Cipher
Cipher is an opensource memory layer specifically designed for coding agents. Compatible with Cursor, Windsurf, Claude Desktop, Claude Code, Gemini CLI, AWS's Kiro, VS Code, and Roo Code through MCP, and coding agents, such as Kimi K2.
What is Cipher?
Cipher is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to cipher is an opensource memory layer specifically designed for coding agents. compatible with cursor, windsurf, claude desktop, claude code, gemini cli, aws's kiro, vs code, and roo code through mcp, ...
Cipher is an opensource memory layer specifically designed for coding agents. Compatible with Cursor, Windsurf, Claude Desktop, Claude Code, Gemini CLI, AWS's Kiro, VS Code, and Roo Code through MCP, and coding agents, such as Kimi K2.
This server falls under the Knowledge & Memory category on MCPgee, the world's largest MCP server directory with 33,000+ servers.
Features
- Cipher is an opensource memory layer specifically designed f
Use Cases
Maintainer
Works with
Installation
Manual Installation
npx ryanngConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use Cipher
Cipher (published under the ryanng slug) is an open-source memory layer designed specifically for coding agents, providing persistent context and knowledge storage across sessions. It integrates with major AI coding environments — Cursor, Windsurf, Claude Desktop, Claude Code, Gemini CLI, VS Code, Roo Code, and AWS Kiro — through the Model Context Protocol, as well as directly with coding agents like Kimi K2. Cipher lets agents remember architectural decisions, coding conventions, authentication patterns, and project-specific context without repeating them in every prompt.
Prerequisites
- Node.js 18+ or a compatible runtime for npx-based installation
- An MCP-compatible coding client such as Cursor, Claude Desktop, or VS Code with an MCP extension
- curl for the shell-based installer (macOS or Linux)
- A project directory where the memory layer will store context
Install ByteRover CLI (the runtime backing Cipher)
Install the brv CLI globally using npm, or use the shell installer for macOS and Linux. The brv binary provides all memory management commands.
npm install -g byterover-cli
# or via shell installer:
curl -fsSL https://byterover.dev/install.sh | shVerify installation
Check that the brv binary is correctly installed and accessible in your PATH.
brv --versionInitialize Cipher in your project
Navigate to your project directory and run brv to initialize the memory layer. The first run sets up the local knowledge store and configuration.
cd /path/to/your/project
brvConfigure your MCP client to use Cipher
Add Cipher as an MCP server in your client configuration. Because it is run as npx ryanng, the memory layer is loaded as an MCP tool provider.
{
"mcpServers": {
"cipher": {
"command": "npx",
"args": ["ryanng"]
}
}
}Add context to the knowledge store
Use the curate command to store important project knowledge — architectural decisions, coding patterns, API conventions — that the agent should remember across sessions.
brv curate "Auth uses JWT with 24h expiry" @src/middleware/auth.tsQuery stored context
Use the query command to retrieve stored knowledge, or let the MCP-connected agent automatically access relevant context when answering questions.
brv query "How is authentication implemented?"Cipher Examples
Client configuration
Claude Desktop configuration for the Cipher memory MCP server.
{
"mcpServers": {
"cipher": {
"command": "npx",
"args": ["ryanng"]
}
}
}Prompts to try
Use Cipher's memory layer through your MCP-connected coding assistant.
- "What authentication pattern does this project use?"
- "Remember that we use snake_case for database column names in this project"
- "What were the architectural decisions made last week for the payment module?"
- "Store the fact that this API uses OAuth2 with PKCE for user-facing endpoints"Troubleshooting Cipher
brv command not found after npm install -g
Check your npm global bin directory with npm bin -g and ensure it is in your PATH. On macOS this is typically /usr/local/bin or ~/.npm-global/bin. You may need to run: export PATH=$(npm bin -g):$PATH
MCP client shows the Cipher server as disconnected
Verify that npx ryanng launches successfully from the terminal. If there are network issues fetching the package, try installing globally first with npm install -g byterover-cli and then referencing the brv binary directly in the MCP config.
Context stored in one session is not available in another
Check that BRV_DATA_DIR is consistently pointing to the same directory across sessions. By default, data is stored in a platform-specific location. Set BRV_DATA_DIR explicitly in the MCP server env config to pin the location.
Frequently Asked Questions about Cipher
What is Cipher?
Cipher is a Model Context Protocol (MCP) server that cipher is an opensource memory layer specifically designed for coding agents. compatible with cursor, windsurf, claude desktop, claude code, gemini cli, aws's kiro, vs code, and roo code through mcp, and coding agents, such as kimi k2. It connects AI assistants to external tools and data sources through a standardized interface.
How do I install Cipher?
Follow the installation instructions on the Cipher GitHub repository. Clone the repo, install dependencies, and add the server config to your AI client.
Which AI clients work with Cipher?
Cipher works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is Cipher free to use?
Yes, Cipher is open source and available under the Elastic License 2.0 license. You can use it freely in both personal and commercial projects.
Cipher Alternatives — Similar Knowledge & Memory Servers
Looking for alternatives to Cipher? Here are other popular knowledge & memory servers you can use with Claude, Cursor, and VS Code.
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