stprobe

stprobe is ffprobe for .safetensors.

It is a small Rust CLI for answering:

"What is inside this safetensors file?"

Point it at a model file and it prints a stable plain-text summary without loading tensor payloads into memory.

It works with local files and http(s) URLs, including Hugging Face resolve links.

Why stprobe:

fast: header-only inspection, including huge remote files over HTTP range requests
small: prebuilt release archives are about 2 MB and the tool is a single binary
easy: one command, no Python environment, stable plain-text output

Because it only probes the safetensors header and metadata, it is fast even for very large remote files.

stprobe shows:

file path
file size
tensor count
metadata
per-tensor name, dtype, shape, parameter count, and byte size
total parameters
total tensor bytes
dtype breakdown

It is built for model inspection, debugging, issue reports, and quick shell use.

no Python environment
no notebook setup
no ad hoc parsing script
header-only inspection with the official safetensors crate
remote probing over HTTP range requests instead of downloading the full file
stable plain-text output that is easy to read, diff, grep, and paste

Install

Use a prebuilt binary from GitHub Releases if you just want to run stprobe without installing Rust:

Download the archive for Linux x86_64, macOS Intel, macOS Apple Silicon, or Windows x86_64 from: https://github.com/Xyc2016/stprobe/releases/latest
Extract it and run stprobe --version

Linux x86_64 example:

curl -L https://github.com/Xyc2016/stprobe/releases/latest/download/stprobe-x86_64-unknown-linux-gnu.tar.gz | tar -xz
./stprobe --version

Or install from crates.io:

cargo install stprobe

Quick Start

stprobe all-MiniLM-L6-v2.safetensors

Example:

$ stprobe all-MiniLM-L6-v2.safetensors
File: all-MiniLM-L6-v2.safetensors
Size: 90868376 bytes
Tensors: 104
Parameters: 22713728
Tensor-Bytes: 90856960

Metadata:
  format = pt

DType Breakdown:
  F32: 90852864 bytes
  I64: 4096 bytes

Tensors:
  embeddings.position_ids
    dtype: I64
    shape: [1, 512]
    numel: 512
    bytes: 4096

  embeddings.word_embeddings.weight
    dtype: F32
    shape: [30522, 384]
    numel: 11720448
    bytes: 46881792

Fast On Huge Remote Files

You can also probe a large Hugging Face model directly over HTTP without downloading the full .safetensors file first:

time stprobe https://huggingface.co/Comfy-Org/flux1-dev/resolve/main/flux1-dev-fp8.safetensors

Example:

$ time stprobe https://huggingface.co/Comfy-Org/flux1-dev/resolve/main/flux1-dev-fp8.safetensors
File: https://huggingface.co/Comfy-Org/flux1-dev/resolve/main/flux1-dev-fp8.safetensors
Size: 17246524772 bytes
Tensors: 1442
Parameters: 16871188965
Tensor-Bytes: 17246298324

Metadata:
  modelspec.architecture = Flux.1-dev
  modelspec.author = Black Forest Labs
  modelspec.date = 2024-08-01
  modelspec.description = A guidance distilled rectified flow model.
  modelspec.license = FLUX.1 [dev] Non-Commercial License
  modelspec.title = Flux.1-dev

DType Breakdown:
  F16: 247300608 bytes
  F32: 335278740 bytes
  F8_E4M3: 16663718976 bytes

Tensors:
  text_encoders.clip_l.logit_scale
    dtype: F32
    shape: []
    numel: 1
    bytes: 4

  ...

  text_encoders.t5xxl.transformer.shared.weight
    dtype: F8_E4M3
    shape: [32128, 4096]
    numel: 131596288
    bytes: 131596288

stprobe https://huggingface.co/Comfy-Org/flux1-dev/resolve/main/flux1-dev-fp8.safetensors  0.01s user 0.02s system 2% cpu 1.277 total

Example timing from one local machine using the optimized build. Exact results vary with network, filesystem cache, shell, and hardware.

Why Not A One-Off Script

You can inspect a safetensors file with a short Rust or Python script. stprobe is better when you want something you can keep using:

one command instead of re-editing one-off scripts
stable output for bug reports, CI logs, and terminal use
no Python packaging, no notebook, no local helper code
uses the official safetensors crate instead of custom header parsing
reads only the safetensors header and metadata when that is all you need

Build From Source

cargo install --path .

Or run it without installing: