Claude Code extension component architecture

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This entry sits under AI Agent payment protocols overview · a 7-protocol survey. Read it with ERC-7715 overview · Wallet Permissions and AI Agent auto-payment for adjacent context and AP2 · Google Agent Payments Protocol overview for the broader system boundary.

[!info] TL;DR Source: 5 architecture diagrams received from 2026-04-16 (the WeChat official account “童童的 AI 创业圈”). The following is the full textualization of the image content.

1. The 6 extension components

Claude Code’s Agentic Loop (Plan → Act → Observe → Reflect) acquires capabilities through 6 types of extension components.

Component	Role	Use case	Example
CLAUDE.md	Holds persistent context, auto-loaded every session	Project Specs (project conventions, global rules)	Use pnpm; test before commit
Skills	Reusable capability modules (knowledge, instructions, workflows), loaded on demand	Reference Docs / Standard Tasks	”/deploy to run deployment”
Subagent	An independent sub-Agent. Runs in an isolated context and returns a result summary	Context Isolation / Parallel Tasks	Parse a file and return a conclusion
Agent Teams	Multiple Agents collaborate, sharing a task list and communicating with each other	Parallel Research / Complex Dev	Launch multiple reviewers
MCP	Connects to external systems and tools, accessing external data/actions	External Data / Actions	DB query; Slack send
Hook	An automation script outside the loop. Triggered on specific events	Deterministic Automation	Run ESLint after changes

2. Distinctions between components

Skills vs Subagent

Aspect	Skills	Subagent
Essence	Reusable knowledge or flow	Independent execution unit
Core value	Reuse content across different tasks	Context isolation
Fitting scenario	Reference material, standard flows	Large-scale code analysis or parallel tasks

CLAUDE.md vs Skills

Aspect	CLAUDE.md	Skills
Loading method	Auto-loaded every session	Loaded on demand
File reference	Supports @path	Supports @path
Can trigger a flow	No	Yes
Best use	Global rules	Reusable flows

MCP vs Skill

Aspect	MCP	Skills
Essence	External-system connection protocol	Knowledge or flow
Capability provided	Tool interface and data access	Usage and business logic
Example	Slack, DB	Code-review flow

They are usually combined: MCP provides the connection, Skills define the usage.

3. Plugins & Marketplace

Components can be packaged as a Plugin for distribution.

Plugin
  ├── Skills
  ├── Hooks
  ├── Subagents
  └── MCP Servers
         ↓
    Marketplace (package and distribute extension features)

Skills use namespaces (e.g. /my-plugin:review) to avoid collisions.

4. Component hierarchy and merge rules

Components stack in 4 layers (additive):

User level
  ↓
Project level
  ↓
Plugin level
  ↓
Managed policy level

The CLAUDE.md files of all layers are loaded and merged into the conversation context. Conflict resolution: more specific rules take precedence.

Combination usage examples

Combination	Behavior	Example
Skills + MCP	MCP provides the connection, Skills define the usage	Skills describe the DB schema
Skills + Subagent	Skills launch multiple Subagents	/audit checks security and performance simultaneously
CLAUDE.md + Skills	Global rules + on-demand knowledge	CLAUDE.md defines the API conventions
Hook + MCP	Hook calls an external system	Notify Slack after a critical file change

5. Context cost

Each extension component consumes the model’s context window.

Component	Load timing	Loaded content	Context cost
CLAUDE.md	At session start	All content	Every request (high)
Skills	At session start + on invocation	Description + all content	Relatively low
MCP Servers	At session start	Tool definitions	Every request (high)
Subagents	At creation	Independent context	Isolated from the main session
Hooks	On trigger	None by default	Zero

A balance between capability and cost is required. Tips: set disable-model-invocation: true and the Skill is loaded only on manual invocation, with zero cost.

Potential connection to the agent payment layer (under consideration)

The following are early-stage associations, subjects for future consideration.

Provide payment capability as an MCP Server: any Agent calls Agent Payment Infrastructure Research Report via the MCP protocol (check_balance, authorize_payment, get_price, dispute). The lower layer depends on ERC-4337 Overview · Application-Layer Implementation of Account Abstraction
Monetizing the Marketplace: after becoming Skill marketplace monetization, it can be used as the backend for billing/payment (for the choice of payment currency, see USD Stablecoin Interchange Market)
Tiered budget management: user level → project level → Agent level → task level → single invocation, mapped to the component hierarchy
Financial cost tracking: similar to context-cost tracking, track the financial cost of each Skill invocation (how much was spent, whether it is worth it)

These directions are unconfirmed, recorded only.

Textualization compiled · 2026-04-16

Wiki Index
Agent Payment Infrastructure Research Report
Skill marketplace monetization