Support Claude Code subagent conversations

[sanggggg]

Problem

Currently, RetroChat assumes "1 conversation = 1 file" when importing Claude Code conversations. However, Claude Code stores subagent conversations (spawned via the Task tool) in separate files, breaking this assumption.

How Claude Stores Subagent Conversations

File Structure

~/.claude/projects/{project}/
├── {sessionId}.jsonl           # Main conversation
└── agent-{agentId}.jsonl       # Subagent conversations (separate files)

Linking Mechanism

Main conversation contains a Task tool invocation and result:

// Task tool invocation (in assistant message)
{
  "type": "tool_use",
  "name": "Task",
  "input": {
    "description": "Explore data model structure",
    "prompt": "...",
    "subagent_type": "Explore"
  }
}

// Tool result with agentId reference (in user message)
{
  "toolUseResult": {
    "status": "completed",
    "agentId": "aadaaea",           // Links to agent-aadaaea.jsonl
    "prompt": "...",
    "totalDurationMs": 63921,
    "totalToolUseCount": 26
  }
}

Agent file (agent-{agentId}.jsonl) contains:

{
  "sessionId": "20b86564-...",     // Same sessionId as parent!
  "agentId": "aadaaea",
  "isSidechain": true,             // Marks as subagent conversation
  "parentUuid": "...",             // Message chain within agent
  ...
}

Key Fields

Field	Location	Purpose
sessionId	Both files	Shared identifier grouping parent + agents
agentId	Agent file	Unique identifier (filename: agent-{agentId}.jsonl)
isSidechain	Agent file	Boolean flag marking messages as subagent context
toolUseResult.agentId	Parent file	Links to which agent file has the full conversation

Current Behavior

• agent-*.jsonl files are completely ignored during import
• Subagent conversations are lost
• The toolUseResult in the parent conversation contains only the final summary, not the full agent conversation

Proposed Solution

Schema Changes

ALTER TABLE chat_sessions ADD COLUMN parent_session_id TEXT 
    REFERENCES chat_sessions(id) ON DELETE CASCADE;
ALTER TABLE chat_sessions ADD COLUMN agent_id TEXT;
ALTER TABLE chat_sessions ADD COLUMN is_sidechain BOOLEAN DEFAULT FALSE;
ALTER TABLE chat_sessions ADD COLUMN spawn_tool_use_id TEXT;

Relationship Model

┌─────────────────────────────────────────────────────────┐
│ Main Session: 20b86564-d913-435b-ae5f-970dc6781821      │
│ file: 20b86564-....jsonl                                │
│                                                         │
│  msg1 → msg2 → [Task tool: spawn agent-aadaaea] → msg3  │
│                        │                                │
│                        ▼                                │
│         ┌─────────────────────────────────┐             │
│         │ Subagent Session: aadaaea       │             │
│         │ file: agent-aadaaea.jsonl       │             │
│         │ parent_session_id: 20b86564-... │             │
│         │ is_sidechain: true              │             │
│         │                                 │             │
│         │ agent_msg1 → agent_msg2 → ...   │             │
│         └─────────────────────────────────┘             │
└─────────────────────────────────────────────────────────┘

Implementation Tasks

• Update ClaudeCodeParser to detect and parse agent-*.jsonl files
• Add new fields to ChatSession model
• Create database migration for new schema
• Link agent sessions to parent sessions via toolUseResult.agentId
• Update TUI to display session hierarchy (collapsible subagents?)
• Update MCP server to expose subagent relationships
• Consider analytics implications (aggregate parent+children?)

Notes

The "1 conversation = 1 file" paradigm still holds in a sense - Claude treats subagents as separate conversations that share a session context. The sessionId is a grouping identifier, not a file identifier.