Learn Claude Code

Learning Path

s01 to s17: Progressive Agent Harness Design

Layer Legend

Tools & Execution
Planning & Control
Memory Management
Concurrency & Scheduling
Multi-Agent Platform
01
s01Minimal model/tool loop

The Agent LoopOne Loop Is All You Need

106 lines of code1 tools

The smallest useful agent is a loop that calls the model, runs tools, and feeds results back.

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02
s02Tool dispatch map

Tool UseAdd a Tool, Add Just One Line

149 lines of code5 tools

The loop stays stable while capabilities register into a dispatch table.

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03
s03Permission gate

PermissionCheck Permissions Before Execution

192 lines of code5 tools

Dangerous actions need a harness decision point before the shell runs.

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04
s04Lifecycle hooks

HooksHang on the Loop, Don't Write into It

215 lines of code5 tools

Cross-cutting behavior belongs around the loop, not tangled inside it.

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05
s05Todo manager

TodoWriteAn Agent Without a Plan Drifts Off Course

291 lines of code6 tools

Explicit plans keep long-running work visible and correctable.

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06
s06Isolated subtask context

SubagentBreak Large Tasks into Small Ones with Clean Context

298 lines of code6 tools

Subagents give each subtask a clean message history while preserving the main thread.

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07
s07On-demand skill loader

Skill LoadingLoad Only When Needed

313 lines of code6 tools

Inject specialized knowledge only when the task actually needs it.

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08
s08Context compaction

Context CompactContext Will Fill Up

510 lines of code5 tools

Compression keeps the conversation usable when the context window gets crowded.

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09
s09Durable memory layer

MemoryKeep a Layer That Doesn't Lose Details

686 lines of code5 tools

Some facts should survive summarization and future sessions.

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10
s10Task board

Task SystemBreak Big Goals into Small Tasks

473 lines of code11 tools

A task graph turns vague goals into ordered, observable work.

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11
s11Background execution

Background TasksSlow Operations Go to the Background

412 lines of code5 tools

The agent can keep reasoning while slow work completes elsewhere.

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12
s12Scheduled task creation

Cron SchedulerProducing Work on a Schedule

650 lines of code5 tools

Recurring work should be created by the harness, not remembered by the model.

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13
s13Team runtime with task-bound worktrees

Agent Team RuntimePersistent Teammates, Atomic Claims, Task-Bound Worktrees

1599 lines of code5 tools

Persistent teammates can reliably discover and execute parallel work when the runtime owns messaging, atomic claims, and task-bound working directories.

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14
s14MCP tool bridge

MCP ToolsExternal Tools, Standard Protocol

451 lines of code5 tools

External services can become agent tools through a standard discovery and call protocol.

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15
s15Integrated harness

Integrated HarnessMany Mechanisms, One Loop

2770 lines of code26 tools

The integrated harness is still one loop, surrounded by the systems introduced across the course.

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16
s16Resumable workflow runtime

Workflow RuntimeScripts Own Fixed Orchestration

725 lines of code27 tools

When orchestration has a fixed shape, code can make it parallel, deterministic, and resumable.

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17
s17Goal completion gate

Goal LoopIndependent Evaluation Decides When to Stop

802 lines of code5 tools

A durable goal keeps the loop working until an independent evaluator finds the completion condition satisfied in the conversation.

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LOC Growth

s01
106
s02
149
s03
192
s04
215
s05
291
s06
298
s07
313
s08
510
s09
686
s10
473
s11
412
s12
650
s13
1599
s14
451
s15
2770
s16
725
s17
802