Claude Code Agent System Architecture

Layer 1 — User Interaction

CLI Interface

Command Line

VSCode Extension

Editor Plugin

Web Interface

Browser Access

↓

Layer 2 — Agent Core Scheduling

Main Loop

Task Scheduling
State Management
Exception Handling

Message Queues

Async Communication
Stream Processing
Back-pressure Control

Session Stream

Real-time Response
Streaming Output

Message Compressor

Intelligent Compression
Context Optimization

↓

Layer 3 — Tool Execution & Management

Tool Engine

Discovery
Validation
Scheduling

Concurrency Control

Load Balancing
Resource Mgmt

SubAgent Mgmt

Task Isolation
Error Recovery

Permission Gateway

Security Audit
Access Control

Tool Ecosystem

File Ops

Read / Write / Edit

Search

Glob / Grep

Task Mgmt

Todo / Status

System

Bash Execution

Network

Fetch / Search

Planning

Plan Mode

MCP

Protocol Support

Dev Tools

Diagnostics

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Layer 4 — Storage & Persistence

Short-term Memory

Active Messages

Compressed History

Medium-term Context

Persistent Storage

CLAUDE.md Files

State Cache

Fast Retrieval