* fix(anthropic, mcp): sanitize tool names to match Anthropic's `^[a-zA-Z0-9_-]{1,128}$`
Tool names with characters like `/` or `.` (commonly produced by the
OpenAPI -> MCP generator from `operationId`s such as
`actions/download-job-logs-for-workflow-run`) caused Anthropic to reject
requests with `tools.N.custom.name: String should match pattern
'^[a-zA-Z0-9_-]{1,128}$'`.
Two layers of fix:
1. Anthropic transformation: build a per-request forward map (original ->
sanitized, disambiguated by suffix on collisions) and a reverse map
(only for names actually rewritten). Forward map is applied to tool
defs, `tool_choice`, and historical assistant tool_calls in messages.
Reverse map is threaded through both the non-streaming and streaming
response paths so callers continue to see their original tool names
in `tool_use` blocks.
2. OpenAPI -> MCP generator: sanitize `operationId` (and the
method+path fallback) at registration time so generated MCP tools are
valid for any strict-name provider, not just Anthropic. The dashboard
preview endpoint applies the same sanitization for parity.
Includes unit tests covering: collision disambiguation between
`foo_bar` and `foo/bar` in the same request, reverse-map only firing
for actually-rewritten names, message rewrite for historical tool_calls,
streaming chunk_parser reverse-mapping, and sanitization of OpenAPI
operationIds plus the preview endpoint output.
Made-with: Cursor
* fix(anthropic): build tool-name maps in transform_request, not optional_params
The previous patch stashed the per-request forward and reverse tool-name
maps under ``optional_params["_anthropic_tool_name_forward_map"]`` and
``optional_params["_anthropic_tool_name_map"]``. ``optional_params`` is
the dict that becomes the JSON body via ``data = {**optional_params}``,
so those internal keys leaked over the wire and Anthropic 400'd with:
_anthropic_tool_name_forward_map: Extra inputs are not permitted
Worse, this meant *every* request whose tool list contained any name with
an invalid character (the exact case the patch was meant to fix) regressed
into a confusing meta-error pointing at LiteLLM's internal map instead of
the offending tool.
Fix: move all tool-name sanitization into ``transform_request``, which is
the single chokepoint already shared by ``AnthropicConfig``,
``AmazonAnthropicConfig`` (Bedrock invoke), ``VertexAIAnthropicConfig``,
and ``AzureAnthropicConfig`` (all call ``super().transform_request`` /
``AnthropicConfig.transform_request(self, ...)``). New static helper
``_sanitize_tool_names_in_request`` walks the already-Anthropic-shaped
``optional_params["tools"]`` (only ``type=="custom"`` entries -- hosted
tool names are reserved by Anthropic and must not be touched), builds
the per-request forward/reverse maps, and applies the forward map in
place to ``tools[*].name`` and ``tool_choice.name``. The reverse map is
stashed exclusively on ``litellm_params`` (which is never serialized to
a provider) under ``_anthropic_tool_name_map`` for the response paths
to consume.
Side effect of this restructure: ``map_openai_params`` is now a pure
OpenAI->Anthropic param translator with no side-channel state, which
matches its contract everywhere else in the codebase.
Tests: replaced the now-incorrect "stashes maps in optional_params"
tests with regressions that assert no underscore-prefixed keys appear
in either ``optional_params`` after ``map_openai_params`` or in the
final ``transform_request`` body. Added end-to-end coverage for:
sanitization in ``transform_request``, ``tool_choice`` rewriting,
historical ``tool_calls`` rewriting in messages, and hosted-tool
passthrough.
Made-with: Cursor
* fix(anthropic): always sanitize empty text content blocks
Anthropic 400s on `{"role": "user", "content": ""}` with:
"messages: text content blocks must be non-empty"
LiteLLM already had `_sanitize_empty_text_content` to rewrite empty text
to a placeholder, but it was gated behind `litellm.modify_params=True`.
With that flag off (default), empty content from upstream agent
frameworks (e.g. pydantic-ai) flowed straight through and tripped the
Anthropic validator.
Fix:
- Always run `_sanitize_empty_text_content` at the top of
`anthropic_messages_pt`, independent of `modify_params`. There is no
way to "pass through" an empty text block, so this is non-optional.
