Google and OpenAI both retire their custom assistant builders

Google and OpenAI both retire their custom assistant builders

29 October 2026: Google and OpenAI are each closing the feature that let users package instructions and reference files into a reusable assistant. Google's Gems become "skills" in Gemini: for personal accounts they turn read-only on 17 November 2026 and are removed on 17 December, while Workspace business, enterprise and non-profit accounts follow in March 2027. OpenAI's custom GPTs retire on 11 December 2026, with a later date of 11 February 2027 only for FedRAMP workspaces and Enterprise workspaces granted a deferral.

Not yet independently verified. Google's help page carries no publication date; we read it on 30 October and date the item to OpenAI's FAQ, which its page shows as updated on 29 October. Google says skills will gain sharing and Drive files "in the coming weeks", which we cannot yet check. We will update this when it can be confirmed, and remove this note.

Google's timetable by account type

Google's help page sets the dates by the account a person signs in with:

• personal Google accounts, aged 18 or over: Gems become skills and go read-only on 17 November, then disappear on 17 December;
• under-18 personal accounts: a later date Google has not yet given;
• Workspace business, enterprise and non-profit: March 2027;
• Workspace education: June 2027.

Opal, Google's experiment for building mini apps, and Gems by Google Labs go away in November as well. Google says it will convert each Gem to a skill automatically, but not everything comes across. Skills hold at most 100 MB of files, and if a Gem is larger the largest files are dropped first. GitHub files, audio, video, the old .doc, .xls and .ppt formats and archives such as .zip and .tar are not carried over at all. Most tools that worked inside a Gem, including Canvas, Deep Research and video and music creation, do not yet work with skills, and only 100 skills can be active at once.

What OpenAI's migration keeps and drops

OpenAI is moving custom GPTs to plugins. A GPT's creator, or a workspace admin in Enterprise, runs "Migrate to plugin" from My GPTs; the GPT's instructions become a skill inside the plugin, knowledge files become reference files and connected apps come across as apps. The selected model does not carry over, drafts and unpublished edits are lost because migration uses the last published version, and the original GPT becomes read-only.

The larger gap is custom actions. OpenAI says they "do not transfer through the migration workflow", and rebuilding one may need a custom MCP server. A migrated plugin starts private, so people who used a shared GPT get nothing until its owner shares the replacement. In affected Enterprise workspaces, new GPT creation already stopped on 26 October, and bulk migration runs through the ChatGPT Admin plugin, though listing a workspace's full GPT inventory needs an Owner.

Where a business is exposed

The risk sits with assistants that someone built once and others now rely on: a sales-proposal GPT that calls a CRM through a custom action, or a Gem loaded with policy PDFs and spreadsheets in the old Excel format. Neither vendor's automatic path keeps those whole. Two checks matter before the December dates: which GPTs call an external API through an action, and which Gems hold files in formats skills reject or exceed 100 MB. Chats held with either kind of assistant stay readable after retirement, according to OpenAI's FAQ, but a Gem's files on a personal account can only be downloaded until 17 December.

Company profile on TrustList: Google

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Sources

• Google Gemini Apps Help: About the transition from Gems to skills (read 2026-10-30), 30 October 2026
• OpenAI Help Center: Custom GPT retirement and migration FAQ (updated 2026-10-29), 29 October 2026