TRACTOR CRISP

Running in Docker

Building the Docker image

docker build . -t tractor-crisp

Configuring CRISP

First, copy the example crisp.toml config file into your project:

cp crisp.toml.example /path/to/my-project/crisp.toml

Replace /path/to/my-project with the path to the C project you want to translate. Afterwards, you may want to edit the new config file to customize it for your project.

Running CRISP

Run the Docker container:

docker run --rm -it -v /path/to/my-project:/root/project tractor-crisp

Then, within the container, run these commands:

cd /root/project

# Set up environment variables for accessing OpenAI models
export CRISP_API_BASE=https://api.openai.com/v1
export CRISP_API_KEY=sk-your-api-key-here
export CRISP_API_MODEL=gpt-5-2025-08-07

# As an alternative, you can direct CRISP to connect to llama.cpp or another
# OpenAI-compatible provider running on the host machine:
#export CRISP_API_BASE=http://172.17.0.1:8080/v1

# Import the original files into CRISP and tag them as `c_code`.  This command
# collects all of the `*.c`, `*.h`, and `CMakeLists.txt` files under the
# current directory; if more files are needed to build your C project, edit the
# command accordingly.
find . -name \*.c -o -name \*.h -o -name CMakeLists.txt \
    | xargs crisp commit -t c_code

# Run the CRISP transpiler loop
crisp main

# Export translated Rust from CRISP
crisp checkout
ls rust/

Running outside Docker

CRISP can also run directly on the host machine, using Docker to sandbox building and testing of the project (to protect against erroneous LLM outputs).

Setting up the Python virtual environment

CRISP is built and run using the uv tool

# Install uv, if needed:
curl -LsSf https://astral.sh/uv/install.sh | sh

uv sync

Building the sandbox container

docker build . -f Dockerfile.work -t tractor-crisp-user

Configuring CRISP

Set up crisp.toml as above.

Running CRISP

Set up a crisp alias in your shell:

export CRISP_DIR=/path/to/tractor-crisp
alias crisp='uv run --project $CRISP_DIR crisp'

Replace /path/to/tractor-crisp with the path to your tractor-crisp checkout.

Set up environment variables (CRISP_API_BASE etc.) as above.

Follow the same sequence of crisp commit + crisp main + crisp checkout as above.

Features

The following features have been implemented in the CRISP transpiler loop:

• Automatic translation of C to unsafe Rust using either c2rust-transpile or Hayroll. CRISP tries Hayroll first and falls back to ordinary c2rust-transpile only if it fails.
• LLM-based safety refactoring. CRISP uses an LLM to convert unsafe Rust to safe Rust. CRISP checks that the LLM-generated code builds and passes the tests before accepting it.
• LLM-based build and test repair. When code fails to build or doesn't pass tests, CRISP invokes an LLM to attempt to fix the problem. Output is built and tested again before accepting it.
• Automatic detection of unsafe code. The CRISP transpiler loop stops once there is no unsafe code left to make safe.
• FFI function splitting. To preserve ABI compatibility when translating libraries, some function signatures must remain unsafe. To minimize the amount of unsafe code, CRISP splits each such function into a small unsafe wrapper and a separate implementation function that can then be made safe.