upstream

upstream is a skill for Claude Code, Codex from NexaDuo/mARC. It costs 83 tokens per session (1,298 once invoked), scanned A, original, MIT.

An opt-in workflow for collecting useful lessons from a project and proposing them to the upstream product repository. It reads local agent rules and commit history, removes private details, and drafts a GitHub Pull Request or Issue for human review.

In plain words
What is it for?
Use it to turn field-discovered process changes, bug fixes, and rule improvements into sanitized upstream contributions.
Why use it?
It helps teams share improvements without accidentally exposing company names, internal systems, credentials, or client information. Nothing is sent upstream without explicit approval.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions AGENTS.md.

Good fit Use it to turn field-discovered process changes, bug fixes, and rule improvements into sanitized upstream contributions.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/nexaduo/marc/upstream
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.

Any agent
npx skills add NexaDuo/mARC --skill upstream
Clone the repo
git clone --depth 1 https://github.com/NexaDuo/mARC

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 upstream

README.md
[![agentmods](https://agentmods.dev/badge/skills/nexaduo/marc/upstream/github.svg)](https://agentmods.dev/skills/nexaduo/marc/upstream)
Your own site
<a href="https://agentmods.dev/skills/nexaduo/marc/upstream"><img src="https://agentmods.dev/badge/skills/nexaduo/marc/upstream/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for upstream

Your own site · 80×15
<a href="https://agentmods.dev/skills/nexaduo/marc/upstream"><img src="https://agentmods.dev/badge/skills/nexaduo/marc/upstream.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 83 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,298 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00083 $0.01298
Opus 5 $0.00042 $0.00649
Sonnet 5 $0.00017 $0.00260
Haiku 4.5 $0.00008 $0.00130

Measured yesterday against content hash 2caabf3f88c7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

upstream 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.

core/skills/upstream/SKILL.md · 131 lines

How it starts

The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/marc:upstream — upstream process improvements & field lessons

You are running the mARC upstream contribution workflow (persona: @scribe). Your job is to help the team in a consuming repository capture high-value operational lessons, rule refinements, or bugfixes discovered in the field and contribute them back to the upstream mARC product repo — safely, sanitarily, and with explicit human opt-in.


Operating Invariant: Context Gating & Zero Leakage

  • Self-improvement is context-gated — no autonomous upstream writes. When mARC runs installed in a user's repository, product-level improvements must NEVER be pushed autonomously. All upstream contributions are opt-in, human-approved, and strictly sanitized before submission. (origin: #46 · 2026-07-06)
  • Hard Anti-Anchoring & Genericization Gate. Every candidate rule or improvement destined for upstream must be 100% stack-agnostic. Remove all references to the consuming repository's stack, company name, private service names, internal URLs, credentials, and internal issue numbers. (origin: #66 · 2026-07-09)
  • Nothing is transmitted or written silently. You MUST present the exact sanitized diff and commit message to the user and obtain an explicit confirmation before creating any branch, issue, or pull request on the upstream repository. (origin: #46 · 2026-07-06)

Operating Loop

Step 1 — Harvest Candidate Lessons

Scan the current workspace for process adaptations and emergent operational rules:

  1. Local Governance & Config: Read ${{{ project_dir_env }}:-$PWD}/AGENTS.md and ${{{ project_dir_env }}:-$PWD}/{{ agents_dir }}/team.toml.
  2. Session Transcripts & Notes: Check local session memory indices or recent .md notes for recurring friction points or debugging workarounds.
  3. Recent Commits: Inspect recent commit messages and diffs for changes touching agent instructions, hooks, CI gates, or operational scripts.

Read the full file on GitHub · 131 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 First seen · 131 lines · 83 tokens per session scan A 2caabf3f88c7

Subscribe to this mod's changes

upstream is a skill published in the GitHub repository NexaDuo/mARC (6 stars, last pushed yesterday), licensed MIT. It adds 83 tokens to every session and 1,298 once invoked, about $0.0004 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 2026-09-09.