callhome what local AI tools send out by default, and the switch for each

the phone-home register

huggingface_hub

What huggingface_hub sends out of your computer by default, when, to whom, and the switch that stops it, version by version, with how we know.

The answer

By its source at v1.27.0 and its environment-variables page, not run: on each request to the Hugging Face Hub, huggingface_hub names the calling library and its version, its own version, the Python version, the PyTorch version and any AI agent it detects in the request's user agent, and HF_HUB_DISABLE_TELEMETRY=1 (or DO_NOT_TRACK=1) leaves the last two out of a request the library makes anyway; the hf command also asks pypi.org (a Homebrew install asks Homebrew's registry instead) for a newer release at start, at most once every 24 hours, and HF_HUB_DISABLE_UPDATE_CHECK=1 stops that.

Builds and versions

not installed: source read at tag v1.27.0On by default?yes · read in code and in its own documents; yes · read in codeMeasured here?no · read in codeDate checked (UTC)2026-10-10
Version
1.27.0 · the source at tag v1.27.0
Where the evidence came from
not run: the source applies to every platform
On by default?
yes · read in code and in its own documents: when you run the hf command; yes · read in code: fields in the user agent of every Hub request
Measured here?
no · read in code
Date checked (UTC)
2026-10-10
Why we say so
src/huggingface_hub/cli/_cli_utils.py read at tag v1.27.0 (the check, its once-a-day marker and its request), and its environment-variables page; src/huggingface_hub/utils/_headers.py and constants.py, and its environment-variables page, read at tag v1.27.0

Each call out

cli update check · 1.27.0

Version · build
1.27.0 · the source at tag v1.27.0 · not run: the source applies to every platform · not installed: source read at tag v1.27.0
Sends by default
yes · read in code and in its own documents: when you run the hf command
Kind
checks
Trigger
as a side effect of a local request
When
Read in code at v1.27.0: at the hf command's start, at most once every 24 hours (a marker file records the last check); a Homebrew install asks Homebrew's registry instead of PyPI; not run.
Where
update service · pypi.org
What it sends
a request to PyPI for the newest release (request)
The vendor's stated purpose
“By default, the `hf` CLI checks PyPI for a newer release at startup (at most once every 24 hours) and prints a one-line yellow warning to stderr when one is available, suggesting `hf update`.” — environment_variables.md at v1.27.0, read 2026-10-10
Grade and method
read · src/huggingface_hub/cli/_cli_utils.py read at tag v1.27.0 (the check, its once-a-day marker and its request), and its environment-variables page · read 2026-10-10
Receipts
its environment-variables page, HF_HUB_DISABLE_UPDATE_CHECK · the check, its 24-hour marker, and its request to PyPI

user agent fields · 1.27.0

Version · build
1.27.0 · the source at tag v1.27.0 · not run: the source applies to every platform · not installed: source read at tag v1.27.0
Sends by default
yes · read in code: fields in the user agent of every Hub request
Kind
reports
Trigger
as a side effect of a local request
When
Read in code at v1.27.0: on every Hub request, inside the request's user agent; not run.
Where
model hub · huggingface.co
What it sends
the calling library's name and version, huggingface_hub's version, the Python version (software); the PyTorch version, and the name of an AI agent it detects (both left out when telemetry is off) (software)
The vendor's stated purpose
“By default, some data is collected by HF libraries (`transformers`, `datasets`, `gradio`,..) to monitor usage, debug issues and help prioritize features.” — environment_variables.md at v1.27.0, read 2026-10-10
Also know
HF_HUB_OFFLINE=1 stops every Hub call: no download, no update check of cached files. — github.com · environment_variables.md, read 2026-10-10
Grade and method
read · src/huggingface_hub/utils/_headers.py and constants.py, and its environment-variables page, read at tag v1.27.0 · read 2026-10-10
Receipts
the user agent and the fields telemetry adds · the switch and DO_NOT_TRACK · its environment-variables page, HF_HUB_DISABLE_TELEMETRY

The switch

HF_HUB_DISABLE_UPDATE_CHECK=1

Accepted values
1
What it is
environment variable
Where it must be set
in the environment of the program, before it starts (see Turn them off) · turn them off
Also turns off
the hint about the hf-cli skill
What turning it off costs
you are no longer told that a newer hf release exists
Proof
documented; not tested by us
For the call
cli update check · 1.27.0

HF_HUB_DISABLE_TELEMETRY=1

Accepted values
1
What it is
environment variable
Where it must be set
in the environment of the program, before it starts (see Turn them off) · turn them off
Other spellings
DO_NOT_TRACK=1
Also turns off
the telemetry other libraries send through its send_telemetry function
What turning it off costs
none known: its documents name no other effect
Proof
documented; not tested by us. The switch changes the content of a request the library makes anyway, so only a run that reads content could decide it.
For the call
user agent fields · 1.27.0

Listens beyond the machine, and other cloud features

Listens beyond the machine by default

  • n/a · a command-line tool (1.27.0 the source at tag v1.27.0)
  • n/a · a library (1.27.0 the source at tag v1.27.0)

Other cloud features

None found.

What it leaves on disk

  • .cache/huggingface/.check_for_update_done (or under $HF_HOME) · an empty marker file whose age dates the last check

Has it already run on your machine?

Brings in, and installed for you by

None on the register.

Credit

  • The switch is documented, and its code reads DO_NOT_TRACK as the same switch for the telemetry sent through its public send_telemetry function; not tested by us. — github.com · constants.py, read 2026-10-10

Vendor documents it? · public discussion

Vendor documents it?

Public discussion

History

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Not yet checked

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