core

A set of mandatory project rules for the harness-score monorepo, a repository containing several related packages and documentation.

In plain words
What is it for?
Use it when changing scanner checks, guide documentation, check IDs, package dependencies, or scoring behavior.
Why use it?
It prevents changes from breaking deterministic scanning, public check identifiers, dependency limits, documentation translations, or the required score.

Cursor rule for Cursor

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/paladini/harness-score/core
Clone the repo
git clone --depth 1 https://github.com/paladini/harness-score

Made for: Cursor.

Per session 245 This file is loaded in full into every session.
When invoked 245 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 $0.00245 $0.00245
Opus 5 $0.00122 $0.00122
Sonnet 5 $0.00049 $0.00049
Haiku 4.5 $0.00024 $0.00024

Measured 2d ago against content hash 7f0939d8b912, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

core 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.

.cursor/rules/core.mdc · 19 lines

What it actually says

  • The scanner is deterministic by contract: no model calls, no network, no time-dependent output. If a proposed check needs judgment, it does not belong in the CLI — it belongs in the guide as advice.
  • packages/cli has zero runtime dependencies. Do not add one.
  • Check changes touch three files together: packages/cli/src/score.ts, docs/guide/maturity-model.md, docs/guide/measure-and-improve.md — enforced in CI by docs.test.ts and maturity-sync.test.ts.
  • Guide edits must keep all five locales in sync — see .cursor/rules/docs-i18n-parity.mdc and docs.test.ts (file set + anchor parity).
  • Check IDs are stable public API (they are documentation anchors and appear in users' CI logs). Never renumber, reuse, or delete an ID — deprecate by making the check always-pass if truly needed.
  • This repository must keep scoring L4 on npm run scan.
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 · 19 lines · 245 tokens per session scan A 7f0939d8b912

Subscribe to this mod's changes

core is a cursor rule published in the GitHub repository paladini/harness-score (199 stars, last pushed 4d ago), licensed MIT. It adds 245 tokens to every session, about $0.0012 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 2026-08-30.