Claude extension landscape

Formative, not a validated control catalogue. Star counts are unaudited survey integers. If the survey left a hole, this page says unverified. It does not guess a URL, a date, or a star count.

flowchart TB
  products["Products"]
  surfaces["Official extension surfaces"]
  packs["Community packs via those surfaces"]
  routers["Routers under the client, not Anthropic"]
  products -->|"clients"| surfaces
  surfaces -->|"install through"| packs
  products -->|"may sit under"| routers

How the layers stack. The lower edge is optional: a router may sit under the official client. It is not a required hop, and it is not an Anthropic product.

1. Read the five handoffs2. Scan the layer board3. Open the category4. Check gaps before a star count or a proxy repo

Five handoff points

DEC-01

Mod is a layer, not the whole plugin

Mod is official Claude Code term v2.1.287+: in-process JS/TS, can redraw UI and rewrite tool calls, unsandboxed. Settings hooks, skills, and MCP are different layers. A plugin can contain all of them.

DEC-02

Distribution is marketplaces

Distribution is marketplaces. Official claude-plugins-official auto-added. Community @claude-community. Author repos unreviewed. claude.ai has a separate directory that syncs into Claude Code.

DEC-03

Skills file is not the Skills API

Skills are the portable instruction pack. API version needs code execution, is workspace-scoped, different install path from a Claude Code skill file.

DEC-04

CLAUDE.md does not enforce

CLAUDE.md does not enforce. Hooks and mods do. Orgs can shut user mods off with disableAllHooks or allowManagedModsOnly while leaving skills and MCP loaded.

DEC-05

A router README is not the protocol

Model routing is the largest community fork and breaks when Claude Code request shape changes. Anthropic gateway is the supported version. Do not treat a router README as the Claude Code protocol.

DEC-05 is quoted as written. It is not a measured fork ranking. See GAP-18.

flowchart TB
  subgraph userLane["User lane"]
    choose["Choose marketplace or author repo"]
  end
  subgraph ccLane["Claude Code lane"]
    bundle["Plugin loads its parts"]
  end
  subgraph modelLane["Model lane"]
    gate["Anthropic gateway supported"]
    fork["Community router not Anthropic"]
  end
  choose --> bundle
  bundle --> gate
  bundle --> fork

Three lanes. The two model-lane nodes are alternatives, not a single turn that calls both.

Layers, side by side

Products ✓

claude.ai chat
Cowork
Claude Desktop, including the Code tab (Linux is beta)
Claude Code in the terminal
VS Code
JetBrains
Cloud
Mobile Remote Control
Claude API

Extension surfaces ✓

CLAUDE.md and path-scoped rules
Output styles
Agent Skills
Settings hooks
MCP (remote connectors and local servers)
Desktop .mcpb bundles
Claude Code plugins and marketplaces
Claude Agent SDK
Skills API
Mods (plugins can ship them from v2.1.287)

A plugin can contain ✓

Skills (namespaced /plugin:skill)
Agents
Hooks
MCP
LSP
Monitors
bin/ on PATH (v2.1.91, week of 30 March–3 April 2026)
Settings
Mods

Under the client ✓

Community routers sit under the official client and rewrite the model endpoint
They are not Anthropic products
Supported path: Anthropic gateway
musistudio/claude-code-router is one named router, not the protocol

Membership is the columns. The diagram above is only the order of the lanes. Linux beta is a Desktop note from the survey, not a separate product.

flowchart TB
  official["claude-plugins-official auto-added"]
  community["Community @claude-community"]
  demo["Demo marketplace in claude-code"]
  authors["Author repos unreviewed"]
  web["claude.ai directory syncs in"]
  cc["Claude Code"]
  official --> cc
  community --> cc
  demo --> cc
  authors --> cc
  web --> cc

Where a pack can come from. The community GitHub page was not fetched; @claude-community is the handoff name.

Category cards

C-MOD · L-MOD

Mods

Official term, Claude Code v2.1.287+. In-process JS/TS. Can redraw UI and rewrite tool calls. Not sandboxed.

Drawing: terminal and Desktop Code tab. Not VS Code chat, claude -p, or cloud.

✓ SRC-001 · ship week ?? GAP-09

C-PLUGIN · L-PLUGIN

Plugins

A bundle: skills, agents, hooks, MCP, LSP, monitors, bin/ on PATH, settings, mods. Skills namespaced /plugin:skill.

✓ official marketplace auto-added · list ?? GAP-02

C-SKILL · L-SKILL

Skills

SKILL.md folder, staged load. API is a different path: POST /v1/skills, up to 20, needs code_execution_20250825, workspace-scoped.

✓ SRC-009 · SRC-011

C-HOOK · L-HOOK

Hooks

Shell, HTTP, prompt, agent, or MCP-tool. Named events include PreToolUse, PostToolUse, Stop, PermissionDenied, InstructionsLoaded.

~ full event list not copied · SRC-017

C-MCP · L-MCP

MCP

Product-wide connectors directory (Verified vs Community). Desktop bundles are .mcpb (was .dxt).

✓ SRC-020 · rename ~ SRC-024

C-SDK · L-SDK

Agent SDK

Old name Claude Code SDK. Custom tools and plugins have docs. TS SDK V2 session API is marked removed.

npm names ?? GAP-11 · toolset id ?? GAP-10

C-ROUTE · L-ROUTE

Routers

Sit under the official client and rewrite the model endpoint. Not Anthropic products. Supported path is the Anthropic gateway.

✓ SRC-029 · SRC-030 · stars ~

flowchart LR
  author["Author"]
  admin["Org admin"]
  user["Claude Code user"]
  ship["Ship a mod in a plugin"]
  lock["Leave skills and MCP, block user mods"]
  install["Install from a marketplace"]
  surfaces["Extension surfaces"]
  author --> ship
  ship --> surfaces
  admin --> lock
  lock --> surfaces
  user --> install
  install --> surfaces

Documented roles only. Not a studied user cohort, and not a personal stack.

flowchart LR
  md["CLAUDE.md is advisory"]
  hook["Hook can enforce"]
  mod["Mod can enforce"]
  org["Org can shut user mods off"]
  gap["Enforcement is not the file"]
  md --> gap
  hook --> gap
  mod --> gap
  org --> gap

CLAUDE.md is advisory. A hook or a mod enforces. An org can still shut user mods off.

flowchart TB
  cc["Claude Code"]
  gate["Anthropic gateway"]
  model["Model endpoint"]
  cc -->|"supported path"| gate
  gate --> model

Supported model path. Anthropic gateway. Not a community router.

flowchart TB
  cc["Claude Code"]
  router["Community router"]
  model["Rewritten model endpoint"]
  cc -->|"not an Anthropic product"| router
  router --> model

Community path. The router rewrites the endpoint. Not an Anthropic product. Not the protocol.

sequenceDiagram
  participant User
  participant Market as Marketplace
  participant Plugin
  participant Skill
  participant Hook
  participant Mod
  User->>Market: Install
  Market->>Plugin: Bundle
  Plugin->>Skill: /plugin:skill
  Plugin->>Hook: Settings hooks
  Plugin->>Mod: In-process handlers

Install sequence. MCP, LSP, monitors, bin/ on PATH, and settings are also in a plugin and are not drawn (six-participant cap).

