Yahoo Halo

Revolutionizing Conversational AI

Strategy · Leadership · Research · Design 

The Halo project embarked on a visionary quest in 2016, aiming to establish Yahoo as a pioneering AI Center of Excellence. At its core, Halo represented a groundbreaking conversational assistant designed to be highly personalized and multi-modal. In my role, I led the AI conversation design initiative for Halo, developing a versatile conversational design framework and serving as a key design partner during the concept phase. These design concepts not only guided the project but also motivated the team and led to the successful launch of products on Yahoo Mail, Yahoo Search, and Facebook Messenger.

Project Vision

Halo's vision stemmed from Yahoo's unique position, combining expertise in search and content while offering neutrality in a world of tech giants pushing their ecosystems. Several key insights drove this vision:

Social & Messaging Dominance The ascent of social and messaging platforms as the primary UI for content discovery.

iGen's Chat Preference The growing preference of the iGeneration for conversational interfaces over traditional search methods.

Natural Language Interface Exploring the potential of natural language as a user interface for connected devices.

App Fatigue Challenge Addressing user and developer fatigue associated with the continuous proliferation of app installations.

Project Goals

The project was driven by several core objectives:

Enhanced User Experience Craft an AI Assistant that provides a human-like conversation experience for natural and engaging interactions.

Cross-Platform Coordination Ensure a consistent experience across multiple platforms and devices.

Knowledge and Information Organize and deliver personalized, accurate, and up-to-date information across diverse domains.

Proxy Enable the assistant to execute tasks on behalf of the user.

User Personalization Allow users to customize the assistant's appearance, tone, and information preferences.

Design Process

The Halo Project's Design Journey

Explore the innovative design process behind Halo, from conceptual modeling to captivating simulations, shaping a seamless and engaging user experience.


I gave life to the AI Conversation Assistant by personifying it, establishing a distinct visual identity for Halo that unified all stakeholders, making it easier to associate subsequent ideas and discussions with a shared entity.

Concept Modeling

I started by creating a comprehensive conceptual model aimed at gaining insights into the intricacies of the product ecosystem and the multifaceted roles played by Halo. Mapped the interaction between several touch points

Use-case Analysis

I immersed myself in a user's daily life, analyzing the myriad of topics and use cases they encounter, mapping interactions across interfaces and devices.

Conversation Design Principles

My design process was driven by fundamental conversation design principles, encompassing input validation, task switching, backtracking, timing considerations, awaiting critical input, offering choices from predefined lists, and infusing the assistant with an engaging and enjoyable personality, ensuring a delightful and fun user experience.

Scenario Building

I devised scenarios and concise narratives detailing how user personas receive assistance and accomplish tasks within specific contexts, emphasizing multi-turn dialogues; these scenarios played a pivotal role in helping the team vividly envision the user experience.

Visualizing Rich Conversations

I explored scenarios requiring multimedia content to enhance the user experience.


I developed storyboards reminiscent of graphic novels, offering ample information for the team to grasp the unfolding events, effectively capturing real-life user conversations, context, situations, and emotions in the process.

Bringing the scenarios to life

I crafted compelling simulations, using videos and animations to convey the product's features, capabilities, and usage, resulting in a captivating product story and concept simulation.


Created a 2 minute  demo to rally the concept and garner executive support

View demo ▶️


Created prototypes demonstrating coordinated and  consistent experience across multiple platforms and devices.

Implementation and Launch
From Testing to Triumph

Halo was introduced to a limited user base to gather real-world feedback and drive ongoing improvements. The concept transcended into several Yahoo products and external platforms. Users were encouraged to provide insights on conversation quality, customization options, and information relevance.

Captain on Facebook Messenger

A version of the assistant, known as Captain, was successfully launched on Facebook Messenger, announced at the Facebook F8 conference.

Yahoo launches Captain bot on Messenger →


The Halo project was a testament to Yahoo's commitment to innovation and AI excellence. As the AI conversation design lead, my role was pivotal in shaping the concept and framework, resulting in a transformative conversational assistant that not only met but exceeded user expectations. The project's success, evident in its integration into various platforms and its high-profile launch on Facebook Messenger, underscored the importance of human-centric design and continuous user feedback in creating groundbreaking AI solutions.

Prateeksha Chandraghatgi
Product Manager, Yahoo

During Q3 and Q4 of 2016, I collaborated with Vilas on the Horizontal assistant project, focusing primarily on the Halo video. Vilas had the challenging task of finding an engaging way to convey various aspects of the assistant, including intricate concepts like group assistance, multimodality, and anticipation. Since there was no established playbook for these elements, our team explored numerous iterations, considering various assets such as comic strips, animated slides, and videos to find the most suitable approach. Ultimately, I must say that I am extremely pleased with the end result, and Vilas deserves the majority of the credit. The video is not only aesthetically pleasing but also effectively accomplishes its objectives. In particular, I found that several of Vilas's strengths shone brightly during this project, including exceptional visual design skills and a keen ability to grasp and appreciate the broader context.

Conrad Wai

Vice President, Product Management, Yahoo

Vilas impressed me with his holistic, system-oriented approach to the Halo project from the outset. He has a deep appreciation for the iterative nature of great design and has proven to be an exceptional partner in crafting and revising the Halo concept deck based on feedback. His work consistently delivers beautiful and finely crafted solutions that effectively communicate our ideas to customers. What sets Vilas apart is his ability to seamlessly navigate between the big picture and meticulous details; he can effortlessly zoom out to consider high-level concepts and then dive into the nitty-gritty, whether it's selecting icons or fine-tuning animation timings.

See more of my work.