The official MCS-150/150B/150C PDFs ship with 8 (150/150B) or 4 (150C)
FMCSA instruction/example pages before the actual fillable form. We were
generating + faxing/submitting all of them. Trimmed the source templates
down to the FORM pages only:
MCS-150 11 -> 3 pages (289 fields preserved)
MCS-150B 12 -> 4 pages (349 fields preserved)
MCS-150C 6 -> 2 pages (33 fields preserved)
The filler iterates writer.pages (no absolute index) and signature
anchors are derived dynamically via enumerate(reader.pages), so no
page-specific markup needed fixing. Removed one-off diag script.
- fill_mcs150 now uses auto_regenerate=True so pypdf writes appearance
streams for every text field. Preview/Chrome ignore /NeedAppearances and
were showing blank widgets over the values; generated /AP streams make
the text render in all viewers.
- New verify_mcs150.py reads each widget's /AP /N appearance stream (the
literal drawn glyphs) to confirm expected values actually render, since
the container has no OCR/raster tooling. Exits non-zero on any miss.
Customer saw the MCS-150 looking blank / 'data covered by the form fields': the
values were correctly written to the AcroForm /V, but pypdf left the template's
empty /AP appearance streams in place and NeedAppearances was false, so viewers
rendered the blank widget over the value. Setting AcroForm /NeedAppearances=true
makes viewers regenerate appearances from the values. (The missing signature was
a downstream effect of the separate fobj_put MinIO-upload bug, now fixed -- with
no PDF in MinIO the anchor extraction + signature stamping both failed.)
Uses pypdf to fill the official MCS-150/150B/150C fillable PDFs.
Maps intake data to 289 form fields (text + checkboxes).
Supports form type detection (standard vs hazmat vs intermodal).
Produces ready-to-fax PDF from intake data.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