Baseline, useful, fail

Card	What to use it for
User story	Author ships a mod in a plugin. User installs from a marketplace. Org admin can block user mods and still leave skills and MCP loaded. Roles from the survey, not a studied cohort.
Baseline	Official clients and their extension surfaces. No personal stack was in the survey. A router is under that baseline, not inside it.
Useful	Terminal and Desktop Code tab: a mod can redraw UI and rewrite tool calls, prompts, and the named UI pieces.
Fail	No drawing in VS Code chat, claude -p, or cloud. Not sandboxed. Function-hooks env var ignored from v2.1.287. Router breaks when the request shape changes.

flowchart LR
  mod["In-process mod"]
  termOk["Terminal drawing works"]
  deskOk["Desktop Code tab drawing works"]
  vscNo["VS Code chat no drawing"]
  pipeNo["claude -p no drawing"]
  cloudNo["Cloud no drawing"]
  mod --> termOk
  mod --> deskOk
  mod --> vscNo
  mod --> pipeNo
  mod --> cloudNo

Where mod drawing works from v2.1.287. Three clients on the right are explicitly out.

stateDiagram-v2
  state "User mods" as userMods
  state "disableAllHooks" as blocked
  state "allowManagedModsOnly" as managed
  state "safe-mode flag" as safeMode
  state "Skills and MCP stay loaded" as skillsStay
  [*] --> userMods
  userMods --> blocked
  userMods --> managed
  userMods --> safeMode
  blocked --> skillsStay
  managed --> skillsStay

Org controls. Only disableAllHooks and allowManagedModsOnly are shown leaving skills and MCP loaded. The survey does not say that about the safe-mode flag.

User story

An author ships an in-process mod inside a plugin. Drawing is for the terminal and the Desktop Code tab.

Baseline

Hooks, skills, and MCP stay different layers. A plugin can contain all of them, including the mod.

Useful

Watch, rewrite, or take over tool calls, prompts, and UI: panes, the band above the prompt, the spinner, tool rows.

Fail

Not sandboxed. No drawing in VS Code chat, claude -p, or cloud. CLAUDE_CODE_ENABLE_FUNCTION_HOOKS is ignored from v2.1.287.

Built-ins

Name	Note	Badge
cc-plugin-diff	Built-in	✓
cc-plugin-agents-md	Built-in	✓
cc-plugin-telemetry	Built-in	✓
cc-plugin-sec-default	Built-in	✓
cc-plugin-you-should-know	Built-in, off by default	✓

Samples

Name	Note	Badge
token-weather	Named sample. Repo URL not fetched.	??
blast-radius	Named sample. Repo URL not fetched.	??
replay-theater	Named sample. Repo URL not fetched.	??

Sample repo URL: unverified (GAP-05). ??

flowchart TB
  file["SKILL.md folder staged load"]
  api["POST /v1/skills"]
  cc["Claude Code skill file"]
  ws["Workspace-scoped API skill"]
  exec["Needs code_execution_20250825"]
  file --> cc
  api --> ws
  api --> exec

Two install paths. Code execution is a requirement of the API path, not a third product.

flowchart LR
  kinds["shell HTTP prompt agent MCP-tool"]
  pre["PreToolUse"]
  post["PostToolUse"]
  stopEv["Stop"]
  denied["PermissionDenied"]
  loaded["InstructionsLoaded"]
  kinds --> pre
  kinds --> post
  kinds --> stopEv
  kinds --> denied
  kinds --> loaded

Hook kinds, plus only the events named in the survey. The full event list was not copied.

flowchart TB
  oldName["Old name Claude Code SDK"]
  agent["Claude Agent SDK"]
  tools["Custom tools doc"]
  plugs["Plugins doc"]
  removed["TS SDK V2 session API marked removed"]
  npm["npm names not confirmed"]
  oldName --> agent
  agent --> tools
  agent --> plugs
  agent --> removed
  agent --> npm

Name migration that the survey states. The npm node is a gap, not a package name.

User story

A Claude Code skill file loads from a folder. An API skill is posted, workspace-scoped, and needs code execution.

Baseline

CLAUDE.md and path-scoped rules are advisory. Output style Concise was called out week 34 (17–21 August 2026).

Useful

A hook or a mod is what enforces. Week 14 adds a PermissionDenied hook and a per-tool MCP result cap, ceiling 500000.

