.md files into a linked knowledge graph. Free for all use cases, including commercial.Obsidian — Knowledge Management for AI Workflows
Obsidian operates entirely on your local filesystem: plain .md files in a folder, no database, no server, no vendor lock-in. This makes it uniquely suited for LLM memory systems — the same files an AI reads and writes are the ones you browse in the editor.
How Obsidian Works
| Property | Details |
|---|---|
| Storage | Plain .md files in a folder |
| Database | None — the filesystem IS the database |
| Server | None required — works 100% offline |
| Vendor lock-in | Zero — any text editor reads your notes |
| Platforms | Windows, macOS, Linux, iOS, Android |
| License | Free (personal and commercial) |
The Vault Concept
An Obsidian vault is simply a directory on disk. Obsidian creates a .obsidian/ subdirectory for settings and indexes all markdown files.
my-vault/
├── .obsidian/ # Settings, plugins, themes
├── Daily/ # Daily notes
├── Projects/ # Active project context
├── Knowledge/ # Distilled reference material
└── Templates/ # Note templates
On vault open, Obsidian: scans all .md files, parses YAML frontmatter, indexes all [[wiki-links]] to build the link graph, caches the index for fast search, and watches the filesystem for external changes.
Core Features
| Feature | What It Does |
|---|---|
| Graph View | Interactive visual map of notes and link connections |
| Backlinks | Every note that links TO the current note |
| Search | Full-text with regex, tag, path, property filters |
| Tags | #tag inline or frontmatter; hierarchical: #project/scraper |
| Canvas | Visual board for arranging notes spatially |
| Bases | Native database views over your notes (2025) |
| Daily Notes | One note per day, auto-created from template |
| Properties | Visual editor for YAML frontmatter fields |
The Linking System
[[Note Name]] # Link to a note
[[Note Name#Heading]] # Deep link to heading
[[Note Name|Display Text]] # Custom display text
![[Note Name]] # Embed (transclusion)
![[image.png]] # Embed image
When note A links to note B, Obsidian automatically creates a backlink in note B. This builds a knowledge graph where you navigate in any direction.
Essential Plugins
| Plugin | What It Does |
|---|---|
| Dataview | SQL-like queries over frontmatter and content |
| Templater | Advanced templates with JavaScript and dynamic dates |
| obsidian-git | Auto-commit and push to Git on interval |
| Calendar | Visual calendar linked to daily notes |
| Tasks | Track tasks across all notes with due dates |
AI-Focused Plugins
| Plugin | What It Does |
|---|---|
| Smart Connections | AI-powered similar note discovery via vector embeddings |
| Copilot | Chat with LLM inside Obsidian using vault as RAG context |
| Khoj | Self-hosted AI assistant with full vault indexing |
| AI LLM | Integrates Ollama and local models for text expansion |
Vault Structure for AI Workflows
vault/
├── 00-Inbox/ # Raw captures, unsorted
├── 01-Projects/ # Active project context
│ └── project/_MOC.md # Map of Content (index)
├── 02-Knowledge/ # Distilled, reusable knowledge
├── 03-Runbooks/ # Step-by-step procedures
├── 04-People/ # Contact/team context
├── 05-Context/ # LLM-specific context files
│ ├── PERSONA.md # Your preferences and stack
│ ├── CONVENTIONS.md # Coding conventions
│ └── STACK.md # Current tech stack
├── Daily/ # Daily notes
├── Templates/ # Note templates
└── _Index.md # Master Map of Content
Obsidian as LLM Memory
This is the highest-value use case. Obsidian becomes the persistent memory layer for LLM interactions.
The Three-Layer Memory Architecture
Layer 1: Episodic Memory — What Happened
Layer 2: Semantic Memory — What You Know
Layer 3: Procedural Memory — How to Do Things
Feeding Your Vault to an LLM
The simplest approach for tools with file access (Claude Code, Cursor, Aider):
## Memory System (add to CLAUDE.md)
- At session start, read 05-Context/PERSONA.md
- Before working on any project, read its _MOC.md first
- After significant work, write a session-handoff note
- When learning something reusable, create a note in 02-Knowledge/
For large vaults (500+ notes), use Retrieval-Augmented Generation:
Vault (.md files)
→ embed with text-embedding-3-small
Vector Database (ChromaDB, Qdrant, Pinecone)
→ similarity search (top-K relevant chunks)
LLM generates answer with vault context
Plugins: Smart Connections (local), Copilot (OpenAI/Anthropic), Khoj (self-hosted).
Connect Claude Desktop or Claude Code to your vault via MCP:
- Install Local REST API plugin in Obsidian
- Configure MCP server in Claude config
- The AI can search, read, create, and update notes autonomously
Available tools: list_files_in_vault, get_file_contents, search_vault, create_file, append_content
Git Version Control
Setup with obsidian-git plugin
Install: Settings > Community Plugins > Browse > "Obsidian Git" > Install > Enable
| Setting | Recommended Value |
|---|---|
| Auto backup interval | 15 minutes |
| Auto pull on open | Enabled |
| Commit message format | vault backup: {{date}} |
| Push on backup | Enabled |
.gitignore (critical):
.obsidian/workspace.json
.obsidian/workspace-mobile.json
.obsidian/cache/
.DS_Store
Thumbs.db
Writing Notes for Machines
Best Practices for LLM-Readable Notes
Structured over narrative:
---
type: learning
domain: scraping
confidence: verified
date: 2026-02-24
---
## JWT Token Expiration
- Expiry: ~2 hours from issuance
- Detection: HTTP 401 during scraping
- Mitigation: Call is_token_valid() before each batch
One idea per note (atomic notes) — the LLM retrieves precisely what it needs.
Consistent frontmatter schema:
title: string # Human-readable title
type: enum # learning | decision | runbook | reference | daily
domain: string[] # Topic areas
status: enum # seed | growing | evergreen
confidence: enum # hypothesis | tested | verified
Obsidian vs. Alternatives
| Criteria | Obsidian | Notion | Logseq |
|---|---|---|---|
| Local-first | Yes | No | Yes |
| Plain files | Yes (markdown) | No (proprietary) | Yes |
| LLM integration | Excellent (file + MCP) | API only | Good |
| Git-friendly | Excellent | No | Good |
| Plugin ecosystem | 2,700+ | Integrations | 200+ |
| Free tier | Full features | Limited | Full features |
| If you need… | Choose |
|---|---|
| LLM memory system | Obsidian |
| Team wiki / database | Notion |
| Daily journaling / outliner | Logseq |
| Simplest setup | Obsidian |
| Privacy-first AI | Obsidian |