Claude–Codex Session Link

Claude–Codex Session Link is an open-source MCP server published by Dayc-l under the MIT License. It lets OpenAI Codex find and read locally saved Claude Code conversations, synchronize new messages before Codex replies, and optionally send text-only follow-up questions to Claude. It was previously named Claude Session Link.

What It Is

The project is a stdio MCP / JSON-RPC server and CLI that connects two coding assistants. It reads Claude Code conversation files saved on the same machine (terminal and VS Code sessions) so that Codex can use that history without the user copying and pasting it between windows. It reads Claude Code history, not claude.ai web conversations.

How the workflow runs

The server exposes four tools: claude_sessions lists and searches local conversations, claude_read_session reads a selected one along its current parent chain, claude_session_updates returns new or revised context using a cursor, and claude_ask_session previews or sends a follow-up question. Once a session is selected, Codex is instructed to call the updates tool after each user message and before replying. The cursor handles pagination, branch changes, compaction, and revisions to earlier messages. Search matches metadata such as titles, first-question previews, session IDs and project paths rather than full text. Thinking blocks, image payloads and tool input/output bodies are excluded from reads.

Follow-up questions to Claude

Follow-ups are previewed by default. Sending requires an explicit flag and invokes the Claude CLI with tools, hooks and MCP disabled. The default fork mode creates a new session branch, while resume appends to an existing one after the user confirms it is idle. Sending uses the network and consumes Claude usage.

Setup path

It requires Node.js 22 or newer and needs no npm install. Users clone the repository, run the CLI, and add an MCP entry to the project's Codex config.toml; a PowerShell helper can preview or apply that configuration. The README states the reader has been validated on Windows. Synchronization depends on the host following the MCP instructions and is triggered before replies rather than by a background watcher. The README reports 21 offline tests passing, and notes that real authenticated network follow-ups have not been verified end to end.