Azure Foundry Model Router adds Grok 4.3; Cosmos DB lands LangChain/LangGraph integration

Azure Foundry's Model Router — Microsoft's multi-model routing layer — added Grok 4.3 alongside its existing OpenAI, Mistral, and Meta selections. The addition is notable because it normalizes xAI on a hyperscaler that's historically been OpenAI-first, and because it lands the same week Microsoft cut most direct Claude Code licenses. Foundry now offers a genuinely model-agnostic surface, even if the recommended path remains OpenAI.

The Cosmos DB LangChain and LangGraph integration is the bigger developer story. Native bindings let agent apps use Cosmos DB as both a vector store and a stateful checkpoint backend for LangGraph workflows — eliminating the glue code that's been the main complaint from teams building agent apps on Azure. Pricing rides on existing Cosmos consumption, which is friendlier than per-request vector DBs.

Infrastructure side: AKS now ships AppInsight auto-instrumentation for AI workloads (request/token telemetry without code changes), and Azure Linux 4.0 GA brings updated kernels and container runtimes. Together these tighten the operational story for Azure-hosted agents.

Competitively, this is Microsoft signaling that Foundry — not the OpenAI-only Azure surface — is the strategic developer entry point, and that Cosmos DB is being repositioned as the default agent state store. Watch next: a managed LangGraph runtime announcement and Foundry's pricing posture against AWS Bedrock AgentCore.