Ian Lurie, May 13, 2026
Agents, Gems, GPTs… I sure wish all these platforms used the same vocabulary. For now, though, I’ve tried to put together a page that tells you which feature on which platform does what. When the underlying feature is the same across platforms, the description is the same too — so you can spot at a glance where the platforms genuinely match up.
| Concept | Claude | ChatGPT | Gemini |
|---|---|---|---|
|
Reusable assistant
Something repeatable. Think instructions, context, and rules that you can invoke in multiple sessions to produce consistent results.
|
Skill A packaged assistant with custom instructions and uploaded resources (optional), reusable across chats. | Custom GPT A packaged assistant with custom instructions and uploaded resources (optional), reusable across chats. | Gem A packaged assistant with custom instructions and uploaded resources (optional), reusable across chats. |
|
Agents
Agents perform multi-step tasks. This is what most of us think of when we think “AI.” You give it an instruction, and the agent goes and works its magic, returning a result.
|
Workflow / Cowork Cowork (a desktop tool for non-developers) or Claude Code (for developers and the nerds among us). Claude Desktop does similar stuff. Drives tasks across files, connectors, and code. | Agent Mode Fires on a task-by-task basis from the composer. Plans and executes using a virtual browser, code execution, and connectors. | No single named feature The closest thing to “agents” is a combination of Deep Research and Canvas. You tie them together. |
|
Persistent workspace
A set of instructions, files, and a chat history the model can use to carry out a specific type of task without re-explanation.
|
Project A workspace with custom instructions, uploaded files, and its own separate chat history. Context stays within the project. | Project A workspace with custom instructions, uploaded files, and its own separate chat history. Context stays within the project. | Gem + Drive, or NotebookLM Gemini doesn’t have “Projects” per se. They have a combination of Gems, Drive access, and NotebookLM. Don’t let the multiple tools scare you. It’s very, very powerful. |
|
Custom instructions
The “system prompt” we’ve all heard so much about. They apply to every chat, no matter what.
|
User preferences / Styles Global instructions about you and how to respond. Applies to every chat unless overridden inside a Skill or Project. | Custom instructions Global instructions about you and how to respond. Applies to every chat unless overridden inside a Custom GPT or Project. | Saved info Global instructions about you and how to respond. Applies to every chat unless overridden inside a Gem. |
|
App and service connectors
How you connect to other services like Google Drive. Doesn’t include MCP servers or custom API connections.
|
Connectors First-party connections to external apps. | Connectors / Apps First-party connections to external apps. | Workspace integration / Extensions It’s Google, so native integration with Gmail, Docs, Sheets, Drive, Calendar, and Meet built in. Otherwise, first-party connectors to external apps. |
|
Command-line agents
Direct, non-GUI access to the AI. It’s a great nerd flex, and it’s the most powerful way to access the model.
|
Claude Code Command-line tool that drives the model from the terminal. Also has IDE integration with VS Code and other tools. | Codex CLI Command-line tool that drives the model from the terminal. | Gemini Code Assist / Gemini CLI Command-line tool that drives the model from the terminal. Also has IDE integration with VS Code and other tools. |
|
Project context file (for command-line agents)
A markdown file placed in your project root or in the directory tree. The CLI agent reads it before performing a task. This is the CLI agent’s superpower. Learn to use it!
|
CLAUDE.md A markdown file the agent loads before it executes any task within that directory tree. Note that Claude will accept AGENTS.md as well. | AGENTS.md A markdown file the agent loads before it executes any task within that directory tree. | GEMINI.md A markdown file the agent loads before it executes any task within that directory tree. |
This is how I teach the shit out of everything. Got questions? Reach out to me! Seriously, I love to help out:
Or, leave a comment below: