0->1 Engineer, Open Source AI

Summary Mozilla is building a position in open source AI through research, community, tooling, and public advocacy. A big part of that work is showing, not just telling. We need an engineer who ships fast and in public — working code and real demos that developers can install, fork, and build on. The current focus is Harbor , a Firefox and Chrome extension implementing a proposed Web Agent API that puts model choice, tool permissions, and agent oversight back in the hands of the user and the browser, rather than the vendor. Harbor is three layers: the browser extension at the bottom managing permissions, model access, and revocation; the SDK/API layer on top exposing primitives like window.ai , window.agent , and WebMCP tools; and the application and workflow layer at the top — the actual experiences being built. The thesis is that agents should only be able to do what a page explicitly declares, not free-roam the DOM. Making those layer boundaries legible is core to the role — if a developer or their coding assistant keeps reaching for the wrong primitive, that's yours to fix. If you've shipped a browser extension, authored MCP servers, run models locally with Ollama or llama.cpp, and thought seriously about prompt injection as an architectural problem rather than a prompt-level concern, this is the specific intersection we're hiring for. Beyond Harbor, Mozilla is building acr