Polaris 4 - Hippocratic AI

Introducing

Polaris 4: Redefining Patient & AI Interactions for Clinical Excellence

Nov 20, 2025 | 10 min read
By Subhabrata Mukherjee,
PhD, Chief Science Officer, Co-Founder, Hippocratic AI

At Hippocratic AI, our mission is to deliver safe, empathetic, and clinically effective conversations that transform healthcare. With Polaris 4, we’re taking a bold leap forward, building on the foundation of Polaris 3 to create an AI system that feels more natural, responds faster, and ensures unparalleled clinical safety. This release isn’t just about technical upgrades, it’s about perfecting the art and science of human–AI interaction at a clinical scale. Here’s how Polaris 4 sets a new standard for healthcare AI.

A New Era of Conversational Intelligence

Polaris 4 redefines what it means for AI to engage in natural, trustworthy, and clinically precise conversations. By focusing on the subtle nuances of human interaction with tone, pacing, and empathy, we’ve crafted an AI that feels like a trusted healthcare professional. Drawing from over 115 million clinical interactions and continuous structured feedback, Polaris 4 has mastered more than 30 unique healthcare-specific skills to deliver personalized, empathetic, and effective conversations.

Hear the unique healthcare skills our AI agents have from real de-identified calls (Hippocratic AI).

Key Advancements in Interaction Intelligence

Context-Aware Tone Shaping: Polaris 4 dynamically adjusts its pace, tone, and phrasing based on the patient’s intent and preferences and the task at hand whether it’s reassuring a nervous patient, providing clear instructions, or escalating urgent concerns.
Seamless Turn-Taking: With smarter pause modeling and faster time-to-first-token, Polaris 4 minimizes interruptions and awkward silences, creating smoother, more natural exchanges.
Personalized Engagement: The system calibrates empathy, word choice, and directness to match patient preferences, ensuring conversations are both clinically complete, engaging and natural.
Intelligent Clarification: When faced with unclear inputs like ambiguous medication names or dosages and ASR mistranscriptions, Polaris 4 triggers targeted follow-ups instead of generic responses, enhancing clarity and safety.

These micro-skills work together to make every interaction feel intuitive, trustworthy, and tailored to the patient’s needs.

Performance That Powers Real-Time Care

Speed and reliability are critical in healthcare, and Polaris 4 delivers with significant performance enhancements. Compared to Polaris 3.0, we’ve achieved a 20% reduction in end-to-end latency at P99, enabling faster turn-taking, fewer “dead-air” moments, and crisper escalations to human clinicians when needed. Here’s what’s driving these gains:

Optimized LLM Architecture: Polaris 4 uses a capability preserving distillation from our custom 405B teacher model to a specialized 300B generalist backbone. This “right sized” model maintains robust reasoning while slashing latency for voice-based interactions.
Next-Gen Hardware: Upgrading from H100 to H200 GPUs, Polaris 4 leverages higher memory capacity for larger KV caches and cache-aware routing, optimizing multi-turn conversations with large prefixes.
In-House ASR Breakthroughs: Our custom automatic speech recognition (ASR) system, trained specifically for clinical phone conversations, runs 4x faster at P99 and delivers a 50% reduction in word error rate compared to state-of-the-art, off-the-shelf ASRs used in Polaris 3.

Uncompromising Clinical Safety

Safety is the cornerstone of Polaris 4. With upgrades to our safety engines, speech modules, and core conversation model, Polaris 4 achieves an unprecedented 99.9% no-error rate (0.1% no harm, 0% harm or death), surpassing the safety of prior Polaris versions and even the average human clinician for equivalent tasks.

We Are Clinically Safer Than Average Human Clinician Doing the Same Tasks

“Polaris 4 marks a major leap forward in making AI conversations even more supportive, deeply empathetic, yet clinically precise. Whether it’s reassuring a nervous patient or helping them navigate their care, Polaris 4 proves that compassion and safety can go hand in hand. With a 99.9% no-error rate, it’s setting a new standard for healthcare generative AI, and it’s exactly the kind of technology clinicians should want to support their patients”

Dr. Meenesh Bhimani, Co-founder & Chief Medical Officer

A key component of our safety harness is the clinical escalation system. As the system encounters a patient with symptoms or distress, it does a series of clinical follow-ups to make sure if it is safe to continue the conversation or warm transfer to a human nurse. In real world deployment, Polaris 4’s escalation rate has been <1%. The unprecedented accuracy of the clinical support engines has allowed the system to handle almost all scenarios autonomously; escalations are only triggered for situations where the patient truly needs clinician attention immediately.

