ruff/crates/ty/docs/environment.md

Environment variables

ty defines and respects the following environment variables:

TY_LOG

If set, ty will use this value as the log level for its --verbose output. Accepts any filter compatible with the tracing_subscriber crate.

For example:

• TY_LOG=uv=debug is the equivalent of -vv to the command line
• TY_LOG=trace will enable all trace-level logging.

See the tracing documentation for more.

TY_LOG_PROFILE

If set to "1" or "true", ty will enable flamegraph profiling. This creates a tracing.folded file that can be used to generate flame graphs for performance analysis.

TY_MAX_PARALLELISM

Specifies an upper limit for the number of tasks ty is allowed to run in parallel.

For example, how many files should be checked in parallel. This isn't the same as a thread limit. ty may spawn additional threads when necessary, e.g. to watch for file system changes or a dedicated UI thread.

Externally-defined variables

ty also reads the following externally defined environment variables:

CONDA_DEFAULT_ENV

Used to determine the name of the active Conda environment.

CONDA_PREFIX

Used to detect the path of an active Conda environment. If both VIRTUAL_ENV and CONDA_PREFIX are present, VIRTUAL_ENV will be preferred.

PYTHONPATH

Adds additional directories to ty's search paths. The format is the same as the shell’s PATH: one or more directory pathnames separated by os appropriate pathsep (e.g. colons on Unix or semicolons on Windows).

RAYON_NUM_THREADS

Specifies an upper limit for the number of threads ty uses when performing work in parallel. Equivalent to TY_MAX_PARALLELISM.

This is a standard Rayon environment variable.

VIRTUAL_ENV

Used to detect an activated virtual environment.

XDG_CONFIG_HOME

Path to user-level configuration directory on Unix systems.

_CONDA_ROOT

Used to determine the root install path of Conda.