Fail

Do not treat the Skills API and a SKILL.md file as the same install. Do not invent npm names for the Agent SDK. computer_toolset_20260801 is unverified.

sequenceDiagram
  participant User
  participant Market as Marketplace
  participant Plugin
  participant Skill
  participant Hook
  participant Mod
  User->>Market: Install
  Market->>Plugin: Bundle
  Plugin->>Skill: /plugin:skill
  Plugin->>Hook: Settings hooks
  Plugin->>Mod: In-process handlers

Install sequence. MCP, LSP, monitors, bin/ on PATH, and settings are also in a plugin and are not drawn (six-participant cap).

Default subset

Seven categories on the Categories tab. The tables here are the full spec.

Repos with a survey star count (unaudited)

Repo	Stars	Note	Badge	Source
anthropics/claude-plugins-official	37348	Official marketplace. Auto-added. Manifest schema v0.4 appears in this repo.	~	SRC-003
anthropics/claude-code	149161	Official repo, not a community fork. Demo marketplace lives inside it. Star count is the repo, not a plugin census.	~	SRC-005
obra/superpowers	294849	Author repo named in the survey.	~	SRC-006
affaan-m/everything-claude-code	272104	Author repo named in the survey.	~	SRC-007
wshobson/agents	40174	Author repo named in the survey.	~	SRC-008
agentskills/agentskills	25880	Skills spec repo.	~	SRC-009
anthropics/skills	179515	Marketplace name anthropic-agent-skills. Also named as a topic marketplace.	~	SRC-010
modelcontextprotocol/servers	90983	MCP servers repo.	~	SRC-022
modelcontextprotocol/mcpb	2129	MCPB repo.	~	SRC-023
musistudio/claude-code-router	37524	Community router. Release v3.0.22 published 2026-08-24. npm @musistudio/claude-code-router. Gateway 127.0.0.1:3456. Described as now a multi-agent control plane.	~	SRC-031
thedotmack/claude-mem	95479	Persistent cross-session memory plugin.	~	SRC-033

Built-in mods plugins and samples

Name	Note	Badge
cc-plugin-diff	Built-in	✓
cc-plugin-agents-md	Built-in	✓
cc-plugin-telemetry	Built-in	✓
cc-plugin-sec-default	Built-in	✓
cc-plugin-you-should-know	Built-in, off by default	✓

Name	Note	Badge
token-weather	Named sample. Repo URL not fetched.	??
blast-radius	Named sample. Repo URL not fetched.	??
replay-theater	Named sample. Repo URL not fetched.	??

Hook facts that were actually written down

Item	Badge
Kinds: shell, HTTP, prompt, agent, MCP-tool	✓
Events named: PreToolUse, PostToolUse, Stop, PermissionDenied, InstructionsLoaded	✓
Full hook event list was not copied from the page body (GAP-13)	~
Week 14 (v2.1.86–v2.1.91, 30 March–3 April 2026): PermissionDenied hook, defer on permissionDecision, maxResultSizeChars ceiling 500000	~
Changelog also mentions asyncRewake, InstructionsLoaded, monitors	~
bin/ on PATH in v2.1.91, week of 30 March–3 April 2026	✓

Same facts as the Markdown twin

These rows are the rest of the locked survey, so the HTML is not a thinner fact set.

Topic	Fact	Badge
Skills API examples	The guide examples mention claude-opus-5-5. That is not a model review.	✓
Safe-mode flag	`--safe-mode` is a named org control. The survey does not say that skills and MCP stay loaded under it.	~
Computer use	CLI research preview on macOS Pro/Max, week 14.	~
Router release	v3.0.22 published 2026-08-24 (24 August 2026). npm @musistudio/claude-code-router. Gateway 127.0.0.1:3456.	✓
Plugin eval	Plugin eval is week 37. The survey does not say what it measured.	~
Indexed only	Agent teams, dynamic workflows, and channels are indexed at the llms.txt URL. The channels page is indexed, not summarised.	~
Community catalog	The survey's name is community catalog (that spelling): anthropics/claude-plugins-community. GitHub page not fetched. No URL here.	??
Reserved names	Reserved marketplace names are enforced. The names themselves were not listed.	✓

flowchart TB
  survey["Survey 3 October 2026"]
  gh["GitHub API 403 no fork or pushed_at"]
  pages["Three GitHub pages not fetched"]
  modsWeek["Mods ship week not pinned"]
  toolset["computer_toolset_20260801 unverified"]
  proxies["Proxy repos search hits only"]
  survey --> gh
  survey --> pages
  survey --> modsWeek
  survey --> toolset
  survey --> proxies

Gaps called in the survey. A gap is unverified, not proof the thing is false.

