mi-crow 1.0.0.post6

Python library for mechanistic interpretability research on Large Language Models. Designed for researchers, provides unified interface for SAE training, activation hooks, and concept manipulation.

Mi-Crow: Mechanistic Interpretability for Large Language Models

Mi-Crow is a Python library for mechanistic interpretability research on Large Language Models (LLMs). Designed for researchers, it provides a unified interface for analyzing and controlling model behavior through Sparse Autoencoders (SAEs), activation hooks, and concept manipulation.

Features

• Unified Model Interface - Work with any HuggingFace language model through a consistent API
• Sparse Autoencoder Training - Train SAEs to extract interpretable features from model activations
• Hook System - Intercept and manipulate model activations with minimal performance overhead
• Concept Discovery & Manipulation - Discover and control model behavior through learned concepts
• Hierarchical Data Persistence - Efficient storage and management of large-scale experiment data
• Research Focused - Comprehensive testing (85%+ coverage), extensive documentation, and designed for interpretability research workflows

Installation

Install from PyPI

pip install mi-crow

Install from Source

git clone https://github.com/AdamKaniasty/Mi-Crow.git
cd Mi-Crow
pip install -e .

Requirements

• Python 3.12+ (required for modern type hints and features)
• PyTorch - Tensor operations and neural networks
• Transformers - Model loading and tokenization
• Accelerate - Distributed and mixed-precision training
• Datasets - Dataset loading and processing
• overcomplete - SAE implementations

Quick Start

Basic Usage

from mi_crow.language_model import LanguageModel

# Initialize a language model
lm = LanguageModel(model_id="bielik")

# Run inference
outputs = lm.forwards(["Hello, world!"])

# Access activations and outputs
print(outputs.logits)

Training an SAE

from mi_crow.language_model import LanguageModel
from mi_crow.mechanistic.sae import SaeTrainer
from mi_crow.mechanistic.sae.modules import TopKSae

# Load model and collect activations
lm = LanguageModel(model_id="bielik")
activations = lm.save_activations(
    dataset=["Your text data here"],
    layers=["transformer_h_0_attn_c_attn"]
)

# Train SAE
trainer = SaeTrainer(
    model=lm,
    layer="transformer_h_0_attn_c_attn",
    sae_class=TopKSae,
    hyperparams={"epochs": 10, "batch_size": 256}
)
sae = trainer.train(activations)

Concept Manipulation

# Load concepts and manipulate model behavior
concepts = lm.load_concepts(sae_id="your_sae_id")
concepts.manipulate(neuron_idx=0, scale_factor=1.5)

# Run inference with concept manipulation
outputs = lm.forwards(
    ["Your prompt"],
    with_controllers=True,
    concept_config=concepts
)

Documentation

• Full Documentation: adamkaniasty.github.io/Inzynierka
• GitHub Repository: github.com/AdamKaniasty/Mi-Crow
• Example Notebooks: See examples/ directory for Jupyter notebook tutorials

Architecture

Mi-Crow follows a modular design with five core components:

1. language_model/ - Unified interface for language models

   • Model initialization from HuggingFace Hub or local files
   • Unified inference interface with mixed-precision support
   • Architecture-agnostic layer abstraction

2. hooks/ - Flexible hook system for activation interception

   • Detectors for observing activations
   • Controllers for modifying model behavior
   • Support for FORWARD and PRE_FORWARD hooks

3. mechanistic/ - SAE training and concept manipulation

   • Sparse Autoencoder training (TopK, L1 variants)
   • Concept dictionary management
   • Concept-based model steering

4. store/ - Hierarchical data persistence

   • Efficient tensor storage in safetensors format
   • Batch iteration for large datasets
   • Metadata management

5. datasets/ - Dataset loading and processing

   • HuggingFace dataset integration
   • Local file dataset support

Example Workflow

See the example notebooks in the examples/ directory:

1. 01_train_sae_model.ipynb - Train an SAE on model activations
2. 02_attach_sae_and_save_texts.ipynb - Collect top activating texts
3. 03_load_concepts.ipynb - Load and manipulate concepts

Development

Running Tests

The project uses pytest for testing. Tests are organized into unit tests and end-to-end tests.

Running All Tests

pytest

Running Specific Test Suites

Run only unit tests:

pytest --unit -q

Run only end-to-end tests:

pytest --e2e -q

You can also use pytest markers:

pytest -m unit -q
pytest -m e2e -q

Or specify the test directory directly:

pytest tests/unit -q
pytest tests/e2e -q

Test Coverage

The test suite is configured to require at least 85% code coverage. Coverage reports are generated in both terminal and XML formats.

The project maintains 85%+ code coverage requirement.

