I’ve been building chatbots with the Vercel AI SDK and ran into the point Anthropic makes that general-purpose agents perform much better when they can write and run code. We build support chatbots and I really didn’t want to run LLM-generated code on our own infra.
Cloud sandboxes are expensive, and we already have an SPA app, so I explored pushing the compute to the client using WASM instead.
So I built 1MCP – an open-source, browser-only WASM sandbox that your AI SDK chatbot can call to execute JS/TS on the client, Code Interpreter–style.
What it does
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Runs model-generated or user-generated JS/TS in the browser via WASM
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No backend required for “code execution” mode – works in a plain AI SDK chat widget
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Optional server mode to act as an MCP proxy (for CORS + extra npm packages in the bundle)
Links
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Open-source repo: https://github.com/buremba/1mcp
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Website / live demo: https://1mcp.dev