- Skills (SKILL.md discovery, skill tool, /skills /skill) - plugin.json exec tools with permission prompts, timeouts and workspace trust (/plugins) - MCP stdio client: JSON-RPC initialize/tools/list/tools/call, mcp__server__tool, /mcp and sidebar status - task tool with general/explore/plan and .agent/agents/*.md roles, parallel read-only runs, cancel propagation, /agents - Keymap with Ctrl+X leader, keybinds.json overrides and /keys panel - Collapsed thinking, throttled streaming Markdown, leaner tool output, parallel read-only tools - Spawn: close-on-exec pipes and a process-wide fork lock - Tests for keymap, skills, plugins, MCP, sub-agents, shell compaction; docs/plugins.md