What problem does it solve? Extending a coding-agent harness normally requires recompiling the core or wiring up an MCP server. This Skill documents the Catalyst Code plugin system so you can add hooks, custom tools, slash commands, OAuth providers, and memory backends by dropping files into .catalyst-code/plugins/. ## Core Features & Use Cases - Hook authoring: Write pre/post hook scripts (pre_bash, pre_write, pre_tool, post_tool, lifecycle hooks) that receive JSON on stdin and return allow/modify/notify responses on stdout, with policy-table failure semantics. - Custom tools and commands: Declare model-callable tools with JSON Schema parameters, override built-in tools, disable tools, and create script-backed or prompt-backed slash commands. - Provider and memory integration: Add subscription OAuth providers (login/complete/token/clear actions) and replace the markdown memory store with an external memory_provider backend. - Use Case: You want every file write linted before it lands. Create a plugin with a pre_write hook script, register it in plugin.json, install it with /plugin-install, and the hook can block or rewrite content before the write executes. ## Quick Start Use the plugin-authoring skill to create a Catalyst Code plugin with a pre_write hook that blocks writes to files containing secrets.
