# Claude Skills vs Custom GPTs: Different Answers to Reuse

> Claude Skills are portable procedures; Custom GPTs are packaged chatbots inside ChatGPT. How they differ on portability, API access, sharing, and where each wins.

Verdict first: a Custom GPT is a destination — a packaged chatbot living inside ChatGPT; a Claude Skill is a capability — a portable procedure any conforming agent loads mid-task. Skills win on portability (an open standard 40+ tools read, ChatGPT-maker's Codex included), API access, and git-native sharing; GPTs win on consumer-facing packaged assistants with the Store's reach.

People compare these two because both answer "how do I stop re-explaining the same thing to my AI?" — but they answer it with opposite architectures. **A Custom GPT is a destination: a packaged chatbot you (or the GPT Store's audience) go visit. A Claude Skill is a capability: a procedure your existing agent picks up mid-task, wherever you already work.** Once you see that shape difference, every row of the comparison follows from it.

## What each one is

A **Custom GPT** is a configured instance of ChatGPT: system instructions, up to 20 uploaded knowledge files (512 MB each), optional Actions (external APIs described by OpenAPI schemas), and capability toggles like code interpreter and canvas — assembled in a web builder, used inside ChatGPT, shareable privately, by link, to a workspace, or through the GPT Store. Creating one requires a paid plan; building happens on the web only.

A **Claude Skill** is a [folder with a SKILL.md](/guides/skills/what-are-claude-skills): frontmatter that says when it applies, a Markdown body that says what to do, optional bundled scripts. It isn't a place you go — it loads into whatever session you're already in when the task matches, on claude.ai (every plan, Free included), in Claude Code, via the API, and — because the format is an [open standard](/guides/skills/agent-skills-open-standard) — in 40+ other tools.

## The comparison

| | Claude Skills | Custom GPTs |
|---|---|---|
| Shape | Procedure loaded into your session | Packaged chatbot you converse with |
| Runs in | claude.ai, Claude Code, API, Agent SDK, 40+ standard-compliant tools | ChatGPT only |
| API access | Yes — `/v1/skills` + code-execution container | No |
| Created with | A Markdown file (any editor, lives in git) | Web builder UI |
| Versioning & review | git diffs, PRs, plugin/API versions | Builder version history |
| Sharing | Repo checkout, ZIP, plugins, `/v1/skills` workspace | Link, workspace, GPT Store |
| External integrations | Bundled scripts + the agent's own tools | Actions (OpenAPI) |
| Cost to use | All Claude plans incl. Free (claude.ai) | Use varies by plan; **creation** requires paid |
| Composability | Many skills active per session, auto-routed | One GPT per conversation |

That last row is quietly the big one. Skills compose: your commit skill, migration skill, and style-guide skill all sit dormant in one session and fire per task. GPTs silo: each conversation happens inside exactly one GPT's configuration, and switching contexts means switching chatbots.

## Where each wins

**Choose skills for working procedures.** Team conventions, runbooks, format enforcement, anything engineers touch — skills live in the repo, review like code, and follow the task across tools. The [use-cases list](/guides/skills/claude-skills-use-cases) is effectively a catalog of things GPTs are the wrong shape for.

**Choose a Custom GPT for a packaged, audience-facing assistant.** A branded tutor, a product helper, a niche persona with curated knowledge — something non-technical users *visit*. The Store's distribution into ChatGPT's user base has no skills equivalent, because skills deliberately aren't products.

**Actions vs. scripts** is the one dimension where GPTs hold real technical ground: a GPT with well-built Actions calls your live APIs conversationally, while an API-attached skill runs in a container with no network access. (In Claude Code, skills pair with [MCP servers](/guides/skills/skills-vs-mcp-servers) for live integrations — that combination outclasses Actions, but it's a Claude Code answer, not a claude.ai one.)

## The direction of travel

Two 2026 facts say where this is heading. First, OpenAI introduced **Workspace Agents** (April 2026) as the org-side "evolution of GPTs" — Codex-powered, Slack-connected, schedulable, API-triggerable, with GPT-to-agent conversion promised — signaling that packaged chatbots are giving way to agents with capabilities even inside OpenAI's world. Second, and more striking: **OpenAI's Codex adopted the Agent Skills standard itself.** The procedure layer converged on Anthropic's format; the walled garden kept the storefront. If your reuse problem is "my agent should know how we do things," the ecosystem has effectively voted — write it as a SKILL.md, [install it once](/guides/skills/how-to-install-claude-skills), and it will outlive whichever chat product you're using this quarter.

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_Source: https://agentscamp.com/guides/comparisons/claude-skills-vs-custom-gpts — Guide on AgentsCamp._