The richer tool-call sanitizations (Cases A/B/D, which actually
mutate conversation structure) remain gated on `modify_params`.
- Extend `_sanitize_empty_text_content` to also handle list-of-blocks
content (`[{"type": "text", "text": ""}]`), not just string content.
Adds 3 regression tests covering string content, list-of-blocks
content, and the no-op case (non-empty messages with modify_params off).
Made-with: Cursor
* fix(anthropic): drop dead tool-name forward-map params, fix mypy + caller-mutation
- remove unused `name_forward_map` param from `_map_tool_choice`,
`_map_tool_helper`, `_map_tools` and the `_apply_anthropic_tool_name_forward`
helper. Production sanitization runs in `_sanitize_tool_names_in_request`
at `transform_request`; these params were never threaded through.
- handler.py: use `ANTHROPIC_TOOL_NAME_REVERSE_MAP_KEY` constant instead of
the hardcoded `"_anthropic_tool_name_map"` string.
- fix mypy `"object" has no attribute "__iter__"` in
`_rewrite_tool_names_in_messages` by guarding `tool_calls` with
`isinstance(..., list)`.
- `_sanitize_tool_names_in_request`: build a new tools list with copy-on-
change entries (and copy `tool_choice` on rewrite) so a caller reusing
the same tool list/dicts across requests doesn't see its inputs
permanently rewritten.
- doc-comment `_build_request_tool_name_maps` clarifying it operates on
OpenAI-format tools (vs `_sanitize_tool_names_in_request` which runs
on Anthropic-format tools post-`_map_tools`).
- tests: drop 3 tests pinning the now-removed param paths; add coverage
for tool_calls + None function_call rewrite and caller-dict immutability.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* fix(mcp): inherit stored credentials in test/tools/list for edit flow
When editing an existing MCP server, the Tool Configuration preview
calls POST /mcp-rest/test/tools/list with server_id but no credentials
(management API redacts them). The endpoint now calls
_inherit_credentials_from_existing_server() so stored bearer tokens
and OAuth2 M2M credentials are loaded from global_mcp_server_manager
automatically — tools load without re-entering credentials.
New servers (no server_id) and requests with explicit credentials are
unaffected (function is a no-op in both cases).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* fix(mcp): show all tools in edit panel, not just allowed tools
Edit flow was passing externalTools (from GET /tools/list, filtered by
allowed_tools) to MCPToolConfiguration, disabling the internal hook.
Remove the external props so the internal hook fires via
POST /test/tools/list, which returns all tools unfiltered. Combined
with the credential inheritance fix, tools load automatically without
re-entering credentials and all tools are visible for re-configuration.
existingAllowedTools still pre-checks previously allowed tools.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* Fix order-dependent collision in _build_anthropic_tool_name_maps
Use a two-pass approach: first pre-register all already-valid tool names
in the 'used' set, then sanitize/disambiguate names that need rewriting.
This ensures valid names always have priority regardless of input order,
preventing duplicate tool names on the wire when e.g. 'foo/bar' appears
before 'foo_bar' in the tool list.
Add regression test for the reversed ordering case.
* Fix OpenAPI tool name collision: disambiguate sanitized names with numeric suffixes
sanitize_openapi_tool_name replaces all invalid chars with '_', but when
two operationIds differ only by sanitized characters (e.g. 'foo/list' and
'foo.list' both become 'foo_list'), the second registration silently
overwrites the first in the tool registry.
Add collision disambiguation in register_tools_from_openapi that appends
_2, _3, ... suffixes when a sanitized name is already taken, mirroring
the existing logic in _build_anthropic_tool_name_maps.
* Fix preview endpoint missing collision disambiguation for tool names
Add used_names tracking and _2/_3 suffix disambiguation to
_preview_openapi_tools, matching the logic in register_tools_from_openapi.
Without this, two operationIds that sanitize to the same string (e.g.
'foo/list' and 'foo.list' both becoming 'foo_list') would show duplicate
names in the preview while registration would disambiguate them.
