Codex Vault

Codex Vault is a local plugin for the Codex desktop app that can read Obsidian-compatible Markdown vaults, search notes, view backlinks and knowledge graphs, and add selected content to chat context.

[!IMPORTANT] The project is still in early development and is only tested through the personal marketplace; it has not been publicly released yet.

Features

• Browse and search Markdown, wikilinks, tags, and frontmatter.

• Display backlinks, orphan notes, broken links, and knowledge graphs.

• Select text and add it to the Codex composer as a note; it will not be sent automatically.

• Accumulate multiple notes, each retaining the note path, text, and line number.

• Read and write notes securely through MCP tools; writing is disabled by default.

Related MCP server: vault-master-mcp

Usage

After installation, create a new Codex task, select @Codex Vault, and enter "Open Vault Explorer". After the plugin is updated, you must use a new task; existing tasks will not hot-reload MCP tools.

To add a note:

1. Select text in the Markdown reader and click "Add to Chat".

2. Add any comments as needed, then click "Add to Chat" again.

3. Return to the composer and enter your question; the note will be sent to the model along with your input.

Notes only exist in the chat context and are not written back to the Markdown.

Capability Boundaries

• This is a Codex plugin and MCP app, not a fork of the Codex app.

• It cannot be installed as a fixed sidebar or model control menu in the Codex private UI.

• Notes use the public updateModelContext() API, not a private Codex note data model.

• It is currently mainly verified on macOS; other platforms have not been fully tested.

Development

Requirements: Node.js 22+, Yarn Classic 1.x, and a Codex app that supports Plugins/MCP Apps.

git clone https://github.com/Avery320/codex-vault.git
cd codex-vault
yarn install
yarn build
yarn workspace @foam/mcp test
yarn workspace @foam/graph-view test:unit

An environment with a personal marketplace configured can run:

codex plugin add codex-vault@personal
codex plugin list

Running ./scripts/launch_codex_vault_mcp directly only starts the stdio server and does not display the Codex UI. For the full update process, see the Development Guide.

Writing

Set CODEX_VAULT_ALLOW_WRITES=true, or make the content of ~/.config/codex-vault/allow-writes true, to enable writing tools.

To modify an existing note, you must first call preview_resource_update, then call update_resource with the returned SHA-256; if the file has changed, it will return conflict and will not overwrite the new content.

Documentation

• Usage Guide

• Architecture and Capability Boundaries

• Development Guide

• Security and Local Data

• Fork and License

Fork and License

Codex Vault is derived from Foam, inheriting its Markdown, wikilink, and graph core, and adding a Codex plugin, MCP app, multi-vault management, and chat notes.

This project is licensed under the MIT License. Upstream, Microsoft-derived source, and third-party dependencies are attributed in NOTICE.md. Codex Vault is not an official product of OpenAI, Obsidian, or Foam.