When chat is not enough – comparing AI tools
How do they compare to chat & custom GPTs?
- Custom GPTs
- Claude Projects & Skills
- Gemini Gems
- Perplexity Spaces
- Copilot Studio
- purposewrite
If you already use AI daily, you’ve probably moved past “plain chat” to these tools. And yet, the confusion usually increases, not decreases.
They all feel similar.
They all promise “custom AI.”
They all kind of work — until they don’t.
This article doesn’t explain how to use them. It explains what category of problem each tool actually solves, using Custom GPTs as the reference point.
Chat vs Custom GPTs
The first upgrade most people make
Plain chat (ChatGPT, Claude, Gemini) is stateful but ephemeral. It remembers this conversation, but nothing is fixed. Every session starts fresh. Every instruction must be re-explained. Behavior changes with phrasing, mood, or context length.
Custom GPTs are the first real step toward structure.
They let you:
- Lock in system instructions
- Upload files as persistent knowledge
- Enable tools once, not every time
The key shift:
- Chat = “Explain what you want, again.”
- Custom GPT = “This is what I am. Use me.”
But Custom GPTs still rely on one big prompt and the model’s judgment to follow it correctly. That works well for assistants — less well for processes.
Claude Projects vs Custom GPTs
Claude Projects focus on persistent context, not fixed behavior. A Project remembers files and conversations across sessions, making it ideal for long-running thinking or research. Custom GPTs, by contrast, are designed to behave consistently regardless of conversation history.
In practice:
- Use Projects when memory over time matters.
- Use Custom GPTs when consistent role and behavior matter.
Projects help you think. GPTs help you repeat.
Claude Skills vs Custom GPTs
Claude Skills break behavior into modular capabilities, while Custom GPTs bundle everything into a single system prompt. A Skill is a reusable action Claude can apply when relevant; a Custom GPT asks the model to infer everything from one instruction set.
As complexity grows:
- Skills scale better for repeated tasks.
- Custom GPTs become brittle and harder to debug.
Gemini Gems vs Custom GPTs
Gemini Gems are Google’s parallel to Custom GPTs: saved assistant roles with instructions and context. Structurally, they work the same way — prompt-driven, conversational, and model-led.
The real difference isn’t capability, but ecosystem:
- Gems fit naturally into Google Workspace.
- Custom GPTs fit better into OpenAI’s tooling.
Both are good assistants. Neither is a workflow engine.
Perplexity Spaces vs Custom GPTs
Perplexity Spaces are optimized for research, not behavior. They organize sources, searches, and answers in a shared workspace, whereas Custom GPTs focus on generating responses in a consistent voice or role.
Think of it this way:
- Spaces help you figure out what’s true.
- Custom GPTs help you decide how to respond.
Microsoft Copilot Studio vs Custom GPTs
Copilot Studio trades flexibility for determinism. It uses dialog trees, connectors, and business rules to guarantee predictable outcomes. Custom GPTs rely on probabilistic reasoning and natural language instructions.
So the trade-off is clear:
- Copilot Studio = reliability, governance, enterprise control
- Custom GPTs = speed, creativity, conversational freedom
Copilot Studio is built for systems. GPTs are built for people.
Purposewrite vs Custom GPTs
Custom GPTs are black boxes: you describe a process and trust the model to follow it. Purposewrite is a glass box: the process itself is explicitly defined — step by step, with conditions, loops, and save points, not for complete automation but for scripting repeatable Human In The Loop workflows.
The difference shows up when you:
- Easily turn an AI+Human process into an app
- Need to delegate work with confidence
- Need the same quality every time
- Require a human-in-the-loop scripted workflow
- Need to be able to save a chat and be able to reset back to that save point
- Want exact web page scraping and SEO data
- Share an app state with your team, for feedback, approval or delegation
Final mental model
- Chat → talk
- Custom GPTs / Gems → assist
- Projects / Spaces → remember & research
- Skills → repeat
- Copilot Studio → integrate systems
- Purposewrite → turn a human process into a runnable app
