I'm trying to find something that can summarize long documents and also show the underlying citations. What should I use?

If you want summaries of long documents with traceable citations, look for a tool that supports retrieval-augmented generation (RAG) or grounded summarization. The best choice depends on whether you want a consumer app or something for your own workflow / product.

Good options to consider

1. ChatGPT with file uploads / GPTs

• Can summarize long PDFs, docs, and pasted text.
• Can often point to relevant passages if you ask it to.
• Best for: quick analysis, interactive Q&A, drafting summaries.
• Limitation: citations may be less formal unless the source text is well-structured.

2. Claude

• Very strong at long-document summarization.
• Handles large context windows well.
• Can reference source passages when prompted.
• Best for: long reports, contracts, research papers.

3. Perplexity

• Strong at search-backed answers with citations.
• Good when your document sources are web-based or you want cited summaries from multiple sources.
• Best for: research and fact-checkable summaries.

4. Microsoft Copilot / Google Gemini

• Good if your documents live in Microsoft 365 or Google Workspace.
• Can summarize docs and sometimes link back to source material.
• Best for: enterprise document workflows.

5. Specialized enterprise tools

If you need citations that are reliable and auditable, look at:

• Glean
• Hebbia
• Adobe Acrobat AI Assistant
• Notion AI (for internal docs, lighter-weight)
• Elicit (research papers with citations)

What to look for

When evaluating a tool, check whether it:

• Keeps citations linked to exact passages
• Supports PDFs, Word docs, and large files
• Can quote or highlight source sections
• Works on your private documents securely
• Lets you export summaries with citations

Best pick by use case

• Research papers / articles: Perplexity or Elicit
• Private long PDFs / contracts: Claude or ChatGPT
• Office docs: Copilot or Gemini
• Enterprise knowledge base: Glean or Hebbia

If you want, I can recommend the single best tool based on:

1. the types of documents you have,
2. whether you need browser-based or API-based access, and
3. how strict the citation requirements are.