Deterministic regression enforcement for LLM systems.
Project description
Phylax
Deterministic regression enforcement for LLM systems.
The Problem
LLM outputs change unexpectedly. Same prompt, different model version → different behavior. Without Phylax, you discover this in production.
Installation
pip install phylax
For all LLM providers (OpenAI, Gemini, Groq, Mistral, HuggingFace, Ollama):
pip install phylax[all]
Individual providers:
pip install phylax[openai] # OpenAI
pip install phylax[google] # Gemini (google-genai SDK)
pip install phylax[groq] # Groq LPU
pip install phylax[mistral] # Mistral AI
pip install phylax[huggingface] # HuggingFace Inference API
pip install phylax[ollama] # Ollama (local models)
Quick Start
from phylax import trace, expect, execution, GeminiAdapter
@trace(provider="gemini")
@expect(must_include=["hello"], max_latency_ms=5000)
def greet(name: str):
"""Traced Gemini call with expectations."""
adapter = GeminiAdapter()
response, _ = adapter.generate(
prompt=f"Say hello to {name}",
model="gemini-2.5-flash",
)
return response
# Single call
result = greet("World")
print(result.text)
# Track multi-step agent flows
with execution() as exec_id:
step1 = greet("Alice")
step2 = greet("Bob")
# Start the UI server
phylax server
# Open http://127.0.0.1:8000/ui
# Mark a known-good response as baseline
phylax bless <trace_id>
# In CI: fail if output regresses
phylax check # exits 1 on failure
That's it. Your CI now blocks LLM regressions.
Supported Providers
| Provider | Adapter | Env Variable |
|---|---|---|
| OpenAI | OpenAIAdapter |
OPENAI_API_KEY |
| Gemini | GeminiAdapter |
GOOGLE_API_KEY |
| Groq | GroqAdapter |
GROQ_API_KEY |
| Mistral | MistralAdapter |
MISTRAL_API_KEY |
| HuggingFace | HuggingFaceAdapter |
HF_TOKEN |
| Ollama | OllamaAdapter |
OLLAMA_HOST |
from phylax import OpenAIAdapter, GroqAdapter, MistralAdapter
# All adapters share the same interface
adapter = GroqAdapter()
response, trace = adapter.generate(prompt="Hello!", model="llama3-70b-8192")
What Phylax is NOT
- ❌ Not monitoring — no metrics, no dashboards
- ❌ Not observability — no traces-to-cloud, no analytics
- ❌ Not AI judgment — rules are deterministic, not LLM-based
- ❌ Not cloud-dependent — runs entirely local
- ❌ Not prompt engineering — tests outputs, not prompts
Phylax is a test framework. It tells you when LLM behavior changes.
CI Integration
# .github/workflows/phylax.yml
- run: phylax check
env:
GOOGLE_API_KEY: ${{ secrets.GOOGLE_API_KEY }}
Exit codes:
0— All golden traces pass1— Regression detected
Commands
| Command | What it does |
|---|---|
phylax init |
Initialize config |
phylax server |
Start API server + UI |
phylax list |
List traces |
phylax list --failed |
Show only failed traces |
phylax show <id> |
Show trace details |
phylax replay <id> |
Re-run a trace |
phylax bless <id> |
Mark as golden baseline |
phylax check |
CI regression check |
Features
| Feature | Description |
|---|---|
| Trace Capture | Record every LLM call automatically |
| Expectations | Validate with @expect rules |
| Execution Context | Group traces by execution() context |
| Golden Traces | Baseline comparisons with hash verification |
| Golden Reference UI | ⭐ Bless/unbless traces from web interface |
| Trace ID Search | 🔍 Search traces by ID in sidebar |
| CI Integration | phylax check exits 1 on regression |
| Web UI | View traces at http://127.0.0.1:8000/ui |
| Multi-Provider | OpenAI, Gemini, Groq, Mistral, HuggingFace, Ollama |
Demos
See the demos/ directory for runnable examples:
python demos/01_basic_trace.py # Basic tracing
python demos/02_expectations.py # All @expect rules
python demos/03_execution_context.py # Trace grouping
python demos/04_graph_nodes.py # Graph API
python demos/05_golden_workflow.py # CI workflow
python demos/06_raw_evidence.py # Evidence API
python demos/07_error_contracts.py # Error codes
Documentation
License
MIT License
Project details
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