Capability 03

A custom version you build and share.

Exact name Custom assistant

What it is.

A version of the tool set up with its own instructions and material, which you or your colleagues can pick and use. ChatGPT's GPTs and Google's Gems are the best-known examples.

What your tool calls it.

Your tool · ChatGPT GPTsretiring ChatGPT workspace agents GPTs (retiring Dec 11, 2026) · ChatGPT workspace agents (Business, Enterprise, Edu)

GPTs: Custom versions of ChatGPT that a creator builds and shares. OpenAI is retiring them and moving them to plugins.
ChatGPT workspace agents: Agents that members of a company or school ChatGPT workspace build to run repeatable tasks and workflows. Not available on personal accounts.

Your tool · Claude None No shareable assistant found.

Your tool · Gemini Gemsretiring Gems (being replaced by skills)

Gems: Named custom versions of Gemini, each with its own instructions and optional knowledge files. A Gem can be shared with others and also shows up in the Gemini side panel in Google Workspace.

Your tool · Microsoft Copilot Agent Builder Copilot Studio agents, built in Agent Builder or Copilot Studio

Agent Builder: Microsoft's tool for creating declarative agents inside Copilot.
Copilot Studio: not described on a first-party page read in this research

Also at Microsoft Copilot: Declarative agents

Your tool · Perplexity None Perplexity has nothing like it. That’s an answer, not a gap.

Your tool · Grok Shared Bots Shared Bots (formerly Team Bots)

Shared Bots: A Grok Bot published for a team to use together as one Bot, which colleagues can also talk to in Slack. A separate option shares a copy of a Bot's setup by link.

Your tool · Meta AI and Muse None Nearest: Meta Business Agent, which serves customers.

Your tool · Mistral Vibe Agentsretiring Agents (legacy, retiring into Skills)

Agents: Named helpers with their own instructions, tools and attached Libraries. They can be shared with specific people as Collaborator or Viewer, or with the organisation. Being replaced by Skills.

Pick your tool to see its answer first:

The other seven

ChatGPT

GPTs (retiring Dec 11, 2026) · ChatGPT workspace agents (Business, Enterprise, Edu)

Claude

None — no shareable assistant found

Gemini

Gems (being replaced by skills)

Microsoft Copilot

agents, built in Agent Builder or Copilot Studio

Perplexity

None

Grok

Shared Bots (formerly Team Bots)

Meta AI and Muse

None (nearest: Meta Business Agent, which serves customers)

Mistral Vibe

Agents (legacy, retiring into Skills)

Why it matters.

This is the capability most in flux. Of the five vendors that have one, three are retiring theirs:

OpenAI is moving GPTs into plugins, and they're due to retire on December 11, 2026, later for some Enterprise workspaces. Its workspace agents, for Business, Enterprise and Edu, stay.
Google is replacing Gems with skills.
Mistral is retiring its Agents in favour of Skills.

Grok went the other way, adding Shared Bots. Our view: if you're about to build one, look at a saved method it follows first. That's where most of these are heading.

Words that trip people up.

Agent. Microsoft calls its custom assistants agents. Elsewhere, "agent" usually means something that works through a job on its own. More on "agent" →
Bot. At Grok, "Grok Bot" is the product, "a Bot" is one agent, and "Shared Bots" are the team version, formerly Team Bots. More on "bot" →
Gems' dates. Google's help page says personal Gems (for users 18 and over) become read-only on November 17, 2026 and are removed on December 17, 2026, with later dates for business and education accounts. An earlier Google post said something different, so check the help page.

Close to this, but not it.

Gemini Gems from Google Labsretiring Not a match: Interactive AI mini-apps that run a set workflow, rather than a chat assistant with instructions and knowledge.

Meta AI and Muse Meta Business Agent Not a match: It answers a business's customers in WhatsApp, Messenger and Instagram. It is not a packaged bot that colleagues use.

Meta AI and Muse AI Studioretired Not a match: A tool for making AI characters to chat with, and creating or editing them is no longer possible.

Mistral Vibe Skills Not a match: Shareable to a workspace, but a method file loaded when relevant rather than a named bot you chat with

Next to it.

06 A saved method it follows

In ChatGPT: Skills (Business, Enterprise, Healthcare, Edu)

In Claude: Skills

In Gemini: skills (replacing Gems)

In Microsoft Copilot: skills — inside Copilot Cowork, paid licence

In Perplexity: Skills (replaced Workflows, Sept 23, 2026)

In Grok: Skills

In Meta AI and Muse: skills (Muse) — built by Meta only

In Mistral Vibe: Skills

Open → 02 A workspace that keeps your material

In ChatGPT: Projects

In Claude: Projects

In Gemini: notebooks in the Gemini app, synced with Gemini Notebook (formerly NotebookLM)

In Microsoft Copilot: Copilot Notebooks — paid licence (one page disagrees)

In Perplexity: Projects (formerly Spaces)

In Grok: Projects — named, never described

In Meta AI and Muse: None — nearest: Muse side chats

In Mistral Vibe: Projects

Open → 12 Add-ons from a directory

In ChatGPT: Plugin directory

In Claude: Claude directory (plugins)

In Gemini: Not found

In Microsoft Copilot: Agent Store

In Perplexity: Plugins — Discover tab, published by Perplexity

In Grok: Grok Build Plugin Marketplace (developer CLI)

In Meta AI and Muse: Not found

In Mistral Vibe: MCP Connectors directory (admins add from it)

Open →

One step up.

This is the top step.

Every step is a fine place to stop if it does the job.

What this step asks of you.

Step 05 · Build & share

Someone owns it once others depend on it, keeps it current, and retires it when it's no longer right. Decide who can use it and what data it can reach before you share it. A person reviews anything it makes before it reaches a customer.

Learn

Where we teach it.

We don't teach building one. The longer class teaches the saved method that several vendors are moving them into: Encode a method so someone else runs it.