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PDFpal

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What PDFpal is

PDFpal is a free, local PDF reader that adds AI chat, notes, highlights, and a scriptable command-line interface. Its split-pane reader keeps a document beside chat, notes, and related papers, and remembers the last page for each source. Users can question a passage, a paper, or selected sources across a project; responses are grounded in retrieved paper text and include source citations. Projects hold sources, notes, and chat history, while nested collections organize sources inside a project. Highlights and Markdown notes can be saved at project or source level. Paper search uses OpenAlex, and related-paper discovery uses Semantic Scholar with an OpenAlex fallback. The resolver accepts arXiv, OpenReview, ACL Anthology, PMLR, DOI, and direct PDF links. The CLI supports JSON output and agent skills for Claude Code and Codex. PDFpal runs on the user’s machine, stores data under ~/.pdfpal by default, and does not upload PDFs to cloud services. It requires Node.js 22 or newer and an authenticated Claude, Codex, or OpenCode CLI.

Who it suits

It suits researchers and other single users who want local PDF work with AI-assisted questioning, citations, notes, and paper discovery. It is also useful for scripted or agent-driven workflows.

What it does well

  • Local storage and no cloud PDF uploads
  • Chat across selected project sources
  • Source citations in retrieved-paper answers
  • Projects, collections, highlights, and Markdown notes
  • Free with no SaaS fee or usage cap

What to know first

  • Requires Node.js 22 or newer
  • Requires an authenticated agent CLI
  • AI use depends on an existing agent subscription
  • Intended for local, single-user operation

Verdict

PDFpal combines local document control with project-based research chat and scripting. Its lack of SaaS fees and usage caps is paired with setup requirements and dependence on a separate agent subscription.

Facts from PDFpal's own pages

AI providers
It works with installed and authenticated Claude, Codex, or OpenCode command-line tools. · github.com, 9 Oct 2026
Annotations
Users can save highlights and write Markdown notes at project or source level. · github.com, 4 Oct 2026
Automation
The CLI supports JSON output, and the repository provides a Claude Code and Codex skill for agent-driven workflows. · github.com, 4 Oct 2026
Chat
Users can ask questions about a passage or across selected sources in a project, with answers grounded in retrieved paper text. · github.com, 4 Oct 2026
CLI and agents
The CLI supports scripting with JSON output, and the project provides a skill for Claude Code and Codex agents to manage projects, sources, collections, and notes. · github.com, 9 Oct 2026
Integrations
PDFpal supports the Claude, Codex, and OpenCode agent CLIs and uses OpenAlex and Semantic Scholar for discovery. · github.com, 4 Oct 2026
Limits and fees
The maker says PDFpal has no SaaS fee, usage caps, or feature gates; AI use depends on the user's existing agent subscription. · github.com, 9 Oct 2026
Local data
PDFpal stores its database, managed PDF copies, and backups locally under ~/.pdfpal by default. · github.com, 4 Oct 2026
Local storage
PDFpal stores its database, managed PDF copies, and extracted text locally under ~/.pdfpal by default. · github.com, 9 Oct 2026
Organization
Users can organize sources into projects and nested collections, and keep project or source notes and highlights. · github.com, 9 Oct 2026
Paper discovery
Paper search uses OpenAlex, while related-paper results use Semantic Scholar with an OpenAlex fallback. · github.com, 9 Oct 2026
PDF sources
The PDF resolver accepts links from arXiv, OpenReview, ACL Anthology, PMLR, DOI links, and direct PDF URLs. · github.com, 9 Oct 2026
Privacy and deployment
The README says the app runs on the user's machine and does not upload PDFs to a cloud service; it is intended for local, single-user operation. · github.com, 4 Oct 2026
Privacy and operation
The maker says PDFpal runs on the user's machine without uploading files to a cloud service and is intended for local, single-user operation. · github.com, 9 Oct 2026
Product
PDFpal is a local PDF reader with AI chat, notes, highlights, and a scriptable CLI. · github.com, 4 Oct 2026
Purpose
PDFpal is a local PDF reader with AI chat, notes, highlights, and a scriptable CLI. · github.com, 9 Oct 2026
Reading
The split-pane reader places the PDF beside chat, notes, and related papers, and remembers each source’s last page. · github.com, 4 Oct 2026
Reading and chat
The split-pane reader supports questions about selected passages, per-paper chat, and questions across project sources. · github.com, 9 Oct 2026
Requirements
PDFpal requires Node.js 22 or newer and an installed, authenticated supported agent CLI. · github.com, 9 Oct 2026
Usage limits
The README states there is no SaaS fee, usage cap, or feature gate; AI use goes through the user's existing agent subscription. · github.com, 4 Oct 2026

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