I gave an open-source PDF reader a local AI instead of paying Adobe $25 a month to chat with my PDFs
My local AI takes down another needless subscription on my statement
In 2024, Adobe integrated AI into its Acrobat product, allowing users to ask questions, get summaries, and navigate to specific pages of a PDF using the AI Assistant. This feature is bundled into Acrobat Studio at a monthly cost of $24.99, slightly higher than the $19.99 for Acrobat Pro. For comparison, the Claude Pro chatbot costs $5 per month, focusing solely on PDF-related conversations.
To bypass Adobe's costly AI offering, the author utilized their Claude Pro subscription ($5 less) to connect a local AI model with SumatraPDF, a free and open-source PDF reader. By leveraging Claude Code, the author developed a small helper app that connects Qwen3.6 with SumatraPDF. This setup enables any PDF opened on the user's PC to answer questions without sending any data outside the PC.
SumatraPDF lacks built-in plugin support but can achieve similar results using its advanced settings. The External Viewers setting allows opening the PDF in another application, while the Selection Handlers setting enables passing highlighted text to a website for processing. Both settings are configured in a plain text file accessible via SumatraPDF's Advanced Settings, eliminating the need for compilation.
The author configured both settings to use PyMuPDF for extracting text from each PDF page and Llama Server to run Qwen3.6-35B-A3B with 64K context, sufficient for their documents. Currently, the setup is configured so that Alt+1 opens a chat about the entire PDF, while highlighting text and pressing Alt+2, Alt+3, or Alt+4 retrieves the highlighted text's explanation, summary, or translation.
The model's responses are generated in a browser tab, and during testing, the author used a 62-page MSI B650M Gaming Plus Wi-Fi motherboard manual (62 pages, approximately 17K tokens). The first question took 12.5 seconds to answer, but subsequent questions were answered within 4 seconds due to the model not needing to re-read the entire document.
The author verified the model's answers by reading the manual, asking five questions, and receiving accurate responses every time, with correct page citations. The model correctly addressed a technical question about M.2 slots and SATA ports, citing the relevant manual page (18). In a fun experiment, the author asked if the motherboard could spontaneously combust, and Qwen3.6 honestly replied that the manual didn't mention it, directing the user to overheating warnings instead.
Lastly, the author tested the summarization feature, which faced limitations due to SumatraPDF's 1,000-character limit on highlighted text. The 3.7 pre-release version overcame this issue, allowing the full 1,531-character summary of a passage from A Scandal in Bohemia. The author emphasizes that this setup demonstrates how local AI can enhance open-source tools and replace features available only in paid applications.
Written by urgent.news from XDA Developers's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