ID	Badge	Gap
GAP-01	??	No pushed_at and no fork counts. GitHub API returned 403.
GAP-02	??	Official marketplace plugin list was not enumerated. This page is not a plugin catalogue.
GAP-03	??	anthropics/claude-plugins-community is named in the marketplaces doc. Its GitHub page was not fetched. No URL is given here.
GAP-04	??	anthropics/knowledge-work-plugins is named as a topic marketplace. The repo was not fetched. No URL is given here.
GAP-05	??	claude-code-playground is where samples token-weather, blast-radius, and replay-theater are named. The repo URL was not fetched.
GAP-06	??	1rgs/claude-code-proxy and fuergaosi233/claude-code-proxy were search hits only. Stars were not fetched. Not verified projects beyond that.
GAP-07	??	skills.sh leaderboard counts were not taken.
GAP-08	??	claude.ai Projects, custom instructions, and Cowork plugin pages were seen only via snippets.
GAP-09	??	Mods ship week is not pinned. The What's New index stops at week 37 (7–11 September 2026) without a mods entry. No week-37 URL was in the survey.
GAP-10	??	computer_toolset_20260801 was search synthesis and was not re-fetched. Unverified. Not treated as a real tool id.
GAP-11	??	Agent SDK npm package names were not confirmed. None are listed.
GAP-12	~	Star counts below are the survey figures and are unaudited.
GAP-13	~	The full hook event list was not copied from the hooks page body.
GAP-14	??	Agent SDK tool-use and computer-use pages were search hits and were not fully fetched. No URLs were recorded for them.
GAP-15	~	The mods admin doc was linked and not fully fetched.
GAP-16	~	The desktop-extensions page was not fully fetched. It is the source for the .dxt to .mcpb rename.
GAP-17	~	Cowork custom connectors must be publicly reachable. That is a help-centre snippet, not a fully fetched page, and no URL was recorded.
GAP-18	~	Handoff 5 says model routing is the largest community fork. Fork counts were not available (GAP-01). Other named repos have higher unaudited star counts. Stars are not forks. The handoff line is not a measured ranking.

flowchart LR
  fetched["Page cited and treated as fetched"]
  partial["Snippet, index, or not fully fetched"]
  missing["Named in search, page not fetched"]
  fetched --> partial
  partial --> missing

Reading order for badges: fetched, then partial, then not fetched.

This pass did not re-fetch pages. ✓ means the survey treats the URL as fetched. There is no ✓✓ or ✓✓✓.

