Symphony: what we've been building - and what's coming next

In January 2025 we introduced Symphony - our flagship clinical-grade AI model, purpose-built for healthcare. Since then, we've been heads down: training, shipping, and stress-testing Symphony across real clinical environments in multiple markets.

Ahead of a major product update next week, here is where things stand today.

A year of building Symphony

Symphony is our flagship model powering the full breadth of Corti's AI capabilities - from clinical speech recognition and documentation generation to medical coding intelligence and agentic workflows. Across these, the same core architecture applies: domain-specific capabilities, trained on real clinical data, coordinated through an orchestration layer built for the compliance and complexity of healthcare.

A few highlights from the past year

• Clinical-grade speech-to-text layer. Premier-tier speech-to-text models shipped for English, German, French, and Danish - each validated against 150,000+ medical terms and scaled in production clinical environments. Dutch, Norwegian, Hungarian, Arabic, and Swiss German followed, with dictation formatting now supported across core languages
• The Symphony reasoning engine. FactsR, our real-time clinical reasoning engine, went live - extracting and fact-checking clinical information as conversations unfold, giving clinicians verified facts rather than hallucinated paragraphs. It now runs asynchronously across complex LLM pipelines and as a real-time reasoning engine for synchronous flows built on Symphony. 
• Guardrail layer powering compliant orchestration. Re-architected documentation guardrails that identify hallucinations at the sentence level and apply targeted, auditable corrections - format-preserving and precise
• The interpretability layer. GIM, a benchmark-leading method for mechanistic interpretability, giving us better tools to understand what's actually happening inside AI models
• The agent builder and orchestration layer. The Corti Agentic Framework, enabling healthcare organisations to build and configure purpose-built AI agents for workflows like medication reconciliation and clinical quality assurance

Why Symphony

When we first introduced our model family in January 2025, we gave each model tier its own name: Solo for fast and accurate audio transcription, Ensemble for documentation, and Symphony for real-time clinical support with full reasoning capabilities. The logic was sound - different models optimised for different tasks, named accordingly.

But we've shipped a lot since then. The platform today is fundamentally more capable than it was twelve months ago, and the boundaries between those original tiers blurred as the technology matured. When you call a Corti endpoint today, you're not selecting a single model - you're invoking an orchestration layer that routes your request to the right combination of capabilities depending on the task. That's the same architectural shift the major model providers have made: when you call GPT or Claude, you're increasingly calling a routing layer, not a single model. The individual tier names simply stopped reflecting how the technology works.

So we're consolidating. Going forward, Symphony is our core model, versioned over time, covering every AI capability in our stack. When we ship major updates, they'll be Symphony releases. When you call a Corti endpoint, you're calling Symphony.

When a lab moves this fast, the language has to keep up. Symphony is how we make sure it does - for our customers, our partners, and ourselves.

What's under the hood

Symphony combines domain-specific capabilities trained and validated on real clinical data, an orchestration layer that routes tasks to the right intelligence, and validation against real-world patient outcomes. We build and layer years of healthcare-specific IP: proprietary training data, clinical reasoning engines, and purpose-built pipelines for regulated and compliance-heavy workflows. That combination is the product of nine years of peer-reviewed research - and of building from inside the clinical environment, not reaching in from the outside.

April 1: A major Symphony update

Next week, we're shipping a significant new capability within Symphony - one that addresses one of the most complex, costly, and underserved workflows in healthcare. We'll have a lot more to say on April 1.

Stay tuned!