Guide
Custom GPTs vs Gemini Gems, and the skill that replaces both
A custom GPT and a Gemini Gem do the same job: each is a named set of instructions with knowledge files for a task you repeat, which you open before you chat. Both are now being replaced by skills: on personal Google accounts Gems turn read-only on 17 November 2026 (Workspace accounts in 2027), and custom GPTs retire on 11 December 2026 (some Enterprise workspaces later). A team that keeps a GPT and a Gem for the same task can write it once as a skill, a SKILL.md file that Gemini imports and Claude and ChatGPT read, and share that one copy through AI Skill Pod, where everyone gets it in their Claude, Cursor or ChatGPT (Pro, Business, Enterprise) from one invite link.
Short answer
- Same job: instructions and files for one task.
- Gems: read-only 17 November on personal accounts.
- GPTs: retire 11 December.
- One skill can replace both.
Side by side
| Custom GPT | Gemini Gem | |
|---|---|---|
| What it holds | Instructions, conversation starters, knowledge files | A name, instructions, knowledge files |
| Files | Up to 10 files for its lifetime | From your device, Drive (read at the latest version) or a NotebookLM notebook |
| Outside services | Actions call APIs | No custom API calls; Gemini's own tools, such as Canvas and Deep Research |
| Sharing | A link, the workspace, or the GPT store | Viewer or Editor, a link, or general access; Drive's rules at work |
| What happens next | Retires 11 December 2026; a migrated GPT becomes a skill in a ChatGPT plugin, with its files copied in; Actions don't transfer | Personal accounts: a read-only skill on 17 November 2026, removed 17 December; Workspace in March or June 2027 |
From OpenAI's help (Wayback copies and search-result text) and Gemini Apps Help, read 5 November 2026.
A worked example: one task, two assistants
Illustration: a made-up business. A recruitment agency's account managers use a "Candidate summary" GPT in ChatGPT Business, and its researchers use a "Candidate summary" Gem on personal Google accounts. The two have drifted: the GPT lists notice periods and the Gem doesn't.
- The team lead writes one skill from the better of the two, adding the notice period, with the description "Summarizes a candidate for a client from the CV and interview notes. Use when sending a shortlist."
- She adds it to the agency's pod, so the account managers get it in ChatGPT Business once the admin adds the pod, and the researchers who also use Claude get it there.
- Researchers who stay in Gemini upload the SKILL.md before 17 November, when the Gem turns read-only.
From then on there's one summary format. When a client asks for salary expectations too, she edits the skill once.
AI Skill Pod is this site's product. Pod pricing: Free up to 3 members and 10 skills; Team $5 per seat a month from 3 seats.
Move both to one skill
- Copy the instructions from the GPT's Configure tab and the Gem's editor, and keep the original files.
- Merge them into numbered steps and one output template; keep what the better version does.
- Write the description as "Use when…", under 200 characters.
- List the GPT's Actions to rebuild as a connector; a skill doesn't call outside services by itself.
- Test it in Gemini and in Claude or ChatGPT with three real requests, then share it.
Next step: Gems or Claude skills
If the team moves to Claude, check what each format carries over. Gemini Gems vs Claude skills compares them.
Skills for this
- AI practiceTurn a prompt into a skillTurns a prompt that works into a skill the whole team can reuse, with a valid name, a when-to-use description, steps, an output template, an example, and checks.
- AI practiceContext brief for an AI assistantWrites instructions for an AI assistant or agent: role, audience, can and can't, sources of truth, tools, format, examples, edge cases, and handoff.
- AI practiceReview an MCP connector before connectingReviews an MCP server or connector before the team connects it: who runs it, each tool sorted read or write, sign-in, data, approvals, and a decision.
Questions
What's the difference between a custom GPT and a Gemini Gem?
Little in what they hold: both are a named set of instructions with knowledge files for a task you repeat, opened before you chat. A GPT can also call outside services through Actions and be listed in the GPT store; a Gem uses Gemini's own tools and reads Drive files at their latest version. Both are being replaced by skills.
What happens to custom GPTs and Gems?
On personal Google accounts, Gems become skills and turn read-only on 17 November 2026, and are removed on 17 December; Workspace accounts follow in 2027. Custom GPTs retire on 11 December 2026, some Enterprise workspaces later, and a migrated GPT becomes a skill inside a ChatGPT plugin.
Can one skill replace both a GPT and a Gem?
Yes. A skill is a SKILL.md file in the open Agent Skills format, which Gemini imports and Claude and ChatGPT read too. Write the task once, keep the description under 200 characters so it fits Claude, and share one copy instead of a GPT and a Gem that drift apart.
AI skill
Have your AI turn a prompt that works into a skill your team can reuse
Put this skill in AI Skill Pod and everyone on your team gets it in their Claude, Cursor or ChatGPT (Pro, Business, Enterprise): one invite link, free to start. Turn a prompt into a skill has your AI rewrite a GPT's or a Gem's instructions as one skill: a valid name, a description that says when to use it, numbered steps with your rules, an output template, an example and checks.
14 days free · No card needed
Sources
- OpenAI Help: Custom GPT retirement and migration FAQ — GPTs retire on 11 December 2026 (11 February 2027 for FedRAMP and Enterprise workspaces with an approved deferral); a migrated GPT's instructions become a skill in a plugin and its knowledge files are copied into the plugin's reference files; custom actions don't transfer; read from the Wayback copy of 30 October 2026 and search-result text (read 2026-11-05)
- OpenAI Help: File uploads FAQ — up to 10 files per GPT for its lifetime; Wayback copy of 18 September 2026 (read 2026-11-05)
- Gemini Apps Help: About the transition from Gems to skills — read at 18:37 JST: personal Gems become skills and turn read-only on 17 November 2026, removed 17 December; Workspace in March and June 2027; skills import SKILL.md files from other platforms; sharing skills in the coming weeks (read 2026-11-05)
- Gemini Apps Help: Use Gems in Gemini Apps — read at 19:46 JST: a Gem has a name, instructions and Knowledge files from your device, Drive or a NotebookLM notebook; a Drive file is read at its latest version (read 2026-11-05)
- Gemini Apps Help: Share a Gem from Gemini Apps — read at 18:37 JST: Viewer or Editor, a link, general access; work accounts follow Drive sharing settings (read 2026-11-05)