You've got a folder of PDFs and you want summaries — not by hand. Here are three approaches that actually work in 2026, roughly from "most control" to "least effort," plus an honest note on when you shouldn't build this at all.
Before any AI sees your PDF, two things bite you:
So the real pipeline is: extract → (OCR if needed) → chunk → summarize → reduce.
Good when you want full control over chunking, formatting, and cost.
import os
from pypdf import PdfReader
from openai import OpenAI
client = OpenAI(api_key=os.environ["OPENAI_API_KEY"])
def extract_text(path: str) -> str:
reader = PdfReader(path)
return "\n".join((page.extract_text() or "") for page in reader.pages)
def chunk(text: str, size: int = 12000, overlap: int = 500):
step = size - overlap
return [text[i:i + size] for i in range(0, len(text), step)]
def summarize_chunk(text: str) -> str:
resp = client.chat.completions.create(
model="gpt-4o-mini",
messages=[
{"role": "system", "content": "Summarize the text into concise bullet points. Keep names, numbers, and conclusions."},
{"role": "user", "content": text},
],
)
return resp.choices[0].message.content
def summarize_pdf(path: str) -> str:
text = extract_text(path)
if len(text.strip()) < 50:
raise ValueError("Almost no text extracted — this PDF is probably scanned. Run OCR first (see Approach 2).")
partials = [summarize_chunk(c) for c in chunk(text)]
combined = "\n\n".join(partials)
return summarize_chunk("Combine these section summaries into one structured summary:\n\n" + combined)
if __name__ == "__main__":
print(summarize_pdf("report.pdf"))
This is the classic map-reduce summarization pattern: summarize each chunk (map), then summarize the summaries (reduce). It scales to arbitrarily long documents.
Watch the token bill. Roughly, tokens ≈ characters / 4
. A 200-page PDF can be ~150k+ tokens of input alone, and map-reduce sends most of it at least once. On a cheap model that's cents; on a frontier model, dollars per document — multiply by your folder size before you for
-loop over 5,000 files.
If extract_text
comes back nearly empty, the pages are images. Add OCR:
import pytesseract
from pdf2image import convert_from_path
def ocr_pdf(path: str) -> str:
pages = convert_from_path(path, dpi=200)
return "\n".join(pytesseract.image_to_string(p) for p in pages)
Then feed that text into the same chunk → summarize
pipeline. OCR is slower and noisier, so expect to clean whitespace and the occasional garbled line.
If you'd rather not hand-roll chunking, langchain
and llama-index
wrap load → split → summarize:
from langchain_community.document_s import PyPDF
from langchain.chains.summarize import load_summarize_chain
from langchain_openai import ChatOpenAI
docs = PyPDF("report.pdf").load_and_split()
chain = load_summarize_chain(ChatOpenAI(model="gpt-4o-mini"), chain_type="map_reduce")
print(chain.invoke(docs)["output_text"])
Less code, less control. Fine for prototypes; for production I usually go back to Approach 1 so I own the prompts and the cost.
Here's the part most dev tutorials skip. Building the pipeline is worth it if you have volume, automation, or a product — thousands of files, a scheduled job, a feature in your app. It is not worth it if you just need to summarize a handful of documents occasionally. In that case you're maintaining OCR dependencies and paying API tokens to reinvent a form upload.
For the one-off / low-volume case, a free no-code summarizer is the pragmatic answer. There are a few: ** ChatPDF** and
| Your situation | Use |
|---|---|
| Thousands of files / scheduled job / product feature | Approach 1 (pypdf + API), add OCR as needed |
| Prototype, want minimal glue | Approach 3 (langchain/llama-index) |
| Scanned/image PDFs | Approach 2 (OCR) then any approach |
| A few docs, occasionally, no code to maintain | Free no-code tool (e.g. PDFSummarizer.net) |
chars/4
) What does your PDF pipeline look like? If you've found a cleaner chunking or OCR setup, I'd genuinely like to see it in the comments.
Tool details were accurate at the time of writing — check current limits before you rely on them.