Senior Ai Software Engineer

Senior Software AI Engineer — Agentic PlatformsFull-Time, Permanent | Downtown Toronto | HybridOur client, a global enterprise, is building an internal AI platform — a multi-tenant, model-agnostic environment spanning a web app, a desktop agent client, an AI App Store, and a skills/tool ecosystem over the company's knowledge.
They're looking for a Senior AI Engineer to help design and build the agent infrastructure at the core of it: orchestration engines, the desktop agent harness, tool/skill registries, and the policy layers that make it all safe to run at enterprise scale.
What you'll do
Build and extend multi-agent orchestration (LangGraph, Microsoft Agent Framework, Deep Agents) — stateful graphs, checkpointing, sub-agents, human-in-the-loop, long-running execution.
Work directly with frontier LLM SDKs at the agent-loop level (Anthropic, OpenAI, Google) — not just chat completions.
Own the model-agnostic routing layer: provider routing, cost/token accounting, graceful degradation as models churn.
Build MCP integration, sandboxing/process isolation, and a permission system (ALLOW/ASK/DENY) enforced across runtimes.
Build retrieval, grounding, and citation pipelines that hold up in production.
Build eval infrastructure — regression gates, tracing, and diagnosability for agent failures.
What we need
7+ years building production software, with recent, substantial work on LLM-based systems used by real users.
Strong TypeScript
(Node.Js, async, strict typing) and working proficiency in Python (FastAPI, Pydantic).
Production depth in LangGraph, Microsoft Agent Framework, or Deep Agents.
Direct experience with at least one frontier provider SDK at the agent-loop level.
Hands-on with tool calling, MCP (or comparable), streaming (SSE/WebSocket), structured output.
Nice to have
Google ADK, Semantic Kernel, CrewAI, LlamaIndex, AutoGen, Pydantic AI, Mastra.
Sandboxing/isolation experience (gVisor, nsjail, Firecracker, Seatbelt, Bubblewrap).
Electron/desktop app engineering, vector search, regulated-industry experience (insurance, banking, financial services).
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