Feature Request: Add session_start hook for session lifecycle #12110

Summary

Request to add a session_start hook to complement the existing session_completed hook, enabling actions to be triggered when a new session begins.

Use Case

I'm using a Continuous Learning MCP Server that stores user preferences and learned patterns across sessions. Currently:

• ✅ session_completed hook exists - can save state when session ends
• ❌ session_start hook missing - cannot auto-load state when session begins

This means the MCP can save memories, but there's no way to automatically read them at the start of a new session. Users must manually trigger the read operation.

Proposed Solution

Add session_start to the experimental hooks:

// Current (from opencode-sdk-go/config.go)
type ConfigExperimentalHook struct {
    FileEdited       map[string][]ConfigExperimentalHookFileEdited `json:"file_edited"`
    SessionCompleted []ConfigExperimentalHookSessionCompleted      `json:"session_completed"`
}

// Proposed
type ConfigExperimentalHook struct {
    FileEdited       map[string][]ConfigExperimentalHookFileEdited `json:"file_edited"`
    SessionCompleted []ConfigExperimentalHookSessionCompleted      `json:"session_completed"`
    SessionStart     []ConfigExperimentalHookSessionStart          `json:"session_start"` // NEW
}

Example Configuration

{
  "experimental": {
    "hooks": {
      "session_start": [
        {
          "command": ["node", "scripts/load-context.js"]
        }
      ]
    }
  }
}

Reference

Claude Code supports SessionStart hooks which enables this workflow. See: everything-claude-code hooks.json

Impact

This would enable:

1. Auto-loading user preferences/context at session start
2. Persistent memory across sessions
3. Better integration with learning/memory MCP servers
4. Parity with Claude Code's hook capabilities

Thank you for considering this feature!