Show HN: Boffin – Staff-engineer layer for AI coding agents

Boffin (npm: boffinit) is a staff-engineer control layer for AI coding

agents: it feeds the agent the architectural constraints for the exact file it

is editing and makes it verify the result -- DuckDB case study:

a guided refactor landed at +17 / -17 lines with 2,104 assertions passing.

You ask for a 15-line fix; the agent comes back with a 500-line renovation. Boffin gives the agent the architectural constraints that apply to the file it is about to touch, then makes it verify the result.

It is not another AGENTS.md and not a prompt pack. Those formats usually ship

one static instructions block for the whole repository; Boffin routes only the

constraints relevant to the current edit. Powered by ParselFire Core.

npx boffinit cursor- Not a static repo-wide rules file (AGENTS.md-style one block for everything)

- Not a prompt pack or system-prompt trick

- Not a linter or CI gate -- it acts before and after the edit

- Not a speed tool -- the frame is review-safety

- Selects the constraints relevant to the edit in front of the agent

- Requires verification proportional to the change

- Ships for Cursor, Claude Code, Codex, and OpenCode from one npm package

- Delivers signed portable packs powered by ParselFire Core

The public case studies record these guided refactors on real open-source code:

- DuckDB: +17 / -17; 2,104 assertions across 8 test files passed; distinct continuation and recovery paths were preserved.

- FastAPI: +16 / -33; 49 tests passed; no public API change.

- LangChain: the sync/async boundary was preserved; 4 tests passed.

These are reproducible case studies, not a controlled A/B benchmark.

Boffin requires Node.js 18 or newer.

Run from your project:

npx boffinit cursorRun these inside Claude Code:

/plugin marketplace add MicSm/boffin

/plugin install boffin@boffin

Run these from a terminal:

codex plugin marketplace add MicSm/boffin

codex plugin add boffin@boffinCodex does not trust plugin hooks automatically. Run /hooks once inside Codex

to review and trust Boffin's hooks; until then the plugin's skills work but the

automatic per-session activation stays off.

Run from your project:

npx boffinit opencodeThen open the project in OpenCode. Always-on guidance lands via

opencode.json -> .boffin/AGENTS.md. On demand: /boffin,

/boffin-review, or the boffin / boffin-review skills.

Install details, commands, and troubleshooting: OpenCode delivery.

Want the machinery? Read how ParselFire Core works.

Similar code is not always the same code. Boffin gives the agent a reason to stop before it merges a real special case, blurs a sync/async boundary, moves state away from its owner, or turns a focused task into a tour of the codebase.

- For a focused change, it keeps the requested scope small and asks for the narrowest check that proves the edit.

- For an open-ended refactor or review, it requires a read-only audit first, followed by one verified finding at a time.