PDF Verification Check 112b09

PDF Verification Check

After generating PDF files, always programmatically verify their structure and integrity before declaring task completion. This catches formatting errors, incorrect page counts, and corrupted files early.

When to Use

Use this skill whenever your task involves:

• Generating PDF documents
• Creating PDFs with specific page count requirements
• Producing multi-part PDF outputs (e.g., listings + maps)

Verification Steps

1. Install PyPDF2 (if not available)

pip install PyPDF2

2. Verify PDF Page Count and Integrity

Create a verification script or run inline Python:

from PyPDF2 import PdfReader
import os

def verify_pdf(pdf_path, expected_pages=None):
    """Verify PDF file exists, is readable, and has expected page count."""
    try:
        # Check file exists
        if not os.path.exists(pdf_path):
            return False, f"File not found: {pdf_path}"
        
        # Check file size (non-empty)
        file_size = os.path.getsize(pdf_path)
        if file_size == 0:
            return False, f"Empty file: {pdf_path}"
        
        # Open and verify PDF structure
        reader = PdfReader(pdf_path)
        actual_pages = len(reader.pages)
        
        # Check page count if expected
        if expected_pages is not None and actual_pages != expected_pages:
            return False, f"Expected {expected_pages} pages, got {actual_pages}"
        
        return True, f"Valid PDF with {actual_pages} page(s)"
        
    except Exception as e:
        return False, f"PDF verification failed: {str(e)}"

# Example usage
pdf_files = [
    ("listings.pdf", 2),
    ("map.pdf", 1),
]

all_valid = True
for pdf_path, expected in pdf_files:
    valid, message = verify_pdf(pdf_path, expected)
    print(f"{pdf_path}: {'✓' if valid else '✗'} {message}")
    if not valid:
        all_valid = False

if not all_valid:
    raise Exception("PDF verification failed - review and regenerate")

3. Use run_shell for Verification

Execute the verification using run_shell:

python -c "
from PyPDF2 import PdfReader
import sys

pdf_path = 'output.pdf'
expected = 2

try:
    reader = PdfReader(pdf_path)
    actual = len(reader.pages)
    if actual != expected:
        print(f'ERROR: Expected {expected} pages, got {actual}')
        sys.exit(1)
    print(f'OK: {pdf_path} has {actual} page(s)')
except Exception as e:
    print(f'ERROR: {e}')
    sys.exit(1)
"

4. Verify Before Completion

Critical: Only mark your task as complete after ALL PDF verification checks pass. If verification fails:

1. Examine the error message
2. Regenerate the PDF with corrected formatting
3. Re-run verification
4. Repeat until all checks pass

Common Issues Caught

• Wrong page counts (e.g., content spilling to extra pages)
• Empty or corrupted PDF files
• PDFs that fail to open properly
• Missing expected sections due to formatting errors

Example Workflow

# 1. Generate PDF
generate_pdf("listings.pdf", content)

# 2. Verify before completion
valid, msg = verify_pdf("listings.pdf", expected_pages=2)
if not valid:
    # Fix and regenerate
    regenerate_pdf("listings.pdf", corrected_content)
    valid, msg = verify_pdf("listings.pdf", expected_pages=2)

# 3. Only complete if verification passes
assert valid, f"Cannot complete: {msg}"