Short answerA Custom GPT answers within a chat using instructions, files and Actions. Platforms that sell "AI agents" usually add planning, tools and multi-step work. Decide if you need answers or autonomous tasks before choosing.
| Custom GPT style assistant | AI agent style | |
|---|---|---|
| Main job | Answer and advise in a chat | Complete tasks with tools |
| Steps | Usually one turn at a time | Plans and runs several steps |
| Risk | Wrong answer | Wrong action |
| Examples in this guide | Hosted page, Claude Project | Relevance AI, Botpress, Dify |
Choosing
If your GPT only answers from files, an agent platform adds cost and complexity you may not need. If it triggers real actions, give each tool explicit limits and approval steps: Actions migration. OpenAI's plugins package skills and tools (MCP): GPT vs plugin.
Check your GPT before you move it
Paste your instructions, file names and Actions schema into the free checker. It runs in your browser and builds a portable bundle. Nothing is uploaded.
Open the free checkerRelated guides
Sources
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