Custom GPTs: Build AI Agents in ChatGPT
Custom GPTs are OpenAI's no-code way to build a specialized ChatGPT agent. You give it a name, instructions, knowledge files, and optional Actions (API calls to external systems). You then share it with your team or publish to the GPT Store. No Python, no framework, no setup. For users who already pay for ChatGPT, it is the fastest agent-building path.
The 30-second version
- What: no-code specialized ChatGPT agent builder
- Who: ChatGPT Plus, Team, and Enterprise subscribers
- Price: requires ChatGPT Plus ($20/month) or higher tier
- Best at: personal assistants, team-shared workflows, GPT Store distribution
- Verdict: pick when you and your users live in ChatGPT; pick Claude Skills for portability
What Custom GPTs actually are
A Custom GPT is a chat-shaped agent that lives inside ChatGPT. You build it through the GPT Builder, a form-based interface where you describe what the GPT does, give it instructions, upload knowledge files (PDFs, docs, spreadsheets), and optionally add Actions for external API calls.
Once built, the GPT is callable from ChatGPT's sidebar. Your team can share GPTs privately within a workspace. You can also publish to the GPT Store for broader discovery. OpenAI has announced revenue sharing for GPT Store builders based on user engagement, though specifics have shifted over 2024-2026.
Key capabilities
- No-code GPT Builder inside ChatGPT
- Knowledge files (PDFs, Word, Excel, text)
- Custom instructions and persona
- Actions: API calls to external systems via OpenAPI spec
- Built-in tools: web browsing, code interpreter, DALL-E, file analysis
- Team and enterprise sharing
- GPT Store distribution and revenue sharing
Pricing
You need an OpenAI account with a paid tier to build Custom GPTs. ChatGPT Plus at $20/month is the cheapest path. ChatGPT Team adds shared workspaces. ChatGPT Enterprise adds SSO, admin controls, and unlimited usage. End users can interact with GPTs from the GPT Store at varying usage limits by tier. See OpenAI ChatGPT pricing.
Who Custom GPTs fit
- Solo users who already pay for ChatGPT and want a specialized assistant
- Small teams sharing common workflows (research, drafting, briefs)
- Builders who want GPT Store distribution to OpenAI's user base
- Marketers, writers, and operators who think in chat, not code
Who Custom GPTs do not fit
- Teams not on ChatGPT (you lose the entire distribution model)
- Workflows that need autonomous background agents (use OpenAI Agents SDK)
- Builders who want cross-client portability (use Claude Skills + MCP)
- Complex multi-agent systems (use CrewAI or Relevance AI)
Custom GPTs vs Claude Skills + MCP and Gemini Gems
| Axis | Custom GPTs | Claude Skills + MCP | Gemini Gems |
|---|---|---|---|
| Host model | GPT | Claude | Gemini |
| Build interface | GPT Builder (form) | Markdown SKILL.md | Gem editor |
| External tools | Actions (OpenAPI spec) | MCP servers (open standard) | Limited connectors |
| Distribution | GPT Store + private share | Project repos + MCP servers | Gem gallery + private |
| Cross-client portable | No | Yes (MCP standard) | No |
| Best for | ChatGPT-first teams | Claude users + dev workflows | Personal Gemini use |
Pros and cons
Pros:
- Easiest agent-building path for non-developers
- GPT Store distribution is a real reach (millions of ChatGPT users)
- Built-in tools (browsing, code interpreter, DALL-E) work out of the box
Cons:
- Locked to ChatGPT; no portability
- Actions setup (OpenAPI spec) is more friction than MCP servers
- GPT Store revenue is small for most builders
How I'd use Custom GPTs on SellerShorts
I would not build SellerShorts' internal agents as Custom GPTs. The lock-in to ChatGPT and the form-based builder do not fit our voice-rules versioning needs. But I would absolutely build a public-facing Custom GPT for Amazon-seller education and publish it to the GPT Store. The audience reach is the value, not the building model. For tool builders on SellerShorts, the same logic applies: build your agent in your favorite framework, then ship a Custom GPT version for ChatGPT distribution.
Try Custom GPTs
Get started with Custom GPTs
You need ChatGPT Plus, Team, or Enterprise to build. End users can use public GPTs from the GPT Store at the free tier's usage limits.
Selling on Amazon and want AI tools sized for your stack? See the Amazon AI hub.
Frequently asked questions
What is a Custom GPT?
A Custom GPT is a specialized version of ChatGPT you build with instructions, knowledge files, and optional Actions (API calls to external systems). You build them inside ChatGPT itself, no code required, and share them with your team or publish to the GPT Store.
Do I need ChatGPT Plus to build a Custom GPT?
Yes. Building a Custom GPT requires a ChatGPT Plus, Team, or Enterprise subscription. Users can interact with public GPTs from the GPT Store, with usage limits varying by tier.
Custom GPTs vs Claude Skills: what is the difference?
Custom GPTs live inside ChatGPT and use OpenAI Actions for external tool calls. Claude Skills work across any MCP-compatible client (Claude Desktop, Claude Code, third-party apps) and use the open MCP standard. Pick Custom GPTs if your team lives in ChatGPT. Pick Claude Skills if you want portability.
Can Custom GPTs make money?
OpenAI announced GPT Store revenue sharing for builders, paid based on user engagement. Specifics vary by region and have shifted over 2024-2026. For most builders the revenue is modest; treat Custom GPTs as a distribution channel, not a primary income source.