Strands Agents SDK, AWS's open-source framework for model-driven AI agents, adds Strands Steering โ Python handlers that intercept execution before tool calls and after model responses. Instead of cramming behavioral rules into prompts that models routinely ignore, handlers inspect the agent's real-time tool call ledger and return Proceed or Guide signals with targeted correction. Handlers are plain Python โ deterministic, unit testable, and fully reproducible. For nuanced checks like tone enforcement, they can call an LLM judge.
Across 600 evaluation runs, steering achieved 100% accuracy vs. 82.5% for prompt engineering, 80.8% for graph workflows, and 99.8% for SOPs โ while using 66% fewer input tokens than the SOP approach.
Add handlers as plugins to any Strands agent to enforce workflow ordering, parameter constraints, and tone โ no prompt edits needed when agent behavior drifts.