* Align preview HTTP method order with register_tools_from_openapi
The preview endpoint and register_tools_from_openapi both use
order-dependent collision disambiguation (_2, _3 suffixes). When the
iteration order differs, two operations on the same path with sanitized
names that collide get different suffixes in preview vs registration,
so the dashboard shows names that don't match what actually got
registered.
Also adds a regression test that fails on the swapped order.
Co-authored-by: Mateo Wang <mateo-berri@users.noreply.github.com>
* Skip duplicate originals in _build_anthropic_tool_name_maps
If the same invalid tool name appeared twice in original_names (e.g.
['foo/bar', 'foo/bar']), the second occurrence overwrote the forward
map entry with a freshly-suffixed name (foo_bar_2), leaving foo_bar
orphaned in 'used' with no reverse mapping. _sanitize_tool_names_in_request
then rewrote both tool entries to foo_bar_2, and Anthropic 400'd on
duplicate tool names.
Skip the rewrite if forward already has the original mapped.
Co-authored-by: Mateo Wang <mateo-berri@users.noreply.github.com>
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
Co-authored-by: Mateo Wang <mateo-berri@users.noreply.github.com>
|
||
|---|---|---|
| .circleci | ||
| .devcontainer | ||
| .github | ||
| .semgrep/rules | ||
| ci_cd | ||
| cookbook | ||
| db_scripts | ||
| deploy | ||
| dist | ||
| docker | ||
| docs/my-website/docs | ||
| enterprise | ||
| litellm | ||
| litellm-js | ||
| litellm-proxy-extras | ||
| scripts | ||
| tests | ||
| ui/litellm-dashboard | ||
| .dockerignore | ||
| .env.example | ||
| .flake8 | ||
| .git-blame-ignore-revs | ||
| .gitattributes | ||
| .gitguardian.yaml | ||
| .gitignore | ||
| .npmrc | ||
| AGENTS.md | ||
| ARCHITECTURE.md | ||
| CLAUDE.md | ||
| codecov.yaml | ||
| CONTRIBUTING.md | ||
| cosign.pub | ||
| dev_config.yaml | ||
| docker-compose.hardened.yml | ||
| docker-compose.yml | ||
| Dockerfile | ||
| GEMINI.md | ||
| index.yaml | ||
| LICENSE | ||
| license_cache.json | ||
| Makefile | ||
| mcp_servers.json | ||
| model_prices_and_context_window.json | ||
| package-lock.json | ||
| package.json | ||
| policy_templates.json | ||
| prometheus.yml | ||
| provider_endpoints_support.json | ||
| proxy_server_config.yaml | ||
| pyproject.toml | ||
| pyrightconfig.json | ||
| README.md | ||
| render.yaml | ||
| ruff.toml | ||
| schema.prisma | ||
| security.md | ||
| taplo.toml | ||
| uv.lock | ||
🚅 LiteLLM
LiteLLM AI Gateway
Open Source AI Gateway for 100+ LLMs. Self-hosted. Enterprise-ready. Call any LLM in OpenAI format.
LiteLLM Proxy Server (AI Gateway) | Hosted Proxy | Enterprise Tier | Website
What is LiteLLM
LiteLLM is an open source AI Gateway that gives you a single, unified interface to call 100+ LLM providers — OpenAI, Anthropic, Gemini, Bedrock, Azure, and more — using the OpenAI format.
Use it as a Python SDK for direct library integration, or deploy the AI Gateway (Proxy Server) as a centralized service for your team or organization.
Jump to LiteLLM Proxy (LLM Gateway) Docs
Jump to Supported LLM Providers
Why LiteLLM
Managing LLM calls across providers gets complicated fast — different SDKs, auth patterns, request formats, and error types for every model. LiteLLM removes that friction:
- Unified API — one interface for 100+ LLMs, no provider-specific SDK juggling
- Drop-in OpenAI compatibility — swap providers without rewriting your code
- Production-ready gateway — virtual keys, spend tracking, guardrails, load balancing, and an admin dashboard out of the box
- 8ms P95 latency at 1k RPS (benchmarks)
OSS Adopters
Netflix |
Features
LLMs - Call 100+ LLMs (Python SDK + AI Gateway)
All Supported Endpoints - /chat/completions, /responses, /embeddings, /images, /audio, /batches, /rerank, /a2a, /messages and more.