Speech Understanding for the Real World

Polaris 4’s speech capabilities are designed to thrive in the messy, unpredictable reality of real world environments. Our contextual ASR model goes beyond single utterance processing, incorporating multi-turn conversational context to handle short utterances, ambiguous terms, and background noise with ease. Key features include:

Healthcare Specific Training: Built on curated medical corpora covering drug names, diseases, vitals, and more, our ASR achieves 2x lower word error rates than enterprise grade alternatives on clinical tasks.
Diversity in Design: Implicit prosodic modeling captures rhythm, stress, and timing, ensuring natural speech understanding across diverse patient voices and accents.
Real World Robustness: Trained on proprietary synthetic data simulating noisy environments like clinics, subways, and cafes, Polaris 4 handles dropped frames, ambiguous identifiers, and complex medical terms with dynamic weighting for real-time accuracy.

Clinical WER in Real World Patient Environment

Dynamic Conversations, Powered by Empathy

Polaris 4’s conversational model is engineered to follow a trajectory-aware dialog path, adapting its depth and tone to the patient’s needs. Whether diving deeper into a topic for reassurance or keeping things concise for urgent calls, the system maintains clinical focus while feeling natural and engaging. Adaptive empathy and pacing, paired with purposeful pauses and verbal affirmations, ensure conversations feel warm and human, not robotic.

To elevate voice naturalness, we worked with professional voice actors to capture authentic emotion, from comforting a patient before a procedure to celebrating a recovery milestone. Using advanced voice conversion techniques, we’ve crafted a voice that balances warmth, clarity, and emotional intelligence, making every interaction more relatable and impactful.

These advancements translate to a 21% relative increase in call completion rates over Polaris 3.0, with smoother pacing and clearer phrasing reducing early hang ups and boosting patient trust, as evidenced by higher post-call satisfaction ratings.

Orchestrating Real-World Workflows

Polaris 4 isn’t just about conversation, it’s about integrating seamlessly into healthcare workflows. Our enhanced orchestration features ensure accuracy and reliability in critical tasks:

Scheduling Online Checker: Polaris 4 supports complex scheduling scenarios. It employs offline and online checkers in the course of the conversation to verify appointments in real time against EHR/scheduler systems, reducing booking errors from 0.5% in Polaris 3.0 to 0.01% in Polaris 4.0.
Improved Clinical Documentation: Our offline reconciliation tool, a new addition to the constellation, leverages full conversational context and additional signals to correct errors, boosting item-level form accuracy (e.g., Health Risk Assessments) from 98.5% in Polaris 3.0 to 99.86% in Polaris 4.0.

The Polaris 4 Difference: Safety, Scale, and Humanity

Polaris 4 represents a monumental step forward in healthcare AI, combining cutting edge performance, clinical safety, and improved interaction quality. By aligning voice, timing, and empathy with real-world clinical needs, we’re enabling faster, clearer, and safer patient interactions at an unprecedented scale.

From reducing latency and enhancing speech understanding to achieving near perfect safety and documentation accuracy, Polaris 4 is a trusted partner in healthcare delivery. We’re excited to see how this release empowers our partners in the healthcare industry and patients alike.

For more details on Polaris 4 or to explore its capabilities, visit Hippocratic AI. Stay tuned for real-world examples of Polaris 4 in action, showcasing the unique healthcare skills our AI agents bring to life.

“Polaris 4 is a breakthrough in what truly safe, empathetic, and effective AI can be in healthcare. It’s faster, more natural, and smarter in the moments that matter most, bringing us one step closer to healthcare abundance by expanding access, easing burdens on clinicians, and improving the care experience for everyone.”

Munjal Shah, Co-founder and Chief Executive Officer

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Introducing

Polaris 4: Redefining Patient & AI Interactions for Clinical Excellence

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