What is the key difference between Ratary and Cosmos MCP?

Ratary belongs to the Knowledge & Memory category with local stdio execution, while Cosmos MCP belongs to the Knowledge & Memory category with local stdio execution.

How do I install Ratary or Cosmos MCP in Claude Desktop or Cursor?

Copy the mcpServers JSON configuration snippet provided on this page into your claude_desktop_config.json or ~/.cursor/mcp.json file and restart your AI client.

Are Ratary and Cosmos MCP free or paid?

Ratary operates under a Free / Open Source model (API Key required). Cosmos MCP operates under a Free / Open Source model (API Key required).

Which MCP server has more tools and community activity?

Ratary lists 6 tools with 3 views and 1 GitHub stars. Cosmos MCP lists 6 tools with 3 views and 3 GitHub stars.

Can I use both Ratary and Cosmos MCP together in the same MCP host?

Yes! MCP hosts like Claude Desktop, Cursor, Windsurf, Cline, and VS Code support configuring multiple servers under the mcpServers object simultaneously.

Side-by-Side Model Context Protocol Comparison

Ratary vs Cosmos MCP

In-depth architectural comparison of the Ratary and Cosmos MCP MCP servers. Compare execution transports, security boundaries, tool capabilities, quality scores, and ready-to-paste client installation snippets for Claude, Cursor, Windsurf, and VS Code.

At a Glance & Executive Verdict

Ratary

Knowledge & Memory · Local stdio

Quality: 49/100 (Fair) | Auth: API Key required

Cosmos MCP

Knowledge & Memory · Local stdio

Quality: 56/100 (Good) | Auth: API Key required

Verdict Summary: Choose Ratary if you need specialized Knowledge & Memory tools running via a local process. Choose Cosmos MCP if your workspace requires Knowledge & Memory integration with local subprocess execution. Both servers can be configured concurrently in your client's mcpServers manifest.

Which MCP Server Should You Choose?

Choose Ratary when:

You need dedicated capabilities in the Knowledge & Memory domain.
You prefer local stdio subprocess transport architecture.
Your security boundary fits: API Key required (Free / Open Source).
You have access to required keys: AUTH_SECRET, DATABASE_URL, SQL_PROVIDER, RATARY_BASE_URL, RATARY_API_KEY.
Primary tools included: Persistent versioned memory, Hybrid search and context assembly, Structured metadata and knowledge graphs.

Explore Ratary Details

Choose Cosmos MCP when:

You need dedicated capabilities in the Knowledge & Memory domain.
You prefer local stdio subprocess transport architecture.
Your security boundary fits: API Key required (Free / Open Source).
You have access to required keys: COSMOS_TOKEN.
Primary tools included: .

Feature & Specification Comparison

Specification	Ratary ontorata Knowledge & Memory	Cosmos MCP teampolarity Knowledge & Memory
Summary	Persistent coding memory for AI assistants — hybrid search, knowledge graph, token-efficient context. MCP stdio (28 tools), npm @ratary/mcp-server, optional remote Streamable HTTP. Self-host D1, Postgres, MariaDB, or Docker.	Personal knowledge graph shared across MCP clients. Account-keyed and portable as a .polarity file, with sources for iMessage, browser history, calendar, Claude Desktop transcripts, shell history, Notion, and Obsidian. npx -y @polarity-lab/cosmos-mcp
Category & Scope

Tools & Capabilities Breakdown

Ratary Tools (6)

Persistent versioned memory

Hybrid search and context assembly

Structured metadata and knowledge graphs

28 MCP tools

Self-hosted SQL storage

Optional remote Streamable HTTP

Cosmos MCP Tools (6)

Shared account-keyed personal knowledge graph

Ready-to-Paste Client Configurations

Paste either (or both) of these JSON server blocks into your client config file (e.g. claude_desktop_config.json or ~/.cursor/mcp.json).

Ratary Configuration

mcpServers (Claude Desktop / Cursor)

{
  "mcpServers": {
    "ontorata-ratary": {
      "command": "npx",
      "args": [
        "-y",
        "@ratary/mcp-server@1.1.3"
      ],
      "env": {
        "AUTH_SECRET": "YOUR_AUTH_SECRET_HERE",
        "DATABASE_URL": "YOUR_DATABASE_URL_HERE",
        "SQL_PROVIDER": "YOUR_SQL_PROVIDER_HERE",
        "RATARY_BASE_URL": "YOUR_RATARY_BASE_URL_HERE",
        "RATARY_API_KEY": "YOUR_RATARY_API_KEY_HERE"
      }
    }
  }
}

Cosmos MCP Configuration

mcpServers (Claude Desktop / Cursor)

{
  "mcpServers": {
    "teampolarity-cosmos-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@polarity-lab/cosmos-mcp"
      ],
      "env": {
        "COSMOS_TOKEN": "YOUR_COSMOS_TOKEN_HERE"
      }
    }
  }
}

Frequently Asked Questions

Ratary is categorized under Knowledge & Memory and uses a local stdio subprocess. In contrast, Cosmos MCP belongs to Knowledge & Memory using local stdio subprocess. Select Ratary when you need capabilities focused on knowledge & memory and Cosmos MCP when you require tools for knowledge & memory.

More alternatives to Ratary More alternatives to Cosmos MCP Knowledge & Memory category hub