Python SDK
uv add litellm
from litellm import completion
import os
os.environ["OPENAI_API_KEY"] = "your-openai-key"
os.environ["ANTHROPIC_API_KEY"] = "your-anthropic-key"
# OpenAI
response = completion(model="openai/gpt-4o", messages=[{"role": "user", "content": "Hello!"}])
# Anthropic
response = completion(model="anthropic/claude-sonnet-4-20250514", messages=[{"role": "user", "content": "Hello!"}])
AI Gateway (Proxy Server)
Getting Started - E2E Tutorial - Setup virtual keys, make your first request
uv tool install 'litellm[proxy]'
litellm --model gpt-4o
import openai
client = openai.OpenAI(api_key="anything", base_url="http://0.0.0.0:4000")
response = client.chat.completions.create(
model="gpt-4o",
messages=[{"role": "user", "content": "Hello!"}]
)
Agents - Invoke A2A Agents (Python SDK + AI Gateway)
Supported Providers - LangGraph, Vertex AI Agent Engine, Azure AI Foundry, Bedrock AgentCore, Pydantic AI
Python SDK - A2A Protocol
from litellm.a2a_protocol import A2AClient
from a2a.types import SendMessageRequest, MessageSendParams
from uuid import uuid4
client = A2AClient(base_url="http://localhost:10001")
request = SendMessageRequest(
id=str(uuid4()),
params=MessageSendParams(
message={
"role": "user",
"parts": [{"kind": "text", "text": "Hello!"}],
"messageId": uuid4().hex,
}
)
)
response = await client.send_message(request)
AI Gateway (Proxy Server)
Step 1. Add your Agent to the AI Gateway
Step 2. Call Agent via A2A SDK
from a2a.client import A2ACardResolver, A2AClient
from a2a.types import MessageSendParams, SendMessageRequest
from uuid import uuid4
import httpx
base_url = "http://localhost:4000/a2a/my-agent" # LiteLLM proxy + agent name
headers = {"Authorization": "Bearer sk-1234"} # LiteLLM Virtual Key
async with httpx.AsyncClient(headers=headers) as httpx_client:
resolver = A2ACardResolver(httpx_client=httpx_client, base_url=base_url)
agent_card = await resolver.get_agent_card()
client = A2AClient(httpx_client=httpx_client, agent_card=agent_card)
request = SendMessageRequest(
id=str(uuid4()),
params=MessageSendParams(
message={
"role": "user",
"parts": [{"kind": "text", "text": "Hello!"}],
"messageId": uuid4().hex,
}
)
)
response = await client.send_message(request)
MCP Tools - Connect MCP servers to any LLM (Python SDK + AI Gateway)
Python SDK - MCP Bridge
from mcp import ClientSession, StdioServerParameters
from mcp.client.stdio import stdio_client
from litellm import experimental_mcp_client
import litellm
server_params = StdioServerParameters(command="python", args=["mcp_server.py"])
async with stdio_client(server_params) as (read, write):
async with ClientSession(read, write) as session:
await session.initialize()
# Load MCP tools in OpenAI format
tools = await experimental_mcp_client.load_mcp_tools(session=session, format="openai")
# Use with any LiteLLM model
response = await litellm.acompletion(
model="gpt-4o",
messages=[{"role": "user", "content": "What's 3 + 5?"}],
tools=tools
)
AI Gateway - MCP Gateway
Step 1. Add your MCP Server to the AI Gateway
Step 2. Call MCP tools via /chat/completions
curl -X POST 'http://0.0.0.0:4000/v1/chat/completions' \
-H 'Authorization: Bearer sk-1234' \
-H 'Content-Type: application/json' \
-d '{
"model": "gpt-4o",
"messages": [{"role": "user", "content": "Summarize the latest open PR"}],
"tools": [{
"type": "mcp",
"server_url": "litellm_proxy/mcp/github",
"server_label": "github_mcp",
"require_approval": "never"
}]
}'
Use with Cursor IDE
{
"mcpServers": {
"LiteLLM": {
"url": "http://localhost:4000/mcp/",
"headers": {
"x-litellm-api-key": "Bearer sk-1234"
}
}
}
}
Supported Providers (Website Supported Models | Docs)
Get Started
You can use LiteLLM through either the Proxy Server or Python SDK. Both give you a unified interface to access multiple LLMs (100+ LLMs). Choose the option that best fits your needs:
| LiteLLM AI Gateway | LiteLLM Python SDK | |
|---|---|---|
