mstar-harness: Instructions file for Claude Code

AGENTS.md

mstar-harness AGENTS.md is an instructions file for Claude Code, Codex, OpenCode from btspoony/mstar-harness. It costs 4,274 tokens per session, scanned A, original, MIT.

Maintenance instructions for Morning Star Harness, a repository that keeps configuration and behavior consistent across several coding tools and command-line packages.

In plain words
What is it for?
Use them when maintaining the OpenCode plugin, command-line tool, host adapters, prompts, or shared runtime and maintenance policies.
Why use it?
They prevent duplicated rules, inconsistent host behavior, and unsafe handling of global settings or secret information.

Instructions file for Claude CodeCodexOpenCode

Written for Claude Code and Codex and OpenCode: Claude Code plugin machinery, but also the file is AGENTS.md. Also seen: mentions subagents; mentions AGENTS.md; mentions Codex.

This is btspoony/mstar-harness's own configuration. It tells Claude Code, Codex and OpenCode how to work on mstar-harness itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything mstar-harness configures →

Reuse

Borrowing it

Nothing to install: this file belongs to btspoony/mstar-harness. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/btspoony/mstar-harness/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/btspoony/mstar-harness

Made for: Claude Code, Codex, OpenCode.

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.

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README.md
[![agentmods](https://agentmods.dev/badge/instructions/btspoony/mstar-harness/agents-md.svg)](https://agentmods.dev/instructions/btspoony/mstar-harness/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/btspoony/mstar-harness/agents-md"><img src="https://agentmods.dev/badge/instructions/btspoony/mstar-harness/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 4,274 This file is loaded in full into every session.
When invoked 4,274 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.04274 $0.04274
Opus 5 $0.02137 $0.02137
Sonnet 5 $0.00855 $0.00855
Haiku 4.5 $0.00427 $0.00427

Measured 4d ago against content hash 3c701452562a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

mstar-harness AGENTS.md 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 4d 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.

AGENTS.md · 257 lines

How it starts

The opening of the file, as written. The whole thing — 257 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Morning Star Harness Maintenance Guide

This repository is maintained as a harness/configuration project, not an application repo. Use this document as the primary maintenance contract for contributors and agents.

Scope

  • Default intent in this workspace: maintain Morning Star harness behavior, docs, and host adapters.
  • Repository layout uses a monorepo-style split: packages/opencode for the publishable OpenCode plugin (@mstar-harness/opencode), packages/cli (@mstar-harness/cli) for the standalone CLI.
  • Do not treat this repo like a product feature/codebase task unless explicitly requested.
  • Runtime execution rules for users/agents live in mstar-* skills; this file defines maintenance behavior.

Maintenance Goals

  • Keep one coherent harness behavior across hosts.
  • Keep prompts/rules minimal, explicit, and non-duplicated.
  • Prefer stable defaults and small, reviewable changes.
  • Preserve user safety boundaries for global config and secrets.

Core Rules

  • Single source by topic: keep each rule in one authoritative place; avoid copy-paste rule drift.
  • Execution vs maintenance split:
    • Skills/role prompts describe runtime behavior.
    • AGENTS.md describes repository maintenance policy.
  • Surgical edits: only change what the task requires; avoid opportunistic refactors.
  • Read before edit: inspect current content before patching; verify after patching.
  • Worktree-only development: all feature/plan development happens in git worktrees under .worktrees/; the primary checkout stays on main at all times. Never check out a working branch in the primary checkout — skills/commands may be symlinked into this directory, so a feature branch checked out here would break linked consumers. Local main receives no direct feature commits (changes land via PRs/merges).
  • README = developer consumer docs (README.md / README_CN.md):
    • Audience is developers who install and run the harness — not a concept tutorial.
    • Prefer commands, tables, and links. Do not write chatty “How to use” prose.
    • A short curated value-prop bullet list at the top is allowed; keep it to a few selling points, not a marketing essay.
    • Keep the shortest executable path: Install → Use (without iteration vs with iteration) → Workflow diagram → Roles/skills tables.
    • Put narrative, deep install, and host quirks in INSTALL.md, docs/, or mstar-* skills — not in the README body.
    • Edit both language files together when README content changes.
    • Bilingual minimal updates: for paired docs (README.md/README_CN.md, packages/dsh README triplets), apply the minimal counterpart edit — never re-translate a document to apply an update — and re-record pairing hashes (git hash-object) in the same change set.

Read the full file on GitHub · 257 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. 4d ago Changed · +4 lines · +101 tokens per session 3c701452562a
  2. 8d ago First seen · 253 lines · 4,173 tokens per session scan A 6397316781b7

Subscribe to this mod's changes

mstar-harness AGENTS.md is an instructions file published in the GitHub repository btspoony/mstar-harness (58 stars, last pushed yesterday), licensed MIT. It adds 4,274 tokens to every session, about $0.0214 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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