OpenCode vs Claude Code Hooks Comparison

opencode-hooks.md

OpenCode Hooks: A Comparison with Claude Code

OpenCode supports a hooks feature similar to Claude Code, but with a plugin-based architecture that offers more flexibility and programmability.

Overview

Feature	Claude Code	OpenCode
Primary approach	Config-based shell commands	Plugin-based TypeScript/JS
Hook execution	Bash scripts via JSON config	Full SDK access in plugins
Config hooks	Main feature	Experimental feature

OpenCode's Plugin-Based Hooks

OpenCode uses a plugin architecture for hooks defined in TypeScript/JavaScript. Plugins have access to the full SDK client and context.

Available Hooks

Hook	Description
event	Subscribe to events (file changes, session events, etc.)
config	Modify configuration
tool	Define custom tools
auth	Custom authentication
chat.message	Intercept chat messages
chat.params	Modify chat parameters
permission.ask	Handle permission requests
tool.execute.before	Run before tool execution
tool.execute.after	Run after tool execution
experimental.chat.messages.transform	Transform messages
experimental.chat.system.transform	Transform system prompts
experimental.session.compacting	Handle session compaction

Available Events

OpenCode provides a rich event system that plugins can subscribe to:

• File Events: file.edited, file.watcher.updated
• Session Events: session.created, session.compacted, session.deleted, session.idle, session.status, session.updated
• Message Events: message.part.removed, message.part.updated, message.removed, message.updated
• Tool Events: tool.execute.after, tool.execute.before
• Permission Events: permission.replied, permission.updated
• LSP Events: lsp.client.diagnostics, lsp.updated
• Command Events: command.executed

Plugin Locations

• Project plugins: .opencode/plugin/
• Global plugins: ~/.config/opencode/plugin/
• npm plugins: Configured in opencode.json via plugin array

Experimental Config-Based Hooks

OpenCode also has experimental config-based hooks in opencode.json that are more similar to Claude Code's approach:

{
  "experimental": {
    "hook": {
      "file_edited": {
        "*.ts": [
          {
            "command": ["prettier", "--write"],
            "environment": { "NODE_ENV": "development" }
          }
        ]
      },
      "session_completed": [
        {
          "command": ["notify-send", "Session completed!"]
        }
      ]
    }
  }
}

Supported Config Hooks

• file_edited - Run commands when files matching a pattern are edited
• session_completed - Run commands when a session completes

Example Plugin Hook

Here's an example of a plugin that protects .env files from being read:

import type { Plugin } from "@anthropic-ai/opencode-plugin"

export default {
  "tool.execute.before": async (input, output) => {
    if (input.call.name === "Read" && input.call.input.file_path?.includes(".env")) {
      output.abort = "Cannot read .env files for security reasons"
    }
  }
} satisfies Plugin["hooks"]

Key Differences

Claude Code Hooks

• Configured in JSON settings files
• Execute shell commands
• Events: PreToolUse, PostToolUse, Stop, SubagentStop, Notification, UserPromptSubmit, PreCompact, SessionStart, SessionEnd
• Hooks receive JSON input via stdin and return exit codes or JSON output

OpenCode Hooks

• Plugin-based with TypeScript/JavaScript
• Full programmatic access to SDK and context
• More experimental hooks for transforming messages and system prompts
• Config-based hooks are experimental and limited to file_edited and session_completed

Resources

• OpenCode Plugins Documentation
• Claude Code Hooks Reference