Cosmica
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AI Native · Markdown · Local-first

A Markdown Notefor AI Native

The format AI reads best and understands best — plain Markdown. Voice memos, messenger pings, meeting notes, stray ideas — all pile into one file tree and become your personal knowledge base.

Download for macOS
Cosmica-design.md
+
dev/Cosmica-design.mdSaved

Claude CLI · Auto summaryclaude -p "summarize"

example demo
Why Markdown

The language AI understands best,
Markdown

Claude, GPT, Gemini — the structured format every frontier LLM saw most during training is Markdown. Headings, lists, code blocks, links: structure carries directly as meaning. Cosmica stores every input as a .md file so your thoughts accumulate in a format that models read natively.

One Format, Many Sources
🎙 Voice memo
💬 Telegram / Slack
📝 Meeting notes
✍️ Direct writing
.md
single source
Claude
reads directly
voice-memo-20260414.md
## Voice memo summary — 2026-04-14 09:32

**Transcript**
> Applying dependency inversion from
> clean architecture to Cosmica…

**Summary**
- Domain layer knows nothing about the outside
- Communicate only through adapters
- File I/O abstracted behind port interfaces

**Tags**
#AI #Cosmica

**Related notes**
[[Cosmica-design]] [[AI-ideas]]
AI-friendly format
Instead of HTML or proprietary blobs, Markdown is what LLMs parse cleanest token-for-token. Zero noise when injected as prompt context.
No lock-in
Every note is a plain text file. Opens identically in Obsidian, VS Code, or any tool you prefer.
One place for knowledge
Voice, messenger, meetings, manual — however it enters, it lands in the same tree and the same tag graph.
What's inside

Notes and AI, fused from day one

Obsidian's data sovereignty, Notion's smooth editor, Claude's reasoning — all of it, none of it forced.

Voice → note

Record and Whisper STT, AI summary, and tag extraction are written to Markdown automatically.

Markdown editor

Milkdown WYSIWYG + CodeMirror source mode. Files are the source of truth.

Local AI on your machine

Auto-detects your installed Claude Code · Codex CLI, or talks to the Anthropic API directly. Keep the AI setup you already use — no extra subscription.

Knowledge graph

Backlink and tag graphs in one view. D3 force-directed, up to 500 nodes.

Full-text search (⌘K)

SQLite FTS5 with tag · folder · source filters and a ⇧⌘K command palette.

Messenger bot inbox

Slack · Telegram · Discord send into notes — and notes can be sent back to channels.

NotebookLM integration

MCP-based uploads. Raw or AI-condensed mode, tag-bundled batch export.

Multi-device sync

Keep devices in sync through Google Drive or a GitHub repo (gh CLI).

Mobile bridge

One QR pairs your phone over Wi-Fi or Tailscale, so the desktop Claude CLI answers straight from your mobile — no cloud relay.

Canvas · calendar

Whiteboard and a created/modified-date calendar view.

Voice Memo

Captured as you speak,
summarized on arrival

Record → STT → AI summary → tag extraction → Markdown save. The whole pipeline runs from a single click. The transcript is always preserved; extracted tags can be edited anytime.

  • Whisper.cpp · Web Speech API
    Defaults to the Web Speech API; switch to local Whisper when you need offline and higher accuracy.
  • Customizable summary prompts
    Edit the template to match your project, team, or personal voice.
  • Auto-save option
    5-second preview then auto-save. Raw audio is kept as WebM under ~/CosmicaNotes/Voice.
VoiceMemo
+
00:42
Whisper.cpp
example demo
Markdown Editor

Files are the source.
The editor assists.

Milkdown-based WYSIWYG, but what gets saved is plain Markdown. Open the same file in VS Code, Obsidian, or anywhere else — it just works.

  • [[Backlink]] autocomplete
    Type double brackets to link notes. Indexes refresh on save and propagate to the graph.
  • #tag recognition
    Inline tags are extracted automatically; sidebar, graph, and export stay in sync.
  • Folder drag & drop
    Reorganize in the sidebar tree — every change is a real file system move.
Cosmica-design.md
+
dev/Cosmica-design.md

Cosmica design notes

#architecture#AI#local-first#TODO

Markdown files are the source of truth; the DB is only a cache. Storing everything in an AI-readable format is the core principle.

Backlink syntax like [[voice-memo-20260414]] is auto-completed, and the tag index refreshes on save.

  • Milkdown WYSIWYG + Markdown compatible
  • #tag recognition → propagates to graph view
  • Injectable as context straight to Claude CLI
example demo
Knowledge Graph

Your own constellation,
stitched by tags

A D3 force-directed graph surfaces the relationships across your notes at a glance. Node size scales with connections; colors group by tag.

  • Tag filters
    Narrow the view to a subset of tags to zoom into a topic.
  • Click to open
    Click a node to jump straight into that note.
  • Incremental indexing
    Indexes update only on save, keeping things light even with thousands of notes.
Graph View
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Graph View · 6 notes · 4 tags
example demo
Multi-device Sync

Your notes move only through
your drive

Cosmica runs no servers and holds no accounts. Sync happens through your own Google Drive or a GitHub repository you control. Desktop, laptop, studio, home — the same Markdown tree flows inside your cloud, and nowhere else.

