Who Coined What: The Origins of the Agent-Engineering Terms

This article is part of a series on AI coding agents' "XXX engineering" terms. Its thesis: each new term (prompt, context, harness, loop, graph) adds a ring around the last one instead of replacing it, and each article asks where the human sits. Find the other articles in the series:

1. "AI Coding Agents: From Writing Prompts to Designing Systems"
2. "After loops: is graph engineering the next ring?" [coming soon, working title]
3. "Harness engineering, or agent = model + harness" [coming soon, working title]
4. "Loop engineering, or sit on the loop, not in it" [coming soon, working title]
5. "Who Coined What: The Origins of the Agent-Engineering Terms" (this article)

The five terms, checked

We checked who coined the five terms this series follows: prompt, context, harness, loop and graph engineering. Each fact below comes from a primary source.

No surprise: the person who coined the word is never the one who made it famous. The gap between the two runs from six days to more than two years.

coined, then made famous · five terms, 2020–2026

Prompt engineering (2020 → 2022)

• First use: summer 2020, around Gwern Branwen's GPT-3 essay (June 19, 2020), where Gwern wrote "prompt programming". The earliest dated "prompt engineering" we found is Andrej Karpathy's, on X, July 5, 2020: sharing Gwern's experiments, he listed "prompt engineering subtleties" among the highlights. Merriam-Webster dates the first known use to 2020.
• Made famous: ChatGPT's launch, November 30, 2022.
• Gap: 2.4 years.
• Verdict: no single coiner can be named. The word grew out of Gwern's GPT-3 experiments, and its earliest dated use is Karpathy's, describing them.

Context engineering (April → June 2025)

• First use: Dex Horthy (CEO, HumanLayer), in 12-Factor Agents, published on April 15, 2025 (the term is already in his drafts from March 31).
• Made famous: Tobi Lütke (June 19, 2025), then Andrej Karpathy (June 25, 2025).
• Gap: 2 months.
• Verdict: Horthy coined it.

Harness engineering (February 2026, contested)

• First use: Mitchell Hashimoto, My AI Adoption Journey, February 5, 2026. He writes that he has taken to calling it "harness engineering" and would switch if a name already existed.
• Made famous: OpenAI (Ryan Lopopolo), Harness engineering, February 11, 2026.
• Gap: 6 days.
• Contested: Addy Osmani credits Vivek Trivedy (LangChain). Trivedy's posts came later (February 17 and March 10, 2026), and neither claims the word.
• Verdict: the earliest use is Hashimoto's. The formula Agent = Model + Harness is Trivedy's (March 10, 2026), and it is the title of the second post in the series.

Loop engineering (March → June 2026)

• First use: Franziska Hinkelmann on X, March 8, 2026: "The real evolution is Loop Engineering."
• Made famous: Boris Cherny (WorkOS interview, June 2, 2026), Peter Steinberger (X, June 7, 2026) and Addy Osmani's essay Loop Engineering (June 7, 2026).
• Gap: 3 months.
• Contested: for most readers, Osmani's essay named and structured the practice. He credits Steinberger and Cherny, does not claim the word and does not mention Hinkelmann.
• Verdict: Hinkelmann used the word first. Her post also answers this series' question:

"The human shouldn't be the editor. The human should be the architect of the loop."

Graph engineering (2024 → July 2026)

• First use: Itamar Friedman (CodiumAI, now Qodo). His AlphaCodium paper (January 16, 2024) is titled From Prompt Engineering to Flow Engineering. On X, February 29, 2024, he added "graph" as an alias (quoted below).
• Ladder posted early: Mike (@michaelmasson55) on X, July 11, 2026: prompt, context, harness, loop, then "next is: graph engineering". 87 views by October.
• Made famous: Peter Steinberger on X, July 18, 2026: "Are we still talking loops or did we shift to graphs yet?" The phrase "graph engineering" is not in his post. Four and a half hours later, Hamel Husain published Loop Engineering Is Dead. Enter Graph Engineering.
• Gap: 2.4 years.
• Verdict: Friedman coined it, as an alias of "flow engineering".

"When building real world AI empowered systems, we see a shift from prompt engineering to flow (/graph) engineering."

What it means

The words are older than their fame, like the practices in the first post: each waited until its ring became the main bottleneck and someone with a large audience said it. When the next buzzword arrives with a famous name attached, check who said it first, then ask: where does the human come in?

Sources

• Gwern Branwen, GPT-3 Creative Fiction, June 19, 2020 (uses "prompt programming")
• Andrej Karpathy, post on X, July 5, 2020
• Hacker News comment crediting Gwern with "prompt engineering", July 31, 2020
• Merriam-Webster, prompt engineering, first known use 2020
• Dex Horthy, 12-Factor Agents, commit history from March 30, 2025; term first in commit bc4fa56, March 31, 2025
• Dex Horthy, 12-factor Agents: Patterns of reliable LLM applications, Hacker News launch, April 15, 2025
• Tobi Lütke, post on X, June 19, 2025
• Andrej Karpathy, post on X, June 25, 2025
• The Pragmatic Engineer, Context engineering with Dex Horthy, July 15, 2026
• Mitchell Hashimoto, My AI Adoption Journey, February 5, 2026
• OpenAI (Ryan Lopopolo), Harness engineering: leveraging Codex in an agent-first world, February 11, 2026
• Vivek Trivedy, Improving Deep Agents with Harness Engineering, February 17, 2026
• Vivek Trivedy, The Anatomy of an Agent Harness, March 10, 2026
• Addy Osmani, Agent Harness Engineering, O'Reilly Radar, May 15, 2026
• Boris Cherny, WorkOS interview, June 2, 2026
• Peter Steinberger, post on X, June 7, 2026
• Addy Osmani, Loop Engineering, June 7, 2026
• Ridnik, Kredo, Friedman, Code Generation with AlphaCodium: From Prompt Engineering to Flow Engineering, arXiv, January 16, 2024
• Itamar Friedman, post on X, February 29, 2024
• Franziska Hinkelmann, post on X, March 8, 2026
• Mike (@michaelmasson55), post on X, July 11, 2026
• Peter Steinberger, post on X, July 18, 2026
• Hamel Husain, Loop Engineering Is Dead. Enter Graph Engineering, X Article, July 18, 2026