[Linkpost] Prefixing names with 'secure_' makes agents write more secure code

The graphs are interactive and don't translate well to inline, so the full writeup with figures is in the link.We gave coding agents a three-step synthesis task: build a document management API, then extend it twice. Across conditions we varied the prefix attached to the four initial function names (secure_, safe_, energetic_, lazy_, unsafe_, control). The downstream steps were identical, prefix-neutral prompts. Each task was handed to a fresh agent, with only the codebase as context to influence it. Six conditions, three replicates each, 54 tasks total.In all three secure_ runs, and none of the other fifteen, the agent added password fields and hashed them with bcrypt, despite no mention of authentication anywhere in the task. A simple prepend was enough to reliably reorganize what the agent took the project to be.Every prefix seeded a distinct conceptual world that persisted across independently prompted steps: safe_ invented a custom error-handling hierarchy; secure_ was far more defensive everywhere, not just around passwords; energetic_ produced async workers and many more decorators.We also saw the prefixes propagate, an agent sees secure_create_user and coins secure_upload_document on its own. There were domain boundaries where new, structurally distinct sections of the project did not inherit the prefix, except energetic_, which spread into the new domain in 2/3 of replicates. Meanwhile cyclomatic complexity stayed flat; the prefixes changed what was built, not how complex each piece was.The prefix experiment was motivated by a pilot observation: TF-IDF identifier distributions in agent-generated repos stabilize early and strongly. Similarity-to-HEAD necessarily rises toward 1 as a repo nears its final commit, that said Gas Town jumped from 8% to 81% similarity-to-HEAD in a single commit and OpenClaw's vocabulary changes <1% over 600k lines of code, with refactors barely denting the curve. Human-generated repos, by contrast, are bumpy and rise roughly linear