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mcp/harbor
Grok

postbag for Grok

io.github.parasxos/postbag

Local Claude Code and Codex sessions on one machine exchange letters through native inputs.

client:Grok transport:stdio runtime:pypi

Install postbag in Grok

.mcp.json (in your project root)

Held in this page only — never stored, logged, or sent anywhere but back to your screen. 

{
  "mcpServers": {
    "postbag": {
      "type": "stdio",
      "command": "uvx",
      "args": [
        "postbag"
      ],
      "env": {
        "POSTBAG_CODEX": "<POSTBAG_CODEX>"
      }
    }
  }
}

Grok Build reads Claude Code's .mcp.json and Claude Desktop's config unchanged, so a server you have already set up there needs nothing new. The Grok web app and X integration do not take custom servers. Grok docs

postbag in other clients

postbag MCP server