AI app store glossary

49 terms for the ChatGPT and Claude app stores and the MCP concepts their listings use. Each is defined in one sentence, then followed by what OpenApps data shows on October 13, 2026.

Terms: 49
Stores: ChatGPT, Claude
Also covers: MCP, ranks, countries
Figures for: Oct 13, 2026

ChatGPT apps, plugins and GPTs compared

ChatGPT app directory, Oct 13, 2026. 103 more listings sit in smaller id families (curated plugins, OpenAI connectors, connectors and templated apps).
Kind	What it is	In the directory
App	An Apps SDK app: an MCP server, with an optional interface shown in the chat	5,609
Plugin	A listing in the plugins_ id family, shown beside apps	899
GPT	A custom ChatGPT made in the GPT builder, kept apart from the app directory	Not tracked

Claude connectors, desktop extensions, plugins and skills compared

Claude directory, Oct 13, 2026. 4,192 listings in all.
Kind	Where it runs	Listed
Connector A remote MCP server you connect once	On the publisher's servers	808
Desktop extension A local MCP server in one package	On your computer, in the Claude desktop app	132
Plugin An installable bundle for Claude Code	In Claude Code	3,252
Skill A folder of instructions and scripts	Loaded when a task needs it	Inside plugins

A

AI app store: An AI app store is the directory inside an AI assistant where you find and add third-party apps, connectors or plugins that give it new tools and data.
App directory: An app directory is the browsable catalog inside an AI assistant where the store lists its apps by category, collection and rank.
App id family: An app id family is the prefix that starts a ChatGPT app id, such as plugin_asdk_app_ for Apps SDK apps or plugins_ for the plugins family.
Apps SDK: The Apps SDK is OpenAI's framework for ChatGPT apps: an MCP server supplies the tools, and optional web components draw the app's interface in the chat.
Auth-gated server: An auth-gated server is an MCP server that requires the user to sign in before it will list or run its tools.

C

Category list: A category list is ChatGPT's full ranked list of every app in one category, such as Productivity or Finance, in the store's own order.
ChatGPT app: A ChatGPT app is a listing in ChatGPT's app directory that connects ChatGPT to an outside service, so it can use that service's tools during a chat.
Cohort rank: Cohort rank is an app's position among only the apps in the list at both times compared, so arrivals and departures above it don't count as moves.
Connector (Claude): A Claude connector is a remote MCP server listed in Claude's directory that you connect once, so Claude can use that service's tools and data.
Country availability: Country availability is the set of countries where a store lists an app; in ChatGPT it changes which apps people see, not the order they appear in.
Cross-store product: A cross-store product is one product with a listing in both ChatGPT and Claude, linked on OpenApps so you can compare the two listings side by side.

D

Desktop extension: A desktop extension is a local MCP server, packaged as one file, that installs in the Claude desktop app with one click and runs on your own computer.
destructiveHint: destructiveHint is an MCP tool annotation that, when true, warns that the tool may delete or overwrite data rather than only add to it.

E

Editorial collection: An editorial collection is a short themed list in ChatGPT's directory, such as New & Noteworthy or Small Business, that mixes apps from several categories.

F

Featuring: Featuring is a placement on a store's front page, such as a home shelf or an editorial collection, that puts an app in front of people browsing the store.

G

Geo-restricted app: A geo-restricted app is one a store lists in some countries but not others, so people in the missing countries can't find or add it.
GPT: A GPT is a custom version of ChatGPT made in the GPT builder, with its own instructions, files and actions; GPTs are not part of ChatGPT's app directory.

H

Home shelf: A home shelf is a row of apps on the front page of ChatGPT's app directory, and each one shows the top of an existing list rather than a separate pick.

I

Insertion wave: An insertion wave is a burst of new listings placed above existing ones, which pushes every app below down in raw rank though none of them changed.

