Mimir

In Norse mythology, Mimir is the keeper of wisdom — the one the gods consult when they need to know what has come before.

Mimir is an MCP (Model Context Protocol) server that lets AI coding agents share session context with each other. It reads existing session files written by Claude Code, Codex CLI, and Gemini CLI, parses them into structured data, and exposes them as MCP tools.

No storage. No LLM calls. Just intelligent parsing of what your agents already write to disk.

Why

Claude Code, Codex, and Gemini work in isolation by default. Each session starts cold, with no knowledge of what the other agent did. Mimir bridges that gap — an agent can call list_sessions or get_session_summary to understand what happened in a prior session before picking up work.

Tools

list_sessions

List available sessions for a given project path and optional agent filter.

{
  "project_path": "/home/user/myproject",
  "agent": "claude-code"  // optional: "claude-code" | "codex" | "gemini"
}

get_session_summary

Parse a session file and return structured data about what happened — initial prompt, files modified, tool calls made, errors, and final state.

{
  "session_id": "abc123",
  "agent": "claude-code"
}

Session File Locations

Agent	Path
Claude Code	~/.claude/projects/<encoded-path>/<uuid>.jsonl
Codex	~/.codex/sessions/<YYYY>/<MM>/<DD>/rollout-<date>-<uuid>.jsonl
Gemini	~/.gemini/tmp/<project-alias>/chats/session-<date>-<uuid>.json

Installation

curl -fsSL https://raw.githubusercontent.com/iamngoni/mimir/master/install.sh | sh

Or if you have Rust installed:

cargo install --git https://github.com/iamngoni/mimir

MCP Configuration

Claude Code

claude mcp add mimir --transport stdio -- mimir

Or manually in ~/.claude.json:

{
  "mcpServers": {
    "mimir": {
      "type": "stdio",
      "command": "mimir",
      "args": []
    }
  }
}

Codex

codex mcp add mimir -- mimir

Or manually in ~/.codex/config.toml:

[mcp_servers.mimir]
command = "mimir"
args = []

Gemini CLI

Manually add to ~/.gemini/settings.json:

{
  "mcpServers": {
    "mimir": {
      "command": "mimir",
      "args": []
    }
  }
}

Tech Stack

• Rust + rmcp (MCP SDK)
• serde_json for JSONL/JSON parsing
• walkdir for session discovery
• stdio transport only

License

MIT