Context Engineering for Production Agentic Systems, or Why Pipeline Beats PromptThis is Part 1 of a three-part field manual on engineering production agentic systems. Part 1 takes context engineering. Part 2 takes guardrails. Part 3 takes human-in-the-loop topology. The conviction underneath all three: production agentic systems are won on these three architectural disciplines — not on model choice. The Opening ClaimThe first time a production agent fails because of context-window collapse, the team’s instinct is to switch to a bigger model. The agent’s reasoning gets noisy at turn nine, the most important piece of context ends up buried in the middle of the prompt, the output comes back confident and structurally wrong. The team upgrades. Six weeks later, the same failure recurs at turn fourteen.