chore: Archive update-subagents-lesson change

openspec/changes/archive/2025-12-24-update-subagents-lesson/proposal.md

@@ -1,8 +1,14 @@
 # Proposal: update-subagents-lesson
 
-## Summary
+## Why
 
-Update the `04-subagents` lesson to align with the official Claude Code documentation at https://code.claude.com/docs/en/sub-agents. The current lesson is missing several key features and uses outdated configuration formats.
+The existing subagents lesson lacks critical features documented in the official docs and uses outdated configuration formats.
+
+## What Changes
+
+- Update README with all official features (built-in subagents, /agents command, CLI config, resumable agents)
+- Update example files to new YAML frontmatter format
+- Add new example subagents (debugger, data-scientist)
 
 ## Motivation
 

openspec/changes/archive/2025-12-24-update-subagents-lesson/specs/subagents-lesson/spec.md

@@ -1,6 +1,6 @@
 # Spec: Subagents Lesson Content
 
-## MODIFIED Requirements
+## ADDED Requirements
 
 ### Requirement: Configuration Format
 

openspec/specs/subagents-lesson/spec.md

@@ -0,0 +1,40 @@
+# subagents-lesson Specification
+
+## Purpose
+TBD - created by archiving change update-subagents-lesson. Update Purpose after archive.
+## Requirements
+### Requirement: Example Subagent - Debugger
+
+The lesson MUST include a debugger subagent example.
+
+#### Scenario: User needs debugging specialist
+- **Given**: A user wants a debugging-focused subagent
+- **When**: They view the examples
+- **Then**: They find a complete debugger.md example with root cause analysis approach
+
+### Requirement: Example Subagent - Data Scientist
+
+The lesson MUST include a data scientist subagent example.
+
+#### Scenario: User needs data analysis specialist
+- **Given**: A user wants a data analysis subagent
+- **When**: They view the examples
+- **Then**: They find a complete data-scientist.md example with SQL/BigQuery focus
+
+### Requirement: File Location Documentation
+
+The lesson MUST document where subagent files can be stored.
+
+#### Scenario: User learns storage locations
+- **Given**: A user wants to know where to put subagent files
+- **When**: They read the file locations section
+- **Then**: They learn about project (.claude/agents/), user (~/.claude/agents/), plugin, and CLI locations with priority order
+
+### Requirement: Proactive Invocation Guidance
+
+The lesson MUST explain how to encourage automatic subagent use.
+
+#### Scenario: User wants subagent used automatically
+- **Given**: A user wants Claude to proactively use their subagent
+- **When**: They read the usage section
+- **Then**: They learn to include "use PROACTIVELY" or "MUST BE USED" in the description field