Codex CLI: Plugin System for Skills, MCP & App Connectors
CodexCodex CLI 0.110.0 introduces a plugin system that allows skills, MCP server entries, and app connectors to be loaded from the user's config or installed via a new app-server install endpoint backed by a local marketplace. This unifies what were previously three separate extension mechanisms into a single plugin lifecycle, enabling third-party skills and tools to be distributed and installed without manual file management. The release also removes legacy app-server v1 WebSocket and RPC interfaces, requiring integrations to migrate to the current v2 protocol.
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Codex CLI 0.110.0 Introduces a Unified Plugin System
Codex CLI 0.110.0, released March 5, 2026, ships the most architecturally significant extension point since the multi-agent system landed earlier in the year: a unified plugin system that consolidates how skills, MCP server entries, and app connectors are managed.
The Plugin System
Prior to 0.110.0, skills were authored and loaded via the filesystem, MCP servers were individually configured in ~/.codex/config.toml, and app connectors were handled separately. The new plugin system unifies these extension points under a single loading mechanism.
Plugins can be sourced in two ways:
- Config-based loading — plugins declared in the user's config file are loaded automatically when a session starts, consistent with how MCP servers were previously configured.
- Marketplace installation — a new install endpoint, exposed by the app server, enables plugins to be installed from a local marketplace. This means skills, MCP entries, and connectors can be packaged, distributed, and activated without manual file placement.
The local marketplace model is designed to scale: as the Codex ecosystem grows, third-party skill authors and MCP server publishers can package their work as installable plugins discoverable through the local interface.
Multi-Agent TUI Improvements
The multi-agent terminal interface receives several targeted improvements in 0.110.0:
- User approval prompts now surface directly within multi-agent flows, removing the need to break out of the current context to approve agent actions.
- Slash-command enablement allows agents in a session to be enabled or switched via slash commands.
- Ordinal-based agent nicknames (first, second, third...) make it easier to distinguish agents in complex parallel workflows.
- Role-labeled handoffs add context-aware labels when control passes between agents.
Windows Installer Script
A direct Windows installer script has been added to published release artifacts, completing cross-platform parity with the macOS and Linux scripts shipped in CLI 0.106.0.
Breaking Change: Legacy App-Server v1 Removed
The legacy app-server v1 WebSocket and RPC interfaces are removed in 0.110.0. Integrations built against v1 endpoints must migrate to the current v2 app-server protocol before upgrading.