What Are GPT Actions? The Complete Guide for 2026
GPT Actions are OpenAI's tool integration protocol for ChatGPT. We index 1,818 of them. Here's what they are, how they differ from MCP, and which ones are worth using.
SkillsIndex indexes 1,818 GPT Actions — all scored on security, utility, maintenance, and uniqueness. GPT Actions are OpenAI's tool integration protocol for Custom GPTs in ChatGPT. Here is a clear explanation of what they are, how they compare to MCP servers, and which ones are worth using.
What Are GPT Actions?
GPT Actions are integrations that let Custom GPTs in ChatGPT call external APIs. They are defined using OpenAPI 3.0 schemas — the same format used for REST API documentation. When a user asks a question, the GPT decides whether to call an external API, executes it via OpenAI's servers, and incorporates the result into its response.
GPT Actions were introduced in late 2023 alongside the Custom GPTs feature. They allow GPTs to go beyond text generation by fetching live data, submitting forms, querying databases, and triggering workflows — all from within a ChatGPT conversation.
GPT Actions vs MCP Servers: Key Differences
| Feature | GPT Actions | MCP Servers |
|---|---|---|
| Protocol | OpenAPI 3.0 | Model Context Protocol |
| Works with | ChatGPT only | Claude, Cursor, Windsurf, Cline, etc. |
| Where calls execute | OpenAI's servers (cloud) | Your machine or your infrastructure |
| Data stays local | No — goes through OpenAI | Yes (stdio servers) |
| Open standard | No (OpenAI-specific) | Yes (Anthropic open-sourced MCP) |
| Ecosystem size | ~1,818 on SkillsIndex | 4,133+ on SkillsIndex |
| Average quality score | 26–29/100 | 44/100 |
Why Do GPT Actions Score Lower Than MCP Servers?
One of the more surprising findings from SkillsIndex's scoring: all 1,818 GPT Actions cluster between 26–29/100, while MCP servers average 44/100. The gap comes primarily from:
- Maintenance — many GPT Actions were built for the original Custom GPTs launch (late 2023) and have not been updated since
- Security auditing — GPT Actions are harder to audit since they rely on external API endpoints rather than open-source server code
- Utility — the Custom GPT ecosystem has plateaued since OpenAI shifted focus to Agents and API-based integrations
Best GPT Actions Still Worth Using
Despite the ecosystem's challenges, several GPT Actions remain genuinely useful:
- Zapier AI Actions — connect ChatGPT to 5,000+ apps via Zapier's automation platform. Highly reliable and officially maintained.
- Wolfram Alpha — accurate computational and knowledge queries. Official integration, actively maintained.
- Code interpreter integrations — various GPT Actions that extend ChatGPT's code execution to external services
- Database connectors — GPT Actions for querying PostgreSQL, MySQL, and Airtable
Is the Future GPT Actions or MCP?
The broader AI ecosystem is converging on MCP as the cross-platform standard. OpenAI has adopted MCP support in their Agents SDK, indicating that future tool integrations will likely favor MCP over the proprietary GPT Actions format. For new integrations, MCP servers offer better cross-platform compatibility and a larger, more actively maintained ecosystem.
GPT Actions remain relevant if you are building specifically for ChatGPT users and want the simplest possible integration path within OpenAI's ecosystem.
Frequently Asked Questions
Are GPT Actions still supported in 2026?
Yes. OpenAI continues to support Custom GPTs and GPT Actions as of 2026. However, the company's development focus has shifted toward the Agents API and MCP compatibility. New GPT Action development is slowing relative to MCP server development.
How do I find the best GPT Actions?
Browse SkillsIndex's GPT Actions directory — 1,818 actions scored and ranked. Filter by category and sort by overall score. The Zapier AI Actions and Wolfram integrations consistently rank highest for utility.
What is the difference between a GPT Action and a ChatGPT plugin?
ChatGPT Plugins were an earlier, broader integration system deprecated in early 2024. GPT Actions replaced Plugins with a more structured OpenAPI-based format tied specifically to Custom GPTs. SkillsIndex indexes the legacy plugin data alongside current GPT Actions.
Can I convert a GPT Action to an MCP server?
Yes, in principle — both use API calls. The main work is rewriting the integration as an MCP server (using the MCP TypeScript or Python SDK) and configuring it for stdio transport. Some developers have published conversion guides for popular GPT Actions.
Do GPT Actions work on the free tier of ChatGPT?
Custom GPTs (and their Actions) are available to ChatGPT Plus subscribers. Free tier users have access to some GPTs in the GPT store but may have limited ability to create new GPTs with custom Actions.
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