cairn-ground-state

cairn-ground-state is a cursor rule for coding agents from isaacriehm/cairn. It costs 170 tokens per session, scanned A, original, MIT.

A set of working rules for Cairn, a tool that tracks a project's current state, decisions, and tasks.

In plain words
What is it for?
It helps decide whether a structural change is in scope, reuse or extend existing UI components, record important decisions, and start substantial work with the current project direction.
Why use it?
It reduces guesswork during code changes by checking the project's scope and existing choices before changing its structure or interface.

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/isaacriehm/cairn/cairn-ground-state
Clone the repo
git clone --depth 1 https://github.com/isaacriehm/cairn

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for cairn-ground-state

README.md
[![agentmods](https://agentmods.dev/badge/rules/isaacriehm/cairn/cairn-ground-state.svg)](https://agentmods.dev/rules/isaacriehm/cairn/cairn-ground-state)
Your own site
<a href="https://agentmods.dev/rules/isaacriehm/cairn/cairn-ground-state"><img src="https://agentmods.dev/badge/rules/isaacriehm/cairn/cairn-ground-state.svg" alt="Measured on agentmods" height="20"></a>
Per session 170 This file is loaded in full into every session.
When invoked 170 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 $0.00170 $0.00170
Opus 5 $0.00085 $0.00085
Sonnet 5 $0.00034 $0.00034
Haiku 4.5 $0.00017 $0.00017

Measured 5d ago against content hash ab29a0c9823e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cairn-ground-state 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 5d 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.

packages/cairn-plugin/rules/cairn-ground-state.mdc · 17 lines

What it actually says

This project uses Cairn for ground-state management. If .cairn/ exists at the repo root:

  • Never invent architectural patterns; check cairn_in_scope({path_globs}) before making structural changes.
  • Before UI work, call cairn_components_in_scope({path_globs}) — USE existing components before EXTENDING, EXTEND before CREATE.
  • Record non-obvious choices with cairn_record_decision.
  • Use the cairn-direction skill (or /cairn-direction command) for any code-change task — Cursor has no per-prompt working-header hook; invoke direction manually when starting substantive work.
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. 5d ago First seen · 17 lines · 170 tokens per session scan A ab29a0c9823e

Subscribe to this mod's changes

cairn-ground-state is a cursor rule published in the GitHub repository isaacriehm/cairn (6 stars, last pushed 1mo ago), licensed MIT. It adds 170 tokens to every session, about $0.0009 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.