* feat(lasso): extend LassoGuardrail to support tool calling (RND-5748)
* fix(lasso): PR review followups for tool-calling guardrail (RND-5748)
* fix(lasso): handle object-style tool_calls in _update_tool_calls_from_masked (RND-5748)
* fix(lasso): use model role for tool_use blocks (RND-5748)
* test(lasso): add round-trip tests for message transformation (RND-5748)
* fix(lasso): remove unused imports, handle Responses-API input masking, flatten multimodal content (RND-5748)
* fix(lasso): inspect Responses-API input field (RND-5748)
* fix(lasso): guard text-cursor remap against Lasso count mismatch (RND-5748)
* fix(lasso): flatten list content in tool_result.content (RND-5748)
* fix(lasso): remap multimodal list content during masking (RND-5748)
Bug: _map_masked_messages_back counted list-content messages in
original_text_count but the remap loop only handled isinstance(str).
The positional text_cursor never advanced for list messages, causing
all subsequent masked texts to be written onto the wrong messages.
Fix: added elif isinstance(content, list) branch that replaces the
list with the masked text string and advances the cursor — mirrors
the existing string-content branch. Also handles the assistant +
tool_calls combo for list-content messages.
Test: test_map_masked_messages_back_list_content verifies a user
message with [text + image_url] followed by an assistant message
gets correct masked content on both (cursor stays aligned).
* refactor(lasso): extract _get_field and _extract_tool_call_fields helpers (RND-5748)
The dict-vs-object access pattern (x.get('y') if isinstance(x, dict)
else getattr(x, 'y', None)) was duplicated 14 times across 5 methods.
_get_field(obj, field) — single-point dict/Pydantic field access.
_extract_tool_call_fields(call) — returns (call_id, name, parsed_input)
with JSON argument parsing, replacing ~30 duplicate lines in both
async_post_call_success_hook and _expand_messages_for_classification.
Also simplified _update_tool_calls_from_masked, _prepare_payload tool
mapping, and _apply_masking_to_model_response call_id extraction.
Net ~60 lines removed. No behavior change — all 32 tests pass.
* fix(lasso): add count guard to _apply_masking_to_model_response (RND-5748)
_apply_masking_to_model_response used a bare text_cursor without
verifying 1:1 correspondence between text-bearing choices and masked
text entries. If Lasso returned a different number of text messages
than choices with content, masked text would be applied to the wrong
choice or silently skip choices.
Added the same count-mismatch guard pattern already used in
_map_masked_messages_back: count original text-bearing choices,
compare to masked_text length, skip text remap on mismatch with a
warning log. Tool_call masking via id-based lookup is unaffected.
Tests:
- test_apply_masking_to_model_response_multiple_choices: verifies
correct per-choice masked text with 2 choices
- test_apply_masking_to_model_response_count_mismatch: verifies
content is left unchanged when counts disagree
* fix(lasso): close two guardrail-bypass paths flagged in review (RND-5748)
* tool-call args: when function.arguments is malformed JSON or parses
to a non-object, preserve the raw string as {"arguments": <raw>} so
Lasso still inspects it instead of receiving input=None. Covers both
pre-call and post-call extraction (shared helper). Also resolves the
CodeQL empty-except warning since the except body now assigns parsed=None.
* Responses-API input: when a request carries both "messages" and
"input", inspect both. Previously a benign messages array let the
guardrail skip data["input"] entirely. The masking write-back is
split via a count boundary so masked messages flow back to
data["messages"] and masked input flows back to data["input"]
without cross-contamination.
Tests: malformed/non-object args round-trip, dual-field classification,
dual-field masking write-back split.
* chore(lasso): black formatting + comment on expand skip branch (RND-5748)
* black: wrap two long expressions in lasso.py and reformat dict
literals in test_lasso.py to satisfy CI lint.
* add a short comment in _expand_messages_for_classification
explaining why empty string and None content are intentionally
skipped (None is the OpenAI shape for a pure tool-call turn).
* fix(lasso): satisfy mypy in _handle_masking, _update_tool_calls_from_masked, _apply_masking_to_model_response (RND-5748)
* Narrow `response.get("messages")` into a local before slicing so
mypy doesn't see `Optional[List[Dict[str, str]]]` as non-indexable.
* Rename the two write-side `func` bindings in
`_update_tool_calls_from_masked` to `func_dict` / `func_obj` so
mypy doesn't unify the dict and Any|None branches.
* Rename the inner loop variable in `_apply_masking_to_model_response`
from `msg` to `masked_msg` to avoid clashing with the
`msg = choice.message` rebinding below.
No behavior change; resolves the 7 mypy errors from the CI lint job.
🚅 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