mcp-harness-repo-maintainer

mcp-harness-repo-maintainer is a skill for Claude Code from Arenukvern/skill_steward. It costs 88 tokens per session (4,376 once invoked), scanned C, a copy of mcp-harness-repo-maintainer, MIT.

A maintenance guide for repositories that provide command-line tools and MCP adapters over shared core code. It defines how actions, tests, probes, and interfaces should fit together.

In plain words
What is it for?
Use it when adding or improving typed actions, probes, benchmarks, CLI and MCP parity, or core-library organization in a harness repository.
Why use it?
It helps prevent duplicated logic and mismatched behavior between command-line and agent-facing interfaces. It also provides checks for whether the repository works correctly from a clean start.

Skill for Claude Code

Written for Claude Code: paths in frontmatter. Also seen: mentions AGENTS.md.

Part of the skill-steward plugin — 15 skills shipped together

Good fit Use it when adding or improving typed actions, probes, benchmarks, CLI and MCP parity, or core-library organization in a harness repository.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/arenukvern/skill_steward/mcp-harness-repo-maintainer
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 Arenukvern/skill_steward --skill mcp-harness-repo-maintainer
Clone the repo
git clone --depth 1 https://github.com/Arenukvern/skill_steward

Made for: Claude Code.

Or install skill-steward, the plugin that ships this one along with the rest of its 15 skills.

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 mcp-harness-repo-maintainer

README.md
[![agentmods](https://agentmods.dev/badge/skills/arenukvern/skill_steward/mcp-harness-repo-maintainer/github.svg)](https://agentmods.dev/skills/arenukvern/skill_steward/mcp-harness-repo-maintainer)
Your own site
<a href="https://agentmods.dev/skills/arenukvern/skill_steward/mcp-harness-repo-maintainer"><img src="https://agentmods.dev/badge/skills/arenukvern/skill_steward/mcp-harness-repo-maintainer/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 mcp-harness-repo-maintainer

Your own site · 80×15
<a href="https://agentmods.dev/skills/arenukvern/skill_steward/mcp-harness-repo-maintainer"><img src="https://agentmods.dev/badge/skills/arenukvern/skill_steward/mcp-harness-repo-maintainer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 88 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,376 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod 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 $0.00088 $0.04376
Opus 5 $0.00044 $0.02188
Sonnet 5 $0.00018 $0.00875
Haiku 4.5 $0.00009 $0.00438

Measured 12d ago against content hash 84b07d7cfa58, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade C, and why

mcp-harness-repo-maintainer scanned grade C with 2 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 12d 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.

Downloads and executes remote codehighSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

1. Released adopter or CI path: `curl -fsSL https://raw.githubusercontent.com/Arenukvern/skill_steward/main/install.sh | bash`, then `steward <command>`.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

1. Released adopter or CI path: `curl -fsSL https://raw.githubusercontent.com/Arenukvern/skill_steward/main/install.sh | bash`, then `steward <command>`.
Origin

This is a copy

100% identical to mcp-harness-repo-maintainer — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/mcp-harness-repo-maintainer/SKILL.md · 280 lines

How it starts

The opening of the file, as written. The whole thing — 280 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Action Contract & Harness Repo Maintainer

Build and maintain repo-local action contracts and harnesses where agents execute and humans steer. The historical mcp- name remains because many adopters arrive through MCP work, but this skill is not MCP-only. For general app, library, tool, plugin, or meta-repo stewardship baselines, use repo-quality-system-lifecycle first; use this skill only when typed actions, probes, benchmarks, or CLI/MCP parity are in scope.

Core principle (action-contract and harness repos)

MCP and CLI are thin interfaces—APIs for agents and CI. Core contains the real logic, schemas, and registries. Adapters parse wire format (argv, MCP JSON-RPC); they delegate immediately.

Agents / CI  →  CLI ──┐
                      ├──► Core (logic, contracts, tests)
Agents / chat →  MCP ──┘

Full layering: core-and-interfaces.md. Parity: every MCP tool must call the same core entrypoint as its CLI twin.

Progressive Automation (Agent-Driven Workflows): Harnesses should let agents turn repeated friction into reviewed, durable capability. If an agent discovers a complex fix or command sequence, it should capture an unknown case or typed action candidate with owner, risk class, inputs, outputs, effects, provenance, and verification. Permanent steward.yaml changes must go through reviewable diffs and validation; do not teach agents to save raw bash permanently from MCP.

Goal-first adoption: The original user goal remains the acceptance check. Tool repair, install work, wrappers, action candidates, evals, and refactors are detours unless they directly solve that goal or preserve a reusable lesson. After two failed repair/setup attempts, stop tool restoration, use a type-native command or portable fallback when possible, record the friction, return to the task, and do not promote from that same detour.

Product experiment ownership: When the goal is visual quality, shader behavior, loader correctness, renderer throughput, or performance, the product repo owns the high-throughput experiment runner and oracle. Steward can validate or summarize an experiment-campaign-summary/v1 artifact after the product loop has produced captures/metrics. Do not promote a Steward action, benchmark, or MCP tool as product acceleration unless the product campaign names what surface changed or was directly proven.

Read the full file on GitHub · 280 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. 12d ago First seen · 280 lines · 88 tokens per session scan C 84b07d7cfa58

Subscribe to this mod's changes

mcp-harness-repo-maintainer is a skill published in the GitHub repository Arenukvern/skill_steward (11 stars, last pushed 28d ago), licensed MIT. It adds 88 tokens to every session and 4,376 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). It is 100% identical to mcp-harness-repo-maintainer, differing in 0 lines, and is treated as a copy.