L

Launch lag: Launch lag is the time from the creation of a ChatGPT app's id to the day the app first appears in the directory.
Listing: A listing is one app's entry in one store: its name, description, icon, category or tags, and links, as the store shows them.
Listing change: A listing change is a new version of a listing's record, such as an edited name, description or icon.

M

MCP (Model Context Protocol): MCP (Model Context Protocol) is an open protocol that lets an AI application use outside tools and data through a standard client and server interface.
MCP server: An MCP server is a program that offers tools, resources or prompts over the Model Context Protocol, so an AI client can find and use them.
Migration batch: A migration batch is a large block of listings a store publishes at once, so they share a go-live time though their ids were created months apart.
Most popular (Claude): Most popular is Claude's main ranked list, built from three per-kind lists joined end to end, so a position only compares listings of the same kind.

O

OAuth: OAuth is the open standard for giving an app access to your account on another service without sharing your password; MCP uses it for remote servers.
outputSchema: outputSchema is an optional JSON Schema on an MCP tool that describes the structured result the tool returns, so a client can check and parse it.

P

Plugin (ChatGPT): A ChatGPT plugin is a listing whose id starts with plugins_ rather than the Apps SDK prefix; the store shows it beside apps, in the same categories.
Plugin (Claude): A Claude plugin is an installable bundle for Claude Code that can package skills, slash commands, subagents, hooks and MCP servers under one name.
Popular (ChatGPT): Popular is ChatGPT's main ranked collection in the app directory, and its top apps form the Popular shelf at the head of the directory's front page.
Publisher: A publisher is the company or person a store names as responsible for a listing.

R

Rank: A rank is an app's position in an ordered store list, counted from #1 at the top; it is an order, not a count of users or installs.
Rank drift: Rank drift is the slow, steady slide of apps lower in a long list as new apps keep arriving above them, which looks like decline but isn't.
Raw rank change: Raw rank change is the difference between an app's position now and earlier, which counts apps arriving or leaving above it as if the app itself moved.
readOnlyHint: readOnlyHint is an MCP tool annotation that, when true, says the tool only reads and does not change anything in its environment.
Remote MCP server: A remote MCP server runs on the publisher's own infrastructure and is reached over the internet at a URL, unlike a local server on the user's computer.
Retention-weighted ranking: A retention-weighted ranking orders apps partly by whether people keep using them after trying them, not only by how many try them.
Right-censoring: Right-censoring is the shortfall at the recent end of a time series, where events have begun but aren't recorded yet, so recent weeks look like a slump.

S

Skill: A skill is a folder of instructions, scripts and resources that Claude loads only when a task calls for it, adding know-how rather than new tools.
Skills-only plugin: A skills-only plugin is a Claude plugin that carries skills and nothing else: no MCP server, commands or hooks.
SSE transport: The SSE transport is MCP's older remote transport: the server sends messages over an open Server-Sent Events stream, and the client posts to a second URL.
Streamable HTTP: Streamable HTTP is MCP's standard remote transport: a client sends JSON-RPC messages to one HTTP endpoint, and the server replies once or streams several.

T

Tag list (Claude): A tag list is one of Claude's directory lists for a single tag, such as a department, an industry or what the listing acts on, ranked by popularity.
Tool (MCP): An MCP tool is an action a server offers to the model, described by a name, a description and a JSON Schema for its inputs.
Tool annotations: Tool annotations are optional hints on an MCP tool, such as readOnlyHint, that tell a client how it behaves; they are the server's claims, not guarantees.
tools/list: tools/list is the MCP request a client sends to a server to get the name, description and input schema of every tool it offers.
Trending (Claude): Trending is a short Claude list of listings the store marks as trending, beside a longer Connectors trending list; OpenApps shows their order, not a score.

W

Went live (ChatGPT): Went live is the day a ChatGPT app first appears in the store's directory; ChatGPT gives no launch date, so OpenApps uses it as the app's go-live date.