{"version":"2.1.300","anchor":"plugin-install-and-mcp-startup-reworked-in-headless-mode","canonical_anchor":"plugin-install-and-mcp-startup-reworked-in-headless-mode","heading":"Plugin install and startup reworked in non-interactive sessions","tier":"notice","area":"Headless Mode","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.300\/e\/plugin-install-and-mcp-startup-reworked-in-headless-mode","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.300","markdown":"### Plugin install and startup reworked in non-interactive sessions\n\nIn non-interactive sessions, plugin install now settles before session-start hooks run again, and CLAUDE_CODE_SYNC_PLUGIN_INSTALL waits for pending installs\n\n**Unclear.** Exactly how startup timing changes for a headless session is not clear.\n\n**What**\n\nClaude Code can run without a chat window, for example from a script. These are called headless or print sessions. The way they install plugins and start MCP servers at startup has been reworked. Plugins are add-ons, and MCP servers are outside programs that provide tools.\n\n- With `CLAUDE_CODE_SYNC_PLUGIN_INSTALL` set, startup waits for a plugin install that is still in progress.\n\n- Session-start hooks run again once plugin install has finished. Hooks are your own commands that Claude Code runs at set moments.\n\n- Startup can also refresh plugin marketplaces, the catalogs plugins come from.\n\n**Why**\n\nThis changes when hooks and skills that come from plugins become available in headless and print sessions.\n\n- Area: Headless Mode\n- Tier: You'll notice\n- Useful: 3\/5\n- Signal: 2\/5\n- Scope: individual\n- Heads-up: no"}