Is Hjarni a real product?

Yes — Hjarni (hjarni.com) is a Markdown note knowledge base built for ChatGPT and Claude, with a native MCP server, web clipper, and folder-level AI instructions. This page only states features we could verify on their site.

Who should pick Hjarni?

If your workflow is mostly typing or clipping Markdown notes and you want folder-level instructions that ride along to the AI, Hjarni is purpose-built for that.

Who should pick BrainTube?

If most of your knowledge comes from watching, listening, and reading — and you want a memory layer that fills itself from videos, podcasts, PDFs and articles, plus a knowledge graph and spaced repetition — BrainTube is the better fit.

Yes. Both speak MCP. You could keep hand-written Markdown in Hjarni and let BrainTube own the media auto-capture side.

Comparison

BrainTube vs Hjarni

Both give your AI a knowledge base it can read over MCP. The difference is what gets in there. Hjarni is a clean Markdown note system you write into. BrainTube is a memory that fills itself from what you watch and read.

Quick verdict

Pick Hjarni if your knowledge is mostly typed Markdown and you want folder-level AI rules. Pick BrainTube if most of what you know comes from media you'd never sit down and type up — videos, podcasts, PDFs — and you want a knowledge graph + spaced repetition on top.

Capability	BrainTube	Hjarni
Notes you type / write in Markdown
Connects Claude & ChatGPT via MCP
Web clipper for articles
Auto-capture YouTube videos with transcripts
Auto-transcribe podcasts & audio you save
PDFs, EPUBs, meeting audio, screenshots
Postgres knowledge graph with PageRank retrieval
FSRS-5 spaced repetition built-in
Folder-level AI instructions that stack
Notes-update as a first-class MCP tool

yes · partial · no

Where Hjarni is genuinely strong

Hjarni leans hard into the Markdown-first, folder-instructions model. Their MCP exposes notes-update as a first-class tool, so the AI maintains and corrects notes instead of only appending. If your work product is the notes, that's a real edge.

What BrainTube adds

Auto-capture from media: YouTube transcripts, podcast audio, PDFs, EPUBs, web articles, Notion (4-hour sync), meeting audio, screenshots.
Knowledge graph: auto-linked entities in Postgres, PageRank-style retrieval.
FSRS-5 spaced repetition over the corpus.
MCP-native, listed in the official MCP registry and on Smithery.

Same MCP wedge, different shape

Both products agree on the bigger bet: your memory shouldn't live inside one chat app. The disagreement is whether the memory should be hand-curated Markdown (Hjarni) or auto-compiled from what you already consume (BrainTube).

Frequently asked

Is Hjarni a real product?: Yes — Hjarni (hjarni.com) is a Markdown note knowledge base built for ChatGPT and Claude, with a native MCP server, web clipper, and folder-level AI instructions. This page only states features we could verify on their site.
Who should pick Hjarni?: If your workflow is mostly typing or clipping Markdown notes and you want folder-level instructions that ride along to the AI, Hjarni is purpose-built for that.
Who should pick BrainTube?: If most of your knowledge comes from watching, listening, and reading — and you want a memory layer that fills itself from videos, podcasts, PDFs and articles, plus a knowledge graph and spaced repetition — BrainTube is the better fit.
Can I use both?: Yes. Both speak MCP. You could keep hand-written Markdown in Hjarni and let BrainTube own the media auto-capture side.

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