| Use Case | Central service (LLM Gateway) to access multiple LLMs | Use LiteLLM directly in your Python code |
| Who Uses It? | Gen AI Enablement / ML Platform Teams | Developers building LLM projects |
| Key Features | Centralized API gateway with authentication and authorization, multi-tenant cost tracking and spend management per project/user, per-project customization (logging, guardrails, caching), virtual keys for secure access control, admin dashboard UI for monitoring and management | Direct Python library integration in your codebase, Router with retry/fallback logic across multiple deployments (e.g. Azure/OpenAI) - Router, application-level load balancing and cost tracking, exception handling with OpenAI-compatible errors, observability callbacks (Lunary, MLflow, Langfuse, etc.) |
Stable Release: Use docker images with the -stable tag. These have undergone 12 hour load tests, before being published. More information about the release cycle here
Support for more providers. Missing a provider or LLM Platform, raise a feature request.
Run in Developer Mode
Services
- Setup .env file in root
- Run dependant services
docker-compose up db prometheus
Backend
- (In root) create virtual environment
python -m venv .venv - Activate virtual environment
source .venv/bin/activate - Install dependencies
uv sync --all-extras --group proxy-dev uv run prisma generateprisma generate- Start proxy backend
python litellm/proxy/proxy_cli.py
Frontend
- Navigate to
ui/litellm-dashboard - Install dependencies
npm install - Run
npm run devto start the dashboard
Verify Docker Image Signatures
All LiteLLM Docker images published to GHCR are signed with cosign. Every release is signed with the same key introduced in commit 0112e53.
Verify using the pinned commit hash (recommended):
A commit hash is cryptographically immutable, so this is the strongest way to ensure you are using the original signing key:
cosign verify \
--key https://raw.githubusercontent.com/BerriAI/litellm/0112e53046018d726492c814b3644b7d376029d0/cosign.pub \
ghcr.io/berriai/litellm:<release-tag>
Verify using a release tag (convenience):
Tags are protected in this repository and resolve to the same key. This option is easier to read but relies on tag protection rules:
cosign verify \
--key https://raw.githubusercontent.com/BerriAI/litellm/<release-tag>/cosign.pub \
ghcr.io/berriai/litellm:<release-tag>
Replace <release-tag> with the version you are deploying (e.g. v1.83.0-stable).
Enterprise
For companies that need better security, user management and professional support
Get an Enterprise License Talk to founders
This covers:
- ✅ Features under the LiteLLM Commercial License:
- ✅ Feature Prioritization
- ✅ Custom Integrations
- ✅ Professional Support - Dedicated discord + slack
- ✅ Custom SLAs
- ✅ Secure access with Single Sign-On
Contributing
We welcome contributions to LiteLLM! Whether you're fixing bugs, adding features, or improving documentation, we appreciate your help.
Quick Start for Contributors
This requires uv to be installed.
git clone https://github.com/BerriAI/litellm.git
cd litellm
make install-dev # Install development dependencies
make format # Format your code
make lint # Run all linting checks
make test-unit # Run unit tests
make format-check # Check formatting only
For detailed contributing guidelines, see CONTRIBUTING.md.
📖 Contributing to documentation? The LiteLLM docs have moved to a separate repository: BerriAI/litellm-docs. Please open doc PRs there. Docs are served at docs.litellm.ai.
Code Quality / Linting
LiteLLM follows the Google Python Style Guide.
Our automated checks include:
- Black for code formatting
- Ruff for linting and code quality
- MyPy for type checking
- Circular import detection
- Import safety checks
All these checks must pass before your PR can be merged.
Support / talk with founders
- Schedule Demo 👋
- Community Discord 💭
- Community Slack 💭
- Our emails ✉️ ishaan@berri.ai / krrish@berri.ai