Google Accidentally Leaks Secret COSMO AI Assistant App

Google did not mean for anyone to download this. On April 30, 2026, a fully functional experimental AI assistant called COSMO appeared on the Google Play Store.

It was published under Google’s own main developer account and carried a 1.13GB install that included a live Gemini Nano model running entirely on-device.

By the time most users noticed, it was already gone. Google pulled the listing hours after it went live, confirming the release was accidental.

What COSMO Actually Is

According to 9to5Google, which first reported the accidental listing, COSMO originates from Google Research, and its Play Store package ID is com.google.research.air.cosmo, but it was published on Google’s primary Play Store account rather than a research channel.

The listing describes COSMO as an experimental AI assistant that brings AI directly to your Android phone, helping organize daily tasks and answer complex questions while operating in the background to simplify use.

This “always-on” background presence seems to be the evolution of the Gemini Your Day philosophy, aiming to simplify the mobile experience through constant context-awareness.

After installation, the app requests several system permissions before showing a basic chat interface, reflecting its experimental state.

Skills and Capabilities of COSMO

What makes COSMO genuinely interesting is not the interface but the Skills system underneath it. Nine discrete capabilities were confirmed in the build:

List Tracker: Proactively suggests Google Keep lists based on conversation context
Document Writer: Detects when you mention needing a letter or summary and offers to draft it
Calendar Event Suggester: Listens for agreed plans and offers to schedule them automatically
Browser Agent: Automates web tasks using Google Mariner, the company’s browser automation model
Add Timer: Detects time-bound tasks in conversation and creates Clock app timers
Deep Research: Triggers a full multi-source research report for complex queries
Quick Photo Lookup: Finds relevant photos from your library mid-conversation without breaking flow
Google it: Fires a web search automatically when a quick factual answer is needed
Jargon Definitions: Interprets acronyms and technical terms and explains them in-line

The common thread across all nine Skills is proactivity. COSMO does not wait for commands but listens to context and suggests actions.

This proactive “vision” is similar to the rumored OpenAI smart screen reader, which also seeks to understand on-screen content to provide real-time assistance.

What COSMO Means For Android

As 9to5Google noted, COSMO is likely a testbed for future experiences rather than a consumer product.

Its accidental release under Google’s main account suggests it is more advanced than a typical prototype. Including a full Gemini Nano model in a 1.13GB APK also points to a near production-ready build.

This development coincides with growing chatter around Pixel’s upcoming visual redesign , where a revamped “glow” interface is expected to signal these next-gen AI capabilities.

The Browser Agent skill is the key element, built on Google Mariner, the same automation layer used in Google’s agentic browsing experiments for navigating websites, filling forms, and completing multi-step tasks.

Taken together, COSMO integrating Mariner as a conversational skill indicates testing of a fully agentic Android assistant in real device conditions.

Source: Google releases experimental ‘COSMO’ AI assistant app