breakthrough-loop

A set of research rules built around a repeatable testing cycle and a strict evaluation harness.

In plain words
What is it for?
Planning research experiments, comparing method variants, reproducing published results, and recording verified gains.
Why use it?
It helps prevent false improvements by requiring baselines, separated tuning and evaluation data, sanity checks, and confirmation on held-out data.

Cursor rule

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/guocheng24/breakthrough-harness/breakthrough-loop
Clone the repo
git clone --depth 1 https://github.com/GuoCheng24/breakthrough-harness
Per session 400 This file is loaded in full into every session.
When invoked 400 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00400 $0.00400
Opus 5 $0.00200 $0.00200
Sonnet 5 $0.00080 $0.00080
Haiku 4.5 $0.00040 $0.00040

Measured 2d ago against content hash 1e328da1e04d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

breakthrough-loop scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

adapters/cursor/breakthrough-loop.mdc · 33 lines

What it actually says

Breakthrough-loop discipline (drop into .cursor/rules/)

Full methodology: https://github.com/GuoCheng24/breakthrough-harness

When running research experiments in this project:

  • Triage the target first: cheap scoring function + existing groundwork + externally recognisable win + an oracle-ceiling/trivial-baseline gap worth mining (measure before round 1). Any missing -> flag it and stop.
  • Build the harness before the method: single evaluation entry point; null models scored first and pinned to the floor; metric conventions pinned (double-report if the published one differs); calibration and evaluation data physically separated - tuning touches calibration only.
  • Reproduce a published baseline number before trusting ours; an unmatched baseline means the recipe has unread layers (optimizer, loss, metric convention, operator).
  • Loop: 10-30 variants/round each with a one-line reason it might win; sanity-check before entry; executors only call the entry point, never write method code inline; select on calibration; confirm top-k held-out. Unreproduced gains do not exist; report confirmations with a paired error bar, budget held-out accesses. Persist numbers to disk, then write.
  • Claim polarity: the main sentence of any result is constructive ("we propose X, it solves Y, number Z"); audits and negatives are supporting material, never the headline.
  • Verify every new guard by deliberately breaking what it watches, and confirm it fails for the right reason.
  • Stop conditions: a well-scoring null model or any firing anti-cheat check freezes all conclusions until the harness is repaired; when candidates stop carrying new reasons, record the ceiling number and escalate to a more ambitious target class instead of continuing to sweep.
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 33 lines · 400 tokens per session scan A 1e328da1e04d

Subscribe to this mod's changes

breakthrough-loop is a cursor rule published in the GitHub repository GuoCheng24/breakthrough-harness (1 stars, last pushed 2d ago), licensed MIT. It adds 400 tokens to every session, about $0.0020 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.