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AI · August 20, 2026

AgentDiff

Trajectory regression testing for AI agents

AgentDiff launched on August 20, 2026 with 4 votes, #2,153 of 23,274 launches that month and more than 75% of that year's launches.

What it does

Traditional evals test outputs, missing when agents loop on tools or burn 50% more tokens. AgentDiff fixes this by recording agent runs as DAGs and diffing execution trajectories against golden baselines directly in CI. It catches tool loops, cost spikes, and latency regressions before merge evaluating how the model arrived at the answer, not just what it returned. Framework-agnostic with adapters for OpenAI Agents, Langfuse, LangSmith, and OpenInference.

AgentDiff compares agent execution traces as DAGs in CI/CD - automatically detecting trajectory drift, redundant tool loops, and cost regressions.

Your agent returned the right answer, but took 5 extra steps and burned 3× the tokens. AgentDiff catches silent tool loops, cost surges, and execution drift in CI before your PR lands in production. Traditional assertions only check if the final output string matched. They are blind to execution drift — missing recursive tool loops, unverified prompt detours, and 3× cost surges before code merges. The agent still delivered the expected summary, so standard assertion tests pass easily in CI. Behind the scenes, a prompt tweak caused the agent to loop 3 times over the customer database. AgentDiff detects the step surge in milliseconds and fails the PR before it ever costs you real money. No…from agentdiff.lostmartian.in

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