the same-ish prompt gives you a different agent plan depending on the run and i still don't have a great answer for testing that
Summary
The author discusses challenges in testing LLM-based agent pipelines where outputs vary with similar prompts, advocating for property-based checks over exact matches to handle non-deterministic outputs.
Similar Articles
Same model, same prompt, 4 different agents
Explores how different agent architectures yield varying outputs from the same underlying model and prompt, highlighting the impact of agent design on LLM behavior.
Same agent, same prompt, different runs. Which output do you ship?
The author observes that running the same task with Claude Code across different sessions yields varying decision patterns, making it hard to choose outputs that are safe to ship, and highlights the lack of tooling for evaluating agent decision profiles.
Your LLM prompt has 200 lines. Do you actually know if the agent follows any of them?
This article discusses the challenges of evaluating and monitoring LLM-based agents in production, covering offline evals, prompt engineering pitfalls, observability tools, review queues, labeling, clustering, topic classification, and cost-effective layering of human review, LLM-as-a-judge, and small classifiers.
The longer an agent runs, the less I care about the prompt
The author reflects on how long-running AI agents encounter failures unrelated to the initial prompt, arguing that environment design (tools, docs, validation, architecture rules) matters more. They discuss concepts like harness engineering, keeping AGENTS.md small, using linters, and evaluator agents, while noting the cost trade-offs.
Your LLM Doesn’t Need Better Prompts — It Needs an Agent Harness
An article discusses the need for Agent Harness Engineering—structured systems with tool validation, context management, guardrails, telemetry, and verification loops—to make LLM agents reliable in production, arguing that better prompts alone are insufficient.