Fill PDF

Fill AcroForm PDFs by mapping context keys to form fields and running pdftk with an FDF payload.

Workflow

1. Validate prerequisites.

• Confirm pdftk is installed before doing form operations.
• Treat this skill as AcroForm-focused; if the PDF has no fillable fields, report that and stop.

2. Inspect field names.

• Run:

pdftk <input.pdf> dump_data_fields_utf8

• Capture exact FieldName values and use them as target keys.

3. Build context map.

• Normalize provided context into a flat JSON object where each key is an exact field name.
• Convert values to strings when needed.
• Leave missing fields out unless the user asks for explicit blanks.

4. Fill the PDF with pdftk.

• Preferred helper:

scripts/fill_pdf.sh --input <input.pdf> --context <context.json> --output <output.pdf> [--flatten]

• The helper converts JSON context to FDF and calls:

pdftk <input.pdf> fill_form <tmp.fdf> output <output.pdf>

5. Verify result.

• Confirm output file exists and is non-empty.
• If the user asks for non-editable output, use --flatten.

Quick Commands

List field names:

scripts/fill_pdf.sh --list-fields --input <input.pdf>

Fill from context JSON:

scripts/fill_pdf.sh --input <input.pdf> --context <context.json> --output <output.pdf>

Fill and flatten:

scripts/fill_pdf.sh --input <input.pdf> --context <context.json> --output <output.pdf> --flatten

Notes

• Keep context keys aligned to exact PDF field names; guessing names causes silent misses.
• Prefer dump_data_fields_utf8 output over visual assumptions from labels.
• If a field does not populate, re-check case and punctuation in the key.

Resources

scripts/

• fill_pdf.sh: Lists form fields and fills PDFs from a JSON context file via pdftk.