DeepSeek Harness .zstd session files, frame by frame
Zstd Frame Inspector is a browser page that reads the frame structure of a `.zstd` DSH session file without decompressing it.
DSH sessions are append-only multi-frame zstd. When one grows to 20 MB, the useful question is not “how big” but “how many frames, and where do they end”.
Frame boundaries
| # | Type | Offset | Compressed size | Blocks |
|---|---|---|---|---|
| No frames parsed yet. | ||||
Frame offsets are exact byte positions in the file. In DSH sessions each frame typically corresponds to an append batch, so frame count is a good proxy for how many writes the file has accumulated — and the last frame size tells you how much the next sync would send.
Common questions
Does it decompress the file?
No. It walks frame and block headers. Nothing is inflated, so even a 1 GB file stays cheap.
Why not show the uncompressed size?
Streaming writers often omit the content-size field, so the honest answer is usually unavailable. Frame boundaries are exact; invented numbers are not.
Is my file uploaded?
No. There is no backend. The file is read with the File API inside the page.