Petal
The one tool in this space that is a real reference manager first and a document chatbot second, which matters if citations are part of your output. If you only need to interrogate a handful of PDFs, a general assistant does that for free.
Pros
- Automatic metadata extraction and deduplication removes the worst part of library upkeep
- Sourced answers link back to the passage rather than paraphrasing without provenance
- Word add-in and browser importer cover the actual writing workflow, not just reading
- Paid entry price is a few dollars a month, far below research-AI subscriptions
Cons
- Free tier's 400 AI credits do not replenish, so it is a trial rather than a usable plan
- 1 GB of free storage fills fast with scanned PDFs
- Multi-document chat and AI Create are locked to the Advanced tier and above
- No API, so it cannot feed a lab's own pipelines