Code Quality

• Linting: Ruff for code formatting and linting
• Pre-commit Hooks: Automated quality checks
• Type Hints: Extensive use of Python type annotations
• CI/CD: GitHub Actions for automated testing and deployment

Citation

If you use Mi-Crow in your research, please cite:

@thesis{kaniasty2025microw,
  title={Mechanistic Interpretability for Large Language Models: A Production-Ready Framework},
  author={Kaniasty, Adam and Kowalski, Hubert},
  year={2025},
  school={Warsaw University of Technology},
  note={Engineering Thesis}
}

License

See the main repository for license information: Mi-Crow License

Contact

• Maintainers: Adam Kaniasty, Hubert Kowalski
• Email: [e-mail]
• GitHub: @AdamKaniasty

Acknowledgments

This work was developed in collaboration with the Bielik team and represents a contribution to the open-source mechanistic interpretability community.

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Backend (FastAPI) quickstart

Install server-only dependencies (kept out of the core library) with uv:

uv sync --group server

Run the API:

uv run --group server uvicorn server.main:app --reload

Smoke-test the server endpoints:

uv run --group server pytest tests/server/test_api.py --cov=server --cov-fail-under=0

SAE API usage

• Configure artifact location (optional): export SERVER_ARTIFACT_BASE_PATH=/path/to/mi_crow_artifacts (defaults to ~/.cache/mi_crow_server)
• Load a model: curl -X POST http://localhost:8000/models/load -H "Content-Type: application/json" -d '{"model_id":"bielik"}'
• Save activations from dataset (stored in LocalStore under activations/<model>/<run_id>):
  • HF dataset: {"dataset":{"type":"hf","name":"ag_news","split":"train","text_field":"text"}}
  • Local files: {"dataset":{"type":"local","paths":["/path/to/file.txt"]}}
  • Example: curl -X POST http://localhost:8000/sae/activations/save -H "Content-Type: application/json" -d '{"model_id":"bielik","layers":["dummy_root"],"dataset":{"type":"local","paths":["/tmp/data.txt"]},"sample_limit":100,"batch_size":4,"shard_size":64}' → returns a manifest path, run_id, token counts, and batch metadata.
• List activation runs: curl "http://localhost:8000/sae/activations?model_id=bielik"
• Start SAE training (async job, uses SaeTrainer): curl -X POST http://localhost:8000/sae/train -H "Content-Type: application/json" -d '{"model_id":"bielik","activations_path":"/path/to/manifest.json","layer":"<layer_name>","sae_class":"TopKSae","hyperparams":{"epochs":1,"batch_size":256}}' → returns job_id
• Check job status: curl http://localhost:8000/sae/train/status/<job_id> (returns sae_id, sae_path, metadata_path, progress, and logs)
• Cancel a job (best-effort): curl -X POST http://localhost:8000/sae/train/cancel/<job_id>
• Load an SAE: curl -X POST http://localhost:8000/sae/load -H "Content-Type: application/json" -d '{"model_id":"bielik","sae_path":"/path/to/sae.json"}'
• List SAEs: curl "http://localhost:8000/sae/saes?model_id=bielik"
• Run SAE inference (optionally save top texts and apply concept config): curl -X POST http://localhost:8000/sae/infer -H "Content-Type: application/json" -d '{"model_id":"bielik","sae_id":"<sae_id>","save_top_texts":true,"top_k_neurons":5,"concept_config_path":"/path/to/concepts.json","inputs":[{"prompt":"hi"}]}' → returns outputs, top neuron summary, sae metadata, and saved top-texts path when requested.
• Per-token latents: add "return_token_latents": true (default off) to include top-k neuron activations per token.
• List concepts: curl "http://localhost:8000/sae/concepts?model_id=bielik&sae_id=<sae_id>"
• Load concepts from a file (validated against SAE latents): curl -X POST http://localhost:8000/sae/concepts/load -H "Content-Type: application/json" -d '{"model_id":"bielik","sae_id":"<sae_id>","source_path":"/path/to/concepts.json"}'
• Manipulate concepts (saves a config file for inference-time scaling): curl -X POST http://localhost:8000/sae/concepts/manipulate -H "Content-Type: application/json" -d '{"model_id":"bielik","sae_id":"<sae_id>","edits":{"0":1.2}}'
• List concept configs: curl "http://localhost:8000/sae/concepts/configs?model_id=bielik&sae_id=<sae_id>"
• Preview concept config (validate without saving): curl -X POST http://localhost:8000/sae/concepts/preview -H "Content-Type: application/json" -d '{"model_id":"bielik","sae_id":"<sae_id>","edits":{"0":1.2}}'
• Delete activation run or SAE (requires API key if set): curl -X DELETE "http://localhost:8000/sae/activations/<run_id>?model_id=bielik" -H "X-API-Key: <key>" and curl -X DELETE "http://localhost:8000/sae/saes/<sae_id>?model_id=bielik" -H "X-API-Key: <key>"
• Health/metrics summary: curl http://localhost:8000/health/metrics (in-memory job counts; no persistence, no auth)

Notes:

• Job manager is in-memory/lightweight: jobs disappear on process restart; idempotency is best-effort via payload key.
• Training/inference currently run in-process threads; add your own resource guards when running heavy models.
• Optional API key protection: set SERVER_API_KEY=<value> to require X-API-Key on protected endpoints (delete).