litellm/CLAUDE.md

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Development Commands

Installation

• make install-dev - Install core development dependencies
• make install-proxy-dev - Install proxy development dependencies with full feature set
• make install-test-deps - Install all test dependencies

Testing

• make test - Run all tests
• make test-unit - Run unit tests (tests/test_litellm) with 4 parallel workers
• make test-integration - Run integration tests (excludes unit tests)
• pytest tests/ - Direct pytest execution

Code Quality

• make lint - Run all linting (Ruff, MyPy, Black, circular imports, import safety)
• make format - Apply Black code formatting
• make lint-ruff - Run Ruff linting only
• make lint-mypy - Run MyPy type checking only

Single Test Files

• poetry run pytest tests/path/to/test_file.py -v - Run specific test file
• poetry run pytest tests/path/to/test_file.py::test_function -v - Run specific test

Running Scripts

• poetry run python script.py - Run Python scripts (use for non-test files)

GitHub Issue & PR Templates

When contributing to the project, use the appropriate templates:

Bug Reports (.github/ISSUE_TEMPLATE/bug_report.yml):

• Describe what happened vs. what you expected
• Include relevant log output
• Specify your LiteLLM version

Feature Requests (.github/ISSUE_TEMPLATE/feature_request.yml):

• Describe the feature clearly
• Explain the motivation and use case

Pull Requests (.github/pull_request_template.md):

• Add at least 1 test in tests/litellm/
• Ensure make test-unit passes

Architecture Overview

LiteLLM is a unified interface for 100+ LLM providers with two main components:

Core Library (litellm/)

• Main entry point: litellm/main.py - Contains core completion() function
• Provider implementations: litellm/llms/ - Each provider has its own subdirectory
• Router system: litellm/router.py + litellm/router_utils/ - Load balancing and fallback logic
• Type definitions: litellm/types/ - Pydantic models and type hints
• Integrations: litellm/integrations/ - Third-party observability, caching, logging
• Caching: litellm/caching/ - Multiple cache backends (Redis, in-memory, S3, etc.)

Proxy Server (litellm/proxy/)

• Main server: proxy_server.py - FastAPI application
• Authentication: auth/ - API key management, JWT, OAuth2
• Database: db/ - Prisma ORM with PostgreSQL/SQLite support
• Management endpoints: management_endpoints/ - Admin APIs for keys, teams, models
• Pass-through endpoints: pass_through_endpoints/ - Provider-specific API forwarding
• Guardrails: guardrails/ - Safety and content filtering hooks
• UI Dashboard: Served from _experimental/out/ (Next.js build)

Key Patterns

Provider Implementation

• Providers inherit from base classes in litellm/llms/base.py
• Each provider has transformation functions for input/output formatting
• Support both sync and async operations
• Handle streaming responses and function calling

Error Handling

• Provider-specific exceptions mapped to OpenAI-compatible errors
• Fallback logic handled by Router system
• Comprehensive logging through litellm/_logging.py

Configuration

• YAML config files for proxy server (see proxy/example_config_yaml/)
• Environment variables for API keys and settings
• Database schema managed via Prisma (proxy/schema.prisma)

Development Notes

Code Style

• Uses Black formatter, Ruff linter, MyPy type checker
• Pydantic v2 for data validation
• Async/await patterns throughout
• Type hints required for all public APIs
• Avoid imports within methods — place all imports at the top of the file (module-level). Inline imports inside functions/methods make dependencies harder to trace and hurt readability. The only exception is avoiding circular imports where absolutely necessary.

Testing Strategy

• Unit tests in tests/test_litellm/
• Integration tests for each provider in tests/llm_translation/
• Proxy tests in tests/proxy_unit_tests/
• Load tests in tests/load_tests/
• Always add tests when adding new entity types or features — if the existing test file covers other entity types, add corresponding tests for the new one

UI / Backend Consistency

• When wiring a new UI entity type to an existing backend endpoint, verify the backend API contract (single value vs. array, required vs. optional params) and ensure the UI controls match — e.g., use a single-select dropdown when the backend accepts a single value, not a multi-select

Database Migrations

• Prisma handles schema migrations
• Migration files auto-generated with prisma migrate dev
• Always test migrations against both PostgreSQL and SQLite

Enterprise Features

• Enterprise-specific code in enterprise/ directory
• Optional features enabled via environment variables
• Separate licensing and authentication for enterprise features