Retrace.

Retrace: The Execution Replay Engine for AI Agents

Retrace transforms how engineering teams build reliable AI agents by turning every production failure into a reproducible regression test. With a single decorator, you capture complete execution traces, fork from exact failure points, and prove your fixes work before shipping—bringing CI/CD rigor to agent behavior that traditional observability tools simply cannot match.

Product Highlights

• Execution Replay: Re-run any recorded agent trace and fork from the exact step where failure occurred to isolate root causes instantly.
• Prove-the-Fix Verification: Modify prompts, tools, or models and re-run against the failed execution to get a definitive verdict before deployment.
• Runtime Guardrails: Enforce cost budgets, loop limits, and step thresholds in real-time—halt runaway agents before they generate surprise cloud bills.
• Framework-Agnostic Instrumentation: One decorator integrates with OpenAI, Anthropic, Gemini, LangChain, CrewAI, LlamaIndex, and any Python or TypeScript agent.
• CI Regression Gates: Automatically convert production failures into eval tests that block PRs when behavior regresses, not just when code breaks.

Use Cases

• Incident Root Cause Analysis: When an agent fails in production, fork from the symptom step, trace the actual cause (like a 50× batch size change), and verify the fix resolves it.
• Prompt & Model Regression Testing: Ship prompt edits and model upgrades with confidence—eval gates compare new runs against golden baselines to catch silent behavioral drift.
• Multi-Agent Debugging: Visualize agent topology, session flows, and memory state across complex agent systems where traditional logs leave you blind.
• Cost Control & Safety: Prevent runaway loops and budget blowouts with circuit breakers that halt execution when thresholds cross—enforced before the damage occurs.

Target Audience

Retrace serves AI engineers, platform teams, and engineering leaders building production-grade agent systems who need more than dashboards—they need interactive debugging, behavioral CI gates, and runtime enforcement that prevents failures rather than just documenting them.