Code-Writing Agents in 2026: Execution-Based Evaluation Beats Everything Else
Why LLM-as-judge is the wrong tool for code agents — and how to build an execution-based eval pipeline that actually catches broken code.
Agentic AI, LLM engineering, and the models behind modern automation — multi-agent systems, LLM evaluation and comparisons, RAG, fine-tuning, AI infrastructure, security, and production AI engineering.
From the blog
Why LLM-as-judge is the wrong tool for code agents — and how to build an execution-based eval pipeline that actually catches broken code.
Run offline evals as a CI gate. GitHub Actions wiring, threshold gates, LangSmith Experiments, and how to block merges on agent regression — with real YAML.
Eval scores alone mislead. Here is how we build a Pareto view across cost, latency, and quality so agent releases ship on signal, not vibes.
Memory is supposed to make agents better — but does it? Build a memory eval pipeline that measures recall, precision, contradiction rate, and the freshness/staleness tradeoff.
A 'did the agent answer correctly?' pass/fail hides broken tool calls, wasted tokens, and silent retries. Here is how to evaluate intermediate steps.
Final-answer accuracy hides broken reasoning. Build an eval pipeline that scores the reasoning trace itself — coherence, faithfulness to tools, dead-end detection.
A principal engineer's playbook for curating, versioning, and growing a golden dataset for an agent — from production trace mining to annotation queues in LangSmith.
When reasoning models actually help inside an agent loop — and when they're an expensive mistake. Architecture patterns, code, and the cost/quality tradeoffs that matter.
Stop the agent BEFORE it does the wrong thing. How to wire input and output guardrails in the OpenAI Agents SDK with cheap classifiers and an eval suite that proves they work.