Claude Skills vs ChatGPT GPTs vs Gemini Gems: 2026 Comparison

All three are vendor-specific ways to add persistent specialization to an AI model. They differ in instruction depth, portability, and ecosystem.

**Claude Skills** — A SKILL.md file plus optional supporting files (templates, scripts, examples). The skill tells Claude how to do a specific task, with reusable instructions, tool restrictions, and references. Released under an open standard in December 2025; 32 agent tools now read the same format.

**ChatGPT GPTs** — A custom version of ChatGPT with a system prompt (~8K char limit), optional file knowledge, optional Actions (API integrations), and conversation starters. Distributed through the GPT Store, which now hosts 3M+ GPTs. ChatGPT-only.

**Gemini Gems** — A custom version of Gemini with a system prompt (~4K char limit) and optional knowledge files. Lives inside the Gemini app and Google Workspace stack. Google-only.

In one line: *a Skill tells the agent how to do X. A GPT or Gem is a vendor-specific custom assistant.*

This is the biggest difference in 2026 and the one most buyers miss.

**Skills are portable.** The SKILL.md standard is read by Claude Code, Claude Agent SDK, Codex CLI, Gemini CLI, Cursor, JetBrains Junie, AWS Kiro, Block Goose, and 24 other tools as of March 2026. Write a skill once, run it in any of them. This is unprecedented for vendor-originated AI formats.

**GPTs are ChatGPT-only.** A GPT lives inside ChatGPT.com or the OpenAI API. You cannot run a GPT inside Claude, Gemini, or Cursor. The GPT Store has scale (3M+ GPTs) but everything is locked to the OpenAI ecosystem.

**Gems are Google-only.** They live inside the Gemini app and Workspace. You cannot run a Gem outside Google's products.

If your AI strategy involves more than one model or one platform, Skills are the only future-proof choice.

How much can each format actually do?

**Claude Skills**: No practical instruction limit. A Skill can include reference docs, code templates, tool restrictions (`disallowed-tools` in frontmatter), and chained sub-skills. Hooks let you run setup/teardown code. This is the most expressive of the three.

**ChatGPT GPTs**: ~8,000 character system prompt + up to 20 files (~512MB each) for retrieval + Actions (OpenAPI-defined API calls). Actions are powerful but require you to host the API. Conversation starters help users discover capabilities.

**Gemini Gems**: ~4,000 character system prompt + knowledge files. No equivalent to Actions. Tight integration with Google Workspace data (Docs, Sheets, Gmail) inside the Workspace tier.

For agents that need to follow complex, multi-step procedures with strict guardrails, Skills are the only viable choice.

GPTs win on distribution. The GPT Store has 3M+ GPTs and is the default discovery surface for 800M+ weekly ChatGPT users. If you want a hobby agent in front of millions of consumers, build a GPT.

Claude Skills distribute through standalone marketplaces — OpenClaw, Agensi, ClaudeSkills.info, LobeHub Skills (169,739 indexed), and Skills.sh. Each is curated to a different degree. OpenClaw focuses on 32 production-grade skills with security review and channel deployment; the larger directories prioritize breadth.

Gemini Gems distribute inside the Gemini app for Workspace users. No public store.

Where can you actually run these?

**Skills via OpenClaw**: Run on Telegram, Discord, and WhatsApp through OpenClaw's deployment layer. Persistent memory across conversations. Deploy in under 2 minutes. Anthropic also ships an official Claude Code Channels plugin for Telegram, Discord, and iMessage (requires Pro/Max + v2.1.80+).

**GPTs**: Run inside ChatGPT.com. There is no first-party Telegram, Discord, or WhatsApp integration. Third-party bridges exist but break frequently when OpenAI ships changes.

**Gems**: Run inside the Gemini app on web and mobile. No channel integration.

If you need an AI agent that lives where your users already chat — Telegram, Discord, or WhatsApp — Skills are the only viable format in 2026.

**Claude Skills**: Skills themselves are typically free or low-cost on standalone marketplaces ($7.99–$49.99 on OpenClaw). The underlying Claude API or subscription is what you pay for usage. Anthropic's new Agent SDK credit (starting June 15, 2026) gives commercial Pro/Max users a separate monthly budget for headless agent runs.

**ChatGPT GPTs**: Free to build, free for ChatGPT Plus users to use. OpenAI piloted a revenue share program for top GPT builders but it's restricted.

**Gemini Gems**: Free for Gemini app users. No marketplace monetization.

For builders, OpenClaw's marketplace pays 80% revenue share on skill sales — the most generous of the lot in 2026.

Quick decision tree:

• **You need an agent on Telegram, Discord, or WhatsApp** → Claude Skills via OpenClaw. Nothing else ships there in production.
• **You want maximum consumer reach inside ChatGPT** → Build a GPT.
• **You live entirely inside Google Workspace** → A Gem is fine.
• **You need portability across multiple AI tools and CLIs** → Skills, because of the SKILL.md open standard.
• **You need an agent that follows a strict 30-step procedure** → Skills, because the instruction format has no practical ceiling.
• **You want to teach yourself agent building end-to-end** → The OpenClaw Mastery Course walks through skill structure, deployment, and security in 50 pages.

For most professional use cases in 2026, Claude Skills are the right primitive. The open-standard portability ended the vendor-lockin question.