feat(copilot): subagents

[Sg312]

Summary

Adds subagents to the copilot.
Also adds components to see copilot plan, edit diffs in chat, and options.
Adds nicer thinking text
Makes diff view accept/reject optimistic
Fixes chat load on refresh

Type of Change

• New feature
• Bug fix

Testing

Manual with @emir-karabeg

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Review	Updated (UTC)
docs	Skipped		Jan 10, 2026 7:32pm

[greptile-apps]

Greptile Overview

Greptile Summary

Implemented comprehensive subagent architecture for the Copilot feature, enabling nested agent execution with streaming content and tool calls displayed within parent tool calls.

Key Changes

• Subagent Streaming Infrastructure: Added complete SSE handling for subagent events (subagent_start, subagent_end, and subagent-scoped content/tool_call/tool_result events) in the Copilot store
• New Subagent Tools: Created 12 new auto-executing client tools (debug, plan, edit, test, research, auth, deploy, knowledge, custom_tool, tour, info, workflow) that spawn server-side subagents
• UI Components: Enhanced tool-call component with nested subagent content rendering including thinking blocks, tool calls, plan steps, and interactive option selectors with keyboard navigation
• Message Queue: Implemented Cursor-style message queuing that allows users to queue messages while another is streaming, with send now/remove controls
• Trigger Mode Support: Extended get_block_config tool to support trigger mode configuration retrieval for blocks with trigger capabilities
• Context Usage Removal: Removed deprecated context-usage feature and related components/API endpoints
• Manage Custom Tool Enhancement: Added list operation to manage_custom_tool and improved conditional interrupt handling

Architecture

The subagent system works through a parent-child relationship where specialized tools like debug or plan spawn server-side subagents that stream their reasoning and tool calls back to the client. These are displayed as nested, collapsible content within the parent tool call, providing transparency into the subagent's work.

Testing Focus

• Verify subagent streaming works correctly for all 12 new tools
• Test message queuing with multiple queued messages
• Validate nested tool call execution and state management
• Check trigger mode configuration retrieval for trigger-enabled blocks
• Test option selector keyboard navigation (arrow keys, enter) on the last message only

Confidence Score: 4/5

• Safe to merge with careful testing - comprehensive feature implementation with well-structured code
• Large PR with significant architectural changes (+2552/-664 lines). The subagent streaming logic is complex but well-structured with proper error handling and logging. Code follows project patterns and TypeScript conventions. Main concerns are the complexity of the streaming state management and the need for thorough testing of edge cases in nested subagent execution. No critical bugs found, but the scale and complexity warrant extensive QA.
• Pay close attention to apps/sim/stores/panel/copilot/store.ts - complex streaming logic with subagent state management needs thorough testing

Important Files Changed

File Analysis

Filename	Score	Overview
apps/sim/stores/panel/copilot/types.ts	5/5	Added subagent type definitions including SubAgentContentBlock, subagent properties on CopilotToolCall, and QueuedMessage interface for message queuing feature
apps/sim/stores/panel/copilot/store.ts	4/5	Implemented comprehensive subagent streaming logic with SSE handlers, added message queue functionality, removed context-usage feature, added new tool instantiators for subagent tools
apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/components/tool-call/tool-call.tsx	4/5	Added comprehensive subagent content rendering with PlanSteps, OptionsSelector, and SubAgentContent components for displaying nested tool calls and thinking blocks
apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/components/queued-messages/queued-messages.tsx	5/5	New component implementing Cursor-style message queuing UI with expand/collapse, send now, and remove functionality
apps/sim/lib/copilot/tools/client/other/debug.ts	5/5	New subagent tool for debugging, auto-executes with server-side subagent handling nested content stream
apps/sim/lib/copilot/tools/server/blocks/get-block-config.ts	4/5	Implemented trigger mode support with trigger inputs/outputs extraction and validation, fixed option resolution to prefer id over label
apps/sim/lib/copilot/registry.ts	5/5	Extended schemas with trigger parameter for get_block_config and list operation for manage_custom_tool, added triggerMode to output schemas
apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/copilot.tsx	5/5	Added QueuedMessages component, removed context-usage functionality, enabled message submission during active streaming for queuing

Sequence Diagram

sequenceDiagram
    participant User
    participant UI as Copilot UI
    participant Store as CopilotStore
    participant API as Server API
    participant SubAgent as Subagent (debug/plan/edit/etc)

    User->>UI: Sends message
    UI->>Store: sendMessage()
    Store->>API: POST /api/copilot/chat (stream)
    
    Note over API,SubAgent: Main agent processes request
    API-->>Store: SSE: content (main agent text)
    Store-->>UI: Update message content
    
    API-->>Store: SSE: tool_call (e.g., debug tool)
    Store->>Store: Create tool call with pending state
    Store->>Store: Execute client tool (debug.execute())
    Store-->>UI: Show tool call in UI
    
    Note over API,SubAgent: Server invokes subagent
    API-->>Store: SSE: subagent_start {tool_call_id}
    Store->>Store: Set subAgentParentToolCallId
    Store->>Store: Mark parent tool as subAgentStreaming=true
    
    loop Subagent streaming
        API-->>Store: SSE: {subagent: "debug", type: "content"}
        Store->>Store: Append to subAgentContent[toolCallId]
        Store->>Store: Update subAgentBlocks with text block
        Store-->>UI: Update nested content in tool call
        
        API-->>Store: SSE: {subagent: "debug", type: "tool_call"}
        Store->>Store: Add to subAgentToolCalls[toolCallId]
        Store->>Store: Update subAgentBlocks with tool block
        Store->>Store: Execute nested tool if no interrupt
        Store-->>UI: Show nested tool in subagent section
        
        API-->>Store: SSE: {subagent: "debug", type: "tool_result"}
        Store->>Store: Update nested tool state to success/error
        Store-->>UI: Update nested tool status
    end
    
    API-->>Store: SSE: subagent_end
    Store->>Store: Set subAgentStreaming=false
    Store->>Store: Clear subAgentParentToolCallId
    Store-->>UI: Finalize subagent display
    
    API-->>Store: SSE: tool_result {toolCallId, success}
    Store->>Store: Update parent tool state to success
    Store-->>UI: Show parent tool completed
    
    API-->>Store: SSE: done
    Store->>Store: Complete streaming
    Store-->>UI: Enable input

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