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Claude-Nebula

A Claude Code plugin that gives Claude persistent semantic memory across sessions, powered by Nebula. Every conversation is automatically captured and stored in Nebula. When you need to recall something from a past session — what you worked on, how something was implemented, a decision you made — Claude can search your memory and bring it back.

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How It Works

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Automatic Capture

The plugin hooks into two Claude Code lifecycle events:
  • UserPromptSubmit — captures new messages each time you send a prompt
  • Stop — captures any remaining messages when Claude finishes responding
Messages are sent to Nebula as conversation memories using storeMemories(). Nebula handles chunking, embedding, ranking, deduplication, and knowledge graph extraction server-side. The plugin tracks what has already been sent per session so nothing is duplicated. Use the /nebula-search slash command to search across all stored sessions: 
/nebula-search "how did we set up authentication?"
This performs a semantic search over your collection and returns the most relevant conversation fragments, ranked by activation score.

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Codebase Indexing

Use /index to have Claude explore your codebase and store a comprehensive summary (architecture, conventions, key files) into Nebula for future reference.

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Setup

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1. Get a Nebula API Key

Sign up at trynebula.ai and create an API key from your dashboard.

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2. Create a Collection

Create a collection in Nebula (via the dashboard or API). Copy the collection ID — this is where your memories will be stored.

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3. Configure Credentials

Create the settings file: 
mkdir -p ~/.nebula-claude
cat > ~/.nebula-claude/settings.json << 'EOF'
{
  "apiKey": "your-nebula-api-key",
  "collectionId": "your-collection-id"
}
EOF
Alternatively, use environment variables (these override the settings file): 
export CC_NEBULA_API_KEY="your-nebula-api-key"
export CC_NEBULA_COLLECTION_ID="your-collection-id"

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4. Install the Plugin

git clone https://github.com/nebula-agi/claude-nebula.git
cd claude-nebula
npm install
npm run build
claude plugin install ./plugin
The build step bundles the source files into plugin/scripts/*.cjs using esbuild.

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5. Verify

Start a new Claude Code session. The capture hooks will run automatically in the background. Try a search to confirm everything is connected: 
/nebula-search "test"

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Configuration Reference

Settingsettings.json keyEnvironment variableRequired
API KeyapiKeyCC_NEBULA_API_KEYYes
Collection IDcollectionIdCC_NEBULA_COLLECTION_IDYes
Debug loggingdebugCC_NEBULA_DEBUG=trueNo
Settings file location: ~/.nebula-claude/settings.json Environment variables take precedence over the settings file.

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Slash Commands

CommandDescription
/nebula-search "query"Search your memory for relevant past conversations
/indexIndex your current codebase into Nebula
/logoutClear saved Nebula credentials