Reliable PDF Extraction

Reliable PDF Text Extraction

Problem

The read_file tool with filetype='pdf' often returns binary image data, errors, or unusable output when attempting to extract text from PDF documents. This makes it unreliable for structured data extraction tasks.

Solution

Use run_shell with command-line tools (pdftotext, pdfinfo) or execute_code_sandbox with Python libraries (PyMuPDF, pdfplumber) to extract PDF text content reliably.

Methods

Method 1: pdftotext (Recommended for simple extraction)

# Extract all text to stdout
pdftotext input.pdf -

# Or extract to file
pdftotext input.pdf output.txt
cat output.txt

Method 2: pdfinfo (For metadata)

pdfinfo input.pdf

Method 3: Python with PyMuPDF (fitz)

import fitz  # PyMuPDF

doc = fitz.open("input.pdf")
text = ""
for page in doc:
    text += page.get_text()
print(text)
doc.close()

Method 4: Python with pdfplumber (Better for tables/structured data)

import pdfplumber

with pdfplumber.open("input.pdf") as pdf:
    for page in pdf.pages:
        text = page.extract_text()
        print(text)
        # For tables:
        # tables = page.extract_tables()

Workflow

1. Attempt read_file with filetype='pdf' first (in case it works)

2. Check output - If you receive:

   • Binary/garbage data
   • Error messages
   • Empty or truncated content
   • Image data instead of text

3. Fall back to one of the extraction methods above:

   • Use pdftotext via run_shell for quick text extraction
   • Use pdfplumber via execute_code_sandbox for structured data/tables
   • Use PyMuPDF for complex layouts or when you need more control

4. Process the extracted text for your task

Example Usage

# Via run_shell
result = run_shell(command="pdftotext document.pdf -")
pdf_text = result.stdout

# Via execute_code_sandbox
code = """
import pdfplumber
with pdfplumber.open("/path/to/document.pdf") as pdf:
    for page in pdf.pages:
        print(page.extract_text())
"""
result = execute_code_sandbox(code=code)
pdf_text = result.stdout

Tips

• pdftotext is fastest and most reliable for plain text extraction
• pdfplumber excels at extracting tables and preserving layout
• PyMuPDF offers the most control for complex PDF structures
• Always check if the PDF is scanned/image-based (may need OCR tools like tesseract)
• Some PDFs have copy protection that may prevent text extraction