llmshim 0.2.3

Multi-provider LLM gateway — one interface, every provider

llmshim

One interface, every LLM provider. The proxy server starts automatically — no setup needed.

Install

pip install llmshim

Configure

import llmshim

# Set API keys (writes to ~/.llmshim/config.toml — only needed once)
llmshim.configure(
    anthropic="sk-ant-...",
    openai="sk-...",
    gemini="AIza...",
    xai="xai-...",
)

Or from the CLI: llmshim configure

Chat

import llmshim

resp = llmshim.chat("claude-sonnet-4-6", "What is Rust?")
print(resp["message"]["content"])

With options (all map to the API's provider-agnostic config):

resp = llmshim.chat(
    "openai/gpt-5.5",
    "Explain quicksort",
    max_tokens=500,
    temperature=0.7,
    top_p=0.9,
    top_k=40,
    stop=["\n\n"],
    reasoning_effort="high",
)

With message history:

resp = llmshim.chat("claude-sonnet-4-6", [
    {"role": "system", "content": "You are a pirate."},
    {"role": "user", "content": "Hello!"},
], max_tokens=500)

Streaming

for event in llmshim.stream("claude-sonnet-4-6", "Write a poem"):
    if event["type"] == "content":
        print(event["text"], end="", flush=True)
    elif event["type"] == "reasoning":
        pass  # thinking tokens
    elif event["type"] == "usage":
        print(f"\n[↑{event['input_tokens']} ↓{event['output_tokens']}]")

Multi-Model Conversations

Switch models mid-conversation. History carries over.

messages = [{"role": "user", "content": "What is a closure?"}]

r1 = llmshim.chat("claude-sonnet-4-6", messages, max_tokens=500)
print(f"Claude: {r1['message']['content']}")

messages.append({"role": "assistant", "content": r1["message"]["content"]})
messages.append({"role": "user", "content": "Now explain differently."})

r2 = llmshim.chat("gpt-5.5", messages, max_tokens=500)
print(f"GPT: {r2['message']['content']}")

Reasoning / Thinking

resp = llmshim.chat(
    "claude-sonnet-4-6",
    "Solve: x^2 - 5x + 6 = 0",
    max_tokens=4000,
    reasoning_effort="high",
)
print(resp["reasoning"])        # thinking content
print(resp["message"]["content"])  # answer

Tool Use / Function Calling

tools = [{
    "type": "function",
    "function": {
        "name": "get_weather",
        "description": "Get current weather",
        "parameters": {
            "type": "object",
            "properties": {"city": {"type": "string"}},
            "required": ["city"],
        },
    },
}]

resp = llmshim.chat("claude-sonnet-4-6", "Weather in Tokyo?", max_tokens=500, tools=tools)
for tc in resp["message"].get("tool_calls", []):
    print(f"{tc['function']['name']}({tc['function']['arguments']})")

Tools are accepted in OpenAI Chat Completions format and auto-translated to each provider's native format.

Fallback Chains

resp = llmshim.chat(
    "anthropic/claude-sonnet-4-6",
    "Hello",
    max_tokens=100,
    fallback=["openai/gpt-5.5", "gemini/gemini-3-flash-preview"],
)

Error Handling

Non-streaming errors (bad model, unknown provider, provider failures) raise LlmShimError, which carries the API's structured error fields:

try:
    llmshim.chat("unknown/model", "hi")
except llmshim.LlmShimError as e:
    print(e.status_code)  # 400
    print(e.code)         # "bad_request"
    print(e.message)      # human-readable message

Streaming errors that occur mid-stream instead arrive as an error event (event["type"] == "error"); an HTTP error before the stream starts still raises LlmShimError.

Types

Spec-faithful TypedDict definitions are available in llmshim.types (and the common ones are re-exported at the top level) for static type-checking:

from llmshim.types import ChatResponse, StreamEvent, Message, Config

resp: ChatResponse = llmshim.chat("claude-sonnet-4-6", "hi")

Available: ChatRequest, ChatResponse, Config, Message, ToolCall, Usage, ResponseMessage, ModelEntry, ModelsResponse, HealthResponse, ErrorResponse, and the StreamEvent union (ContentEvent, ReasoningEvent, ToolCallEvent, UsageEvent, DoneEvent, ErrorEvent).

Other

llmshim.models()   # list available models
llmshim.health()   # {"status": "ok", "providers": [...]}

How It Works

On first call, the package:

1. Finds the llmshim binary (bundled, on PATH, or in repo)
2. Starts the proxy on a random localhost port
3. Routes your request through it
4. Server stops automatically when Python exits

No Docker, no background services, no manual server management.

Development

The unit tests under tests/ are fully mocked — they run a local HTTP server returning canned JSON and SSE, so they need no API keys and make no real provider calls:

pip install httpx pytest
pytest tests/

test_e2e.py is a separate LIVE suite that spawns the real binary and makes billed provider calls; run it only when you deliberately want to hit real APIs.

Supported Models

Provider	Models
OpenAI	gpt-5.5, gpt-5.5-pro, gpt-5.4, gpt-5.4-pro, gpt-5.4-mini, gpt-5.4-nano
Anthropic	claude-opus-5, claude-opus-4-8, claude-sonnet-5, claude-opus-4-7, claude-opus-4-6, claude-sonnet-4-6, claude-haiku-4-5-20251001
Gemini	gemini-3.5-flash, gemini-3.1-pro-preview, gemini-3-flash-preview
xAI	grok-4.5, grok-4.3, grok-4.20-multi-agent-beta-0309, grok-4.20-beta-0309-reasoning, grok-4.20-beta-0309-non-reasoning

Call llmshim.models() for the live list filtered to your configured providers.