loop-northstar

loop-northstar is a skill for Claude Code, Codex from rome-os/rome. It costs 27 tokens per session (894 once invoked), scanned A, original, MIT.

An interactive session for writing or revising a repository document that describes the desired end state of an area of code.

In plain words
What is it for?
Use it to create or refine documents in docs/northstars/ and divide the agreed target into repository milestones.
Why use it?
It turns an unclear target into agreed, checkable statements that can later be compared with the codebase.

Skill for Claude CodeCodex

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 skills/rome-os/rome/loop-northstar
Any agent
npx skills add rome-os/rome --skill loop-northstar
Clone the repo
git clone --depth 1 https://github.com/rome-os/rome

Made for: Claude Code, Codex.

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 loop-northstar

README.md
[![agentmods](https://agentmods.dev/badge/skills/rome-os/rome/loop-northstar.svg)](https://agentmods.dev/skills/rome-os/rome/loop-northstar)
Your own site
<a href="https://agentmods.dev/skills/rome-os/rome/loop-northstar"><img src="https://agentmods.dev/badge/skills/rome-os/rome/loop-northstar.svg" alt="Measured on agentmods" height="20"></a>
Per session 27 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 894 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00027 $0.00894
Opus 5 $0.00014 $0.00447
Sonnet 5 $0.00005 $0.00179
Haiku 4.5 $0.00003 $0.00089

Measured yesterday against content hash 142a02c441ad, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

loop-northstar 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 yesterday.

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.

.claude/skills/loop-northstar/SKILL.md · 53 lines

How it starts

The opening of the file, as written. The whole thing — 53 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Loop: north star

Goal end-state: the ideal state of the target area is written down and agreed — as a doc PR, and when the session slices it, as approved repository milestones.

This is the interactive half of the reconciliation loop. The autonomous half (loop-reconcile) computes the gap between these artifacts and the codebase and files work issues. This session files no work issues.

The ideal-state doc

The doc lives in docs/northstars/, one file per area, named for the area it describes. It describes the ideal present — what should be true. Never how to get there, and never what used to be. Prose follows WRITING.md.

The body takes whatever form fits the subject — contract tables, flow descriptions, diagrams, examples — with one required section: Statements, a bullet list of checkable claims. Only the Statements section has authority. loop-reconcile computes the gap against it, and everything else is illustration.

Admission rules for every statement:

  • Declarative present tense. No "currently", no "we will", no "migrate from", no milestone names.
  • Checkable: an agent can verify compliance by reading the code.
  • Open: more than one implementation can satisfy it. The test: the statement stands without naming a file, function, or type. A statement only one implementation satisfies is code transcribed into prose.
  • A statement asserting that something is answered one way, or once, names the question it answers. Compliance turns on which reads count as the same question, so a uniqueness claim without its question cannot be checked.

Content that never enters the doc:

  • Milestones. They go to the repository's milestone list and die there.
  • Rationale. It goes to an ADR.
  • Migration policy. It lives in loop-reconcile.

Milestones

A milestone is an intermediate ideal state. Its description is a Statements list — typically a subset or a weakened version of the north star's statements — plus optional notes. The same admission rules apply: what, never how.

Read the full file on GitHub · 53 lines

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. yesterday Changed · +2 lines 142a02c441ad
  2. 5d ago First seen · 51 lines · 27 tokens per session scan A a3710dc33a3e

Subscribe to this mod's changes

loop-northstar is a skill published in the GitHub repository rome-os/rome (451 stars, last pushed yesterday), licensed MIT. It adds 27 tokens to every session and 894 once invoked, about $0.0001 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.

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