ID	Tier	Status	Name	URL
SRC-001	T1	✓ Fetched	Mods overview	https://code.claude.com/docs/en/plugins/mods/overview.md
SRC-002	T1	~ Not fully fetched	Mods admin	https://code.claude.com/docs/en/plugins/mods/admin.md
SRC-003	T2	✓ Fetched	claude-plugins-official	https://github.com/anthropics/claude-plugins-official
SRC-004	T1	✓ Fetched	Anthropic marketplaces	https://code.claude.com/docs/en/plugins/anthropic-marketplaces.md
SRC-005	T2	✓ Fetched	claude-code repository	https://github.com/anthropics/claude-code
SRC-006	T3	✓ Fetched	obra/superpowers	https://github.com/obra/superpowers
SRC-007	T3	✓ Fetched	everything-claude-code	https://github.com/affaan-m/everything-claude-code
SRC-008	T3	✓ Fetched	wshobson/agents	https://github.com/wshobson/agents
SRC-009	T2	✓ Fetched	Agent Skills spec	https://github.com/agentskills/agentskills
SRC-010	T2	✓ Fetched	anthropics/skills	https://github.com/anthropics/skills
SRC-011	T1	✓ Fetched	Skills API guide	https://platform.claude.com/docs/en/build-with-claude/skills-guide
SRC-012	T1	✓ Fetched	Features overview	https://code.claude.com/docs/en/features-overview.md
SRC-013	T1	~ Indexed only	memory.md indexed beside the features overview. Full URL was not in the survey.	(no URL in the survey)
SRC-014	T1	✓ Fetched	Output styles	https://code.claude.com/docs/en/output-styles
SRC-015	T3	?? Counts not taken	skills.sh	https://www.skills.sh/
SRC-016	T1	✓ Fetched	Engineering post, 18 December 2025	https://www.anthropic.com/engineering/equipping-agents-for-the-real-world-with-agent-skills
SRC-017	T1	✓ Fetched	Hooks	https://code.claude.com/docs/en/hooks
SRC-018	T1	~ Indexed	llms.txt index, including agent teams, dynamic workflows, and channels	https://code.claude.com/docs/llms.txt
SRC-019	T1	~ Indexed	Channels	https://code.claude.com/docs/en/channels.md
SRC-020	T1	✓ Fetched	Connectors directory	https://claude.com/docs/connectors/directory
SRC-021	T1	✓ Fetched	Building MCPB	https://claude.com/docs/connectors/building/mcpb
SRC-022	T2	✓ Fetched	MCP servers repo	https://github.com/modelcontextprotocol/servers
SRC-023	T2	✓ Fetched	MCPB repo	https://github.com/modelcontextprotocol/mcpb
SRC-024	T1	~ Not fully fetched	Desktop extensions (.dxt renamed to .mcpb)	https://www.anthropic.com/engineering/desktop-extensions
SRC-025	T1	✓ Fetched	Claude Code MCP	https://code.claude.com/docs/en/mcp
SRC-026	T1	✓ Fetched	Agent SDK overview	https://code.claude.com/docs/en/agent-sdk/overview
SRC-027	T1	✓ Fetched	Agent SDK custom tools	https://code.claude.com/docs/en/agent-sdk/custom-tools
SRC-028	T1	✓ Fetched	Agent SDK plugins	https://code.claude.com/docs/en/agent-sdk/plugins
SRC-029	T1	✓ Fetched	Claude apps gateway	https://code.claude.com/docs/en/claude-apps-gateway
SRC-030	T1	✓ Fetched	LLM gateway	https://code.claude.com/docs/en/llm-gateway
SRC-031	T3	✓ Fetched	claude-code-router	https://github.com/musistudio/claude-code-router
SRC-032	T3	✓ Fetched	LiteLLM Claude Code autorouter tutorial	https://docs.litellm.ai/docs/tutorials/claude_code_autorouter
SRC-033	T3	✓ Fetched	claude-mem	https://github.com/thedotmack/claude-mem
SRC-034	T1	✓ Fetched	Changelog (mentions Added Claude Mods and $.ui.selection())	https://code.claude.com/docs/en/changelog
SRC-035	T1	~ Listed	What's New, 2026 week 14	https://code.claude.com/docs/en/whats-new/2026-w14
SRC-036	T3	✓ Fetched	claude-code-router v3.0.22	https://github.com/musistudio/claude-code-router/releases/tag/v3.0.22

Decisions

DEC-01 to DEC-05 are the five handoffs. Nothing else was decided in this edition.

Limitations

Formative landscape, 3 October 2026. Not a security sign-off.
Not a plugin catalogue (GAP-02).
Star counts unaudited (GAP-12). No fork counts (GAP-01).
Handoff 5 is quoted, not converted into a ranking (GAP-18).
No personal stack was in the survey.
Tab clicks were not exercised in a browser in this pass. Diagrams were render-checked with Mermaid CLI 11.4.2.