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rubber-duck AGENTS.md

rubber-duck AGENTS.md is an instructions file for Codex, OpenCode from sprngr/rubber-duck. It costs 1,513 tokens per session, scanned A, original, MIT.

Repository instructions for Rubber Duck, a Socratic AI assistant project focused on evidence-based decisions and carefully limited changes.

In plain words
What is it for?
Use them when developing Rubber Duck, verifying generated artifacts, running validation, or installing it for a supported coding client.
Why use it?
They explain the project layout and the commands for building, checking, validating, and installing its generated files.

Instructions file for CodexOpenCode

not rated 8 yesterday A scan 1,513 tokens original MIT
View the source file sprngr/rubber-duck
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 instructions/sprngr/rubber-duck/agents-md
Clone the repo
git clone --depth 1 https://github.com/sprngr/rubber-duck

Made for: 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.

agentmods badge for rubber-duck AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/sprngr/rubber-duck/agents-md.svg)](https://agentmods.dev/instructions/sprngr/rubber-duck/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/sprngr/rubber-duck/agents-md"><img src="https://agentmods.dev/badge/instructions/sprngr/rubber-duck/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 1,513 This file is loaded in full into every session.
When invoked 1,513 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 5.1 $0.01513 $0.01513
Opus 5 $0.00757 $0.00757
Sonnet 5 $0.00303 $0.00303
Haiku 4.5 $0.00151 $0.00151

Measured 5d ago against content hash a5e36795042d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

rubber-duck 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 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.

AGENTS.md · 156 lines

How it starts

The opening of the file, as written. The whole thing — 156 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

What this is

Rubber Duck is a Socratic AI assistant project. It focuses on decision quality, evidence-first reasoning, and bounded safe changes.
This repository contains source prompts, assembled skills, generated harness artifacts, installers, validation fixtures, and policy docs.

Quick Start (5 minutes)

  1. Verify tools: bash, pwsh, python3, node/npx, jq, make
  2. Build generated artifacts:
    • make build
  3. Verify generated artifacts are clean:
    • make check
  4. Run validation suite:
    • make validation
  5. Install locally (example):
    • Bash: ./scripts/rubber-duck.sh install --opencode
    • PowerShell: ./scripts/rubber-duck.ps1 install -OpenCode

Layout

  • src/ - source-of-truth for agents, skills, and shared snippets
    • src/install/scripts/ - sync wrapper templates
    • src/install/templates/ - manifest template
  • skills/ - built skill artifacts generated from src/skills/*
  • dist/ - built harness artifacts generated from src/agents/*
    • dist/scripts/ - generated sync wrapper scripts
    • dist/templates/ - generated manifest template
  • scripts/ - build, check, and installer scripts (rubber-duck.sh, rubber-duck.ps1)
  • docs/ - architecture and supporting documentation
  • validation/ - prompt validation suite, fixtures, and runner
  • tests/ - fixture-style behavior tests and expected outputs
  • .github/ - tracked CI/workflow config
  • .agents/, .claude/, .opencode/ - local harness install targets (untracked, populated by installers)
  • build/ - assembly/check rules

Tooling and Runtimes

  • Bash (Linux/macOS/CI script runtime)
  • PowerShell (pwsh) for Windows installer runtime
  • Python 3 (validation runner and build checks)
  • Node.js + npx (skills CLI install/remove/list flows)
  • jq (required for harness artifact build rendering)
  • make (task entrypoints for build/check workflows)

Commands & Scripts

  • Build everything:
    • make build
  • Verify generated artifacts + guardrails drift:
    • make check
  • Build/check skills only:
    • make build-skills
    • make check-skills
  • Build/check harness artifacts only:
    • make build-harness
    • make check-harness
  • Run validation suite:
    • make validation
    • or python3 validation/run-validation-tests.py
  • Installers:
    • Bash: ./scripts/rubber-duck.sh install --opencode
    • PowerShell: ./scripts/rubber-duck.ps1 install -OpenCode

Read the full file on GitHub · 156 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. 5d ago First seen · 156 lines · 1,513 tokens per session scan A a5e36795042d

Subscribe to this mod's changes

rubber-duck AGENTS.md is an instructions file published in the GitHub repository sprngr/rubber-duck (8 stars, last pushed yesterday), licensed MIT. It adds 1,513 tokens to every session, about $0.0076 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.

agent-skillsai-agentsantivibeclaude-codedecision-qualitydeveloper-tools
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