chatgpt-app-builder

# Creating Apps For LLMs ChatGPT apps are conversational experiences that extend ChatGPT through tools and custom UI widgets. They're built as MCP servers invoked during conversations. ⚠️ The app is consumed by two users at once: the **human** and the **ChatGPT LLM**. They collaborate through the widget—the human interacts with it, the LLM sees its state. Internalize this before writing code: the widget is your shared surface. SPEC.md keeps track of the app's requirements and design decisions. Keep it up to date as you work on the app. **No SPEC.md?** → Read [discover.md](references/discover.md) first. Nothing else until SPEC.md exists. **SPEC.md exists?** → Read SPEC.md, then follow [architecture.md](references/architecture.md) to design the change. Update SPEC.md, then read the relevant Implementation references below before writing code. ## Setup 1. **Copy template** → [copy-template.md](references/copy-template.md): when starting a new project with ready SPEC.md 2. **Run locally** → [run-locally.md](references/run-locally.md): when ready to test, need dev server or ChatGPT connection ## Architecture Design or evolve UX flows and API shape → [architecture.md](references/architecture.md) ## Implementation - **Fetch and render data** → [fetch-and-render-data.md](references/fetch-and-render-data.md): when implementing server handlers and widget data fetching - **State and context** → [state-and-context.md](references/state-and-context.md): when persisting widget UI state and updating LLM context - **Prompt LLM** → [prompt-llm.md](references/prompt-llm.md): when widget needs to trigger LLM response - **UI guidelines** → [ui-guidelines.md](references/ui-guidelines.md): display modes, layout constraints, theme, device, and locale - **External links** → [open-external-links.md](references/open-external-links.md): when redirecting to external URLs or setting "open in app" target - **OAuth** → [oauth.md](references/oauth.md): when tools need user authentication to access user-specific data - **CSP** → [csp.md](references/csp.md): when declaring allowed domains for fetch, assets, redirects, or iframes ## Deploy - **Ship to production** → [deploy.md](references/deploy.md): when ready to deploy via Alpic - **Publish to ChatGPT Directory** → [publish.md](references/publish.md): when ready to submit for review Full API docs: [https://docs.skybridge.tech/api-reference.md](https://docs.skybridge.tech/api-reference.md)