Apr 24, 2026·9 min read
Deterministic vs Agentic: The Quiet Architectural Bet Every AI Agent Company Is Making
Two architectures dominate AI agents in 2026. Fat harness has the LLM rethink every step at runtime (Claude Code is the canonical example). Thin harness has the LLM design the pipeline once, then code runs forever. Fat harness wins on novel, open ended, exploratory work. Thin harness is the architecture behind nearly every production agent shipping inside today's SaaS: HubSpot Breeze, Slack summaries, Linear Triage Intelligence, Asana Smart Fields, ClickUp task agents, and WaveAssist. The mistake isn't picking one. It's picking the wrong one for the job.
AIAgentsDeterministicAIAgenticAIWaveAssist