Obsidian gives you total freedom over how you organize notes, with plugins for nearly everything, including project logs. ContextOS trades that freedom for a fixed structure — sessions, decisions, ideas, next step — built around one job: getting you back into a project fast.
Where Obsidian wins
Local-first files you fully own
Huge plugin ecosystem and graph view
Great for permanent, cross-referenced knowledge
Where ContextOS wins
Purpose-built structure, no setup or plugin-hunting required
AI-generated resume brief instead of manually re-reading notes
Designed around resuming, not just note-taking
Side by side
Feature
Obsidian
ContextOS
Primary purpose
Local-first linked notes
Structured project memory
Session history
Manual daily notes
Built-in, first-class
Decision log with reasons
Manual notes
Built-in
Resume after time away
Browse your graph
AI resume briefing
Storage
Local markdown files
Cloud, private to your account
Best for
Long-term personal knowledge
Per-project state & next actions
The honest take
If you already have an Obsidian vault with a working project-log template, ContextOS may feel redundant. If you've tried to build that system in Obsidian and it decayed after a few weeks, ContextOS removes the setup burden entirely.
Some combination of daily notes, templates, and plugins can get close, but it requires ongoing maintenance. ContextOS ships the structure by default.
ContextOS isn't a note vault replacement — most people keep Obsidian for permanent notes and use ContextOS specifically for the resume-a-project layer.
No — it's a hosted web app, not a local-first tool. That's a real tradeoff if offline access matters to you.
Depends on whether your bottleneck is organizing knowledge (Obsidian) or resuming stalled projects fast (ContextOS).