  • Google Drive · GitHub Repo
    Pick the Google Drive API (OAuth) or any GitHub repo authenticated through the gh CLI. Multi-device sync follows the same rules either way.
  • Auto-bootstrap GitHub repos
    Browse and pick from your gh-authorised repos. Empty repos get a README and a sync marker committed automatically; non-Cosmica repos are safely refused.
  • Per-kind targets
    Toggle Markdown, attachments, and audio independently. Keep raw audio local, sync only the notes — up to you.
  • MD5 incremental + conflict keep-both
    Only changed bytes leave the machine. When both sides changed, Cosmica keeps both copies so you merge deliberately.
Sync · Multi-device
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Multi-device Sync

Google Drive · GitHub Repo · no relay

Google Drive
Live·just now
GitHub Repo
Live·4 min ago
Targets
MarkdownAttachmentsAudio
Recent activity
  • Cosmica-design.mdGoogle Drive
  • voice-memo-20260414.mdGitHub Repo
  • Attachments/2026-04/diagram.pngGoogle Drive
example demo
AI Integration

Use the Claude Codeyou already have
installed

On launch, Cosmica detects your installed Claude Code CLI and Codex CLI automatically. No extra API keys, no extra subscriptions. Output streams in via SSE and lands straight into the note.

  • CLI auto-detection + priority
    Claude → Codex → API fallback. Reorder in settings.
  • Five AI actions
    Summarize · suggest tags · find related notes · expand ideas · generate Q&A.
  • Token-thrifty indexing
    Sends title + tags + first 200 chars, not the full body — cheap and fast.
Claude Code CLI detected · v1.4.2Codex CLI fallback
AI actions
  • Summarize
  • Suggest tags
  • Related notes
  • Expand ideas
  • Generate Q&A
claude -p "Summarize this note in 3 lines…"

Cosmica uses the local Claude CLI as its backend to deliver an AI notes environment without cloud dependencies.

The file system is the source; the DB is a cache — notes remain shareable with any other editor.

Tag and backlink indexes refresh incrementally on save, so it stays fast at any scale.

312 tokens · 1.2s responseAdd to note
Mobile Bridge

From mobile, your
desktop Claude as-is

Scan one QR and your phone is wired directly to the desktop over the same Wi-Fi or Tailscale. No new subscription, no cloud relay. AI calls reuse the Claude CLI already installed on your desktop; notes travel only between your two devices.

  • One-shot 60-second code
    The QR only ever mints a 256-bit bearer token once and is burned on first use. A photo of it cannot be replayed.
  • Tailscale · LAN auto-detection
    CGNAT (100.64/10), RFC1918, and link-local are all detected so the phone connects over whichever path is available. No external servers.
  • Desktop AI from mobile
    Run summarize, suggest tags, related notes from your phone; the desktop Claude CLI answers and streams the tokens back via SSE.
Mobile Pairing
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Mobile pairing

Scan the QR → talk straight to desktop

Pairing code
a3f9·bc10·de22
expires in 48s
Detected routes
  • Tailscale100.101.42.7 · CGNAT
  • LAN192.168.1.24 · en0
Paired devices
  • iPhone (Ray)
    Tailscale · just now
  • iPad
    LAN · Wi-Fi · 3h ago
example demo
Bot Collector

Messages sent on the go
land in the same notes

Send via Slack, Telegram, or Discord and Cosmica receives and records it as a note. Attachments and images are organized under ~/CosmicaNotes/Attachments by date.

  • Webhook or polling
    Polling by default so it works on laptops without public IPs.
  • Per-message or daily digest
    One file per message or one rolling file per day — your choice.
  • Auto-summarize on receive
    Trigger AI summary + tag extraction on ingestion so notes arrive already tidy.
Inbox · Bot Collector
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Bot Inbox

Incoming from Telegram · Slack · Discord

Polling · 30s
  • TelegramToday 09:15

    Idea on the subway: add automated weekly-review prompts to Cosmica

    #idea#TODO
  • SlackToday 11:02

    Meeting note — need a fallback path when AI summary accuracy is low

    #meeting#AI
  • DiscordYesterday 22:41

    Saving links from the thread (3 attachments)

    #reference
example demo
NotebookLM Export

Ready to
upload straight into NotebookLM

Merge a tag’s notes into a single Markdown, and auto-split into 200,000-character chunks. Cuts happen only at note boundaries so context never breaks.

  • Merge by tag
    Pick #AI, #architecture, or any combination to build the bundle.
  • Note-boundary splitting
    Files split only at natural boundaries so no note is cut mid-sentence.
  • Markdown / PDF export
    The same pipeline handles sharing and backup.
Export · NotebookLM
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NotebookLM Export

Bundle by tag, split at 200,000 chars

Selected tags
#AI#Cosmica#TODO
Notes included
27
Total characters
312,480
Split files
2
Output files
  • AI_notes_01.md
    200,000 chars
  • AI_notes_02.md
    112,480 chars
example demo
Your data, your files

Your thoughts,
on your disk

No signup, no Cosmica account. The source is always a Markdown file in your home directory. Sync is opt-in, and when you turn it on, your data only moves through your own Google Drive or a GitHub repo you own.

~/CosmicaNotes
~/CosmicaNotes/
├── Note/
│   ├── dev/
│   │   ├── Cosmica-design.md
│   │   └── voice-memo-20260414.md
│   ├── ideas.md
│   └── inbox/
│       └── inbox-20260414.md
├── Audio/
├── Attachments/
├── Canvas/
└── .trash/

~/.cosmica/
├── config.json
├── cosmica.db
└── whisper/
No Cosmica account
No server of ours. Launch the app and start writing — there's nothing to sign into.
Offline first
Whisper + local Claude CLI keep the core features working without internet.
Sync through your cloud
Flip on Google Drive or a GitHub repo only when you need it. No relay in the middle.
Own your exit
Files are the data. Delete the app — your .md notes stay.
Ready to begin

Turn your notes
into a constellation

Apple Silicon builds for macOS. Install, launch, done — no account, no configuration.

Cosmica for macOS