissions
* fix(mcp): handle RecordNotFoundError in update_mcp_toolset; union direct servers with toolset servers
* fix(mcp): use _user_has_admin_view; deny None mcp_toolsets for non-admin; use direct RecordNotFoundError import; fix docstring
* fix(mcp): add @default(now()) to MCPToolsetTable.updated_at; fix test for non-admin toolset access
* fix: use UniqueViolationError import; guard _ensure_eof for error/cancel only
* fix(mcp): preserve mcp_access_groups in toolset scope, use shared Redis cache for toolset perms
- Remove mcp_access_groups=[] from _apply_toolset_scope (server.py) and the
responses API toolset path (litellm_proxy_mcp_handler.py). A key's access-group
grants remain valid even when the request is scoped to a single toolset; clearing
them silently revoked legitimate entitlements.
- Switch resolve_toolset_tool_permissions and get_toolset_by_name_cached to use
user_api_key_cache (Redis-backed DualCache in production) instead of per-instance
in-memory dicts. Cache entries are now shared across workers, eliminating the
per-worker stale-toolset-permission window flagged as a P1 by Greptile.
- Use union merge (set union of tool names per server) when applying toolset
permissions in the responses API path so direct-server tool restrictions are not
overwritten by toolset permissions.
* fix(mcp): return 404 when edit_mcp_toolset target does not exist
* fix(mcp): align mcp_toolsets default to None in LiteLLM_ObjectPermissionTable
* fix(mcp): admin toolset visibility, in-place tool name mutation, test helper coercion
* fix(mcp): treat None/[] team mcp_toolsets as no restriction in key validation
* fix(mcp): allow_all_keys backward compat, blocked_tools API write-path, efficient startup query
* fix(mcp): use _mcp_active_toolset_id ContextVar to detect toolset scope, avoiding DB-default false-positive
* fix(mcp): remove dead toolset cache stubs, log invalidation failures, align schema updated_at defaults
* fix(mcp): deserialise MCPToolset from Redis cache hit, replace fastapi import in test
* fix(mcp): evict name-cache on toolset mutation, 409 on rename conflict, warning-level list errors
* fix(redis): regenerate GCP IAM token per connection for async cluster (#24426)
* fix(redis): regenerate GCP IAM token per connection for async cluster clients
Async RedisCluster was generating the IAM token once at startup and
storing it as a static password. After the 1-hour GCP token TTL, any
new connection (including to newly-discovered cluster nodes) would fail
to authenticate.
Fix: introduce GCPIAMCredentialProvider that implements redis-py's
CredentialProvider protocol. It calls _generate_gcp_iam_access_token()
on every new connection, matching what the sync redis_connect_func
already does. async_redis.RedisCluster accepts a credential_provider
kwarg which is invoked per-connection.
* refactor(redis): move GCPIAMCredentialProvider to its own file
Extract GCPIAMCredentialProvider and _generate_gcp_iam_access_token
into litellm/_redis_credential_provider.py. _redis.py imports them
from there, keeping the public API unchanged.
* fix: address Greptile review issues
- GCPIAMCredentialProvider now inherits from redis.credentials.CredentialProvider
so redis-py's async path calls get_credentials_async() properly
- move _redis_credential_provider import to top of _redis.py (PEP 8)
- remove dead else-branch that silently no-oped (gcp_service_account from
redis_kwargs.get() was always None since it's popped by _get_redis_client_logic)
- remove mid-function 'from litellm import get_secret_str' inline import
- remove unused 'call' import from test_redis.py
* chore: retrigger CI/review
* chore: sync schema.prisma copies from root
* chore: sync schema.prisma copies from root
* fix(proxy_server): use bounded asyncio.Queue with maxsize to prevent unbounded growth
* fix(a2a/pydantic_ai): make api_base Optional to match base class signature
* fix(a2a/pydantic_ai): make api_base Optional in handler and guard against None
* fix(mcp): remove unused get_all_mcp_servers import
* fix(mcp): remove unused MCPToolset import
* refactor(mcp): extract toolset permission logic to reduce statement count below PLR0915 limit
* fix(tests): update reload_servers_from_database tests to mock prisma directly
---------
Co-authored-by: Ishaan Jaff <ishaanjaffer0324@gmail.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
* fix(toolset_db): lazy-import prisma to avoid ImportError when prisma not installed
* fix(tests): update UI tests for toolset tab and updated empty state text
* fix(tests): add get_mcp_server_by_name to fake_manager stub
---------
Co-authored-by: Ishaan Jaff <ishaanjaffer0324@gmail.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
The `if hasattr(...)` guards in test_acompletion_with_mcp_adds_metadata_to_streaming
and test_acompletion_with_mcp_streaming_metadata_in_correct_chunks could silently skip
the provider_specific_fields assertions if chunks lacked choices/delta. Replace with
unconditional `assert hasattr(...)` so failures surface immediately.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Fixes test failures that occur during parallel test execution (pytest -n 4)
due to module reloading issues with conftest.py reloading litellm.
Changes:
- Add module reload fixtures to ensure fresh references after conftest reloads
- Use patch.object and string-based patches instead of direct attribute assignment
- Use class name comparison instead of isinstance for reloaded modules
- Handle case where litellm is missing from sys.modules during parallel runs
- Move stream consumption inside patch contexts to avoid real API calls
- Mock litellm.acompletion instead of low-level HTTP handlers
- Add skipif decorator for enterprise-only test classes
Affected test files:
- test_container_integration.py
- test_responses_background_cost.py
- test_huggingface_embedding_handler.py
- test_vertex_ai_rerank_integration.py
- test_volcengine_responses_transformation.py
- test_pillar_guardrails.py
- test_litellm_pre_call_utils.py
- test_proxy_server.py
- test_converse_transformation.py
- test_chat_completions_handler.py
- test_aresponses_api_with_mcp.py
- test_anthropic_experimental_pass_through_messages_handler.py
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
1. test_acompletion_with_mcp_streaming_metadata_in_correct_chunks:
- Moved stream consumption inside patch context to avoid real API calls
- The previous implementation had assertions outside the `with patch(...)`
block, causing real OpenAI API calls when consuming the stream
2. TestCheckResponsesCost tests:
- Added skip condition when litellm_enterprise module is not available
- These tests import from litellm_enterprise.proxy.common_utils.check_responses_cost
which is only available in the enterprise version
