MCPGateway: Skill for Codex

.codex/skills/mcaf-devex/SKILL.md

mcaf-devex is a skill for Codex from managedcode/MCPGateway. It costs 49 tokens per session (793 once invoked), scanned A, a copy of dotnet-mcaf-devex, MIT.

A developer-experience guide for software projects with several components. It focuses on setup, running, debugging, testing, and the everyday edit-and-check cycle developers use while changing code.

In plain words
What is it for?
Use it to document or improve first-time setup, build and run commands, debugging, tests, cross-platform tasks, and the local development loop.
Why use it?
It helps remove fragile setup steps, inconsistent local environments, and unclear commands that slow onboarding or debugging. The result is a more repeatable way to work on the repository.

Skill for Codex

Written for Codex: installed under .codex/. Also seen: mentions AGENTS.md.

This is managedcode/MCPGateway's own configuration. It tells Codex how to work on MCPGateway 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 MCPGateway configures →

Reuse

Borrowing it

Nothing to install: this file belongs to managedcode/MCPGateway. 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/managedcode/MCPGateway/main/.codex/skills/mcaf-devex/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/managedcode/MCPGateway

Made for: 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 mcaf-devex

README.md
[![agentmods](https://agentmods.dev/badge/skills/managedcode/mcpgateway/mcaf-devex/github.svg)](https://agentmods.dev/skills/managedcode/mcpgateway/mcaf-devex)
Your own site
<a href="https://agentmods.dev/skills/managedcode/mcpgateway/mcaf-devex"><img src="https://agentmods.dev/badge/skills/managedcode/mcpgateway/mcaf-devex/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 mcaf-devex

Your own site · 80×15
<a href="https://agentmods.dev/skills/managedcode/mcpgateway/mcaf-devex"><img src="https://agentmods.dev/badge/skills/managedcode/mcpgateway/mcaf-devex.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 793 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 89% 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 $0.00049 $0.00793
Opus 5.5 $0.00020 $0.00317
Sonnet 5.5 $0.00010 $0.00159
Haiku 4.5 $0.00005 $0.00079

Measured 1mo ago against content hash a495662cf6e2, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mcaf-devex 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 1mo 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.

Origin

This is a copy

89% identical to dotnet-mcaf-devex — 25 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.

.codex/skills/mcaf-devex/SKILL.md · 99 lines

How it starts

The opening of the file, as written. The whole thing — 99 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MCAF: Developer Experience

Trigger On

  • the repo is hard to run, test, debug, or onboard into
  • local setup differs too much across contributors
  • the inner loop is slow or undocumented

Value

  • produce a concrete project delta: code, docs, config, tests, CI, or review artifact
  • reduce ambiguity through explicit planning, verification, and final validation skills
  • leave reusable project context so future tasks are faster and safer

Do Not Use For

  • production deployment or pipeline policy
  • pure documentation cleanup with no developer workflow impact

Inputs

  • the current local setup and first-run path
  • actual build, run, debug, and test commands
  • pain points in onboarding or the inner loop

Quick Start

  1. Read the nearest AGENTS.md and confirm scope and constraints.
  2. Run this skill's Workflow through the Ralph Loop until outcomes are acceptable.
  3. Return the Required Result Format with concrete artifacts and verification evidence.

Workflow

  1. Find the slowest or most fragile part of the inner loop:
    • clone and setup
    • build
    • run and debug
    • test
  2. Standardize tasks before optimizing them.
  3. Prefer one documented way to run the full solution locally.
  4. Pull only the references that match the local-dev problem you are fixing.

Deliver

  • lower-friction local workflow
  • better onboarding
  • reproducible build, run, test, and debug paths

Validate

  • a newcomer can follow the docs without hidden setup knowledge
  • the inner loop is explicit and reproducible
  • cross-platform or containerized guidance is used only where it helps
  • local development uses real services, containers, or sandbox environments instead of fakes or stubs

Ralph Loop

Use the Ralph Loop for every task, including docs, architecture, testing, and tooling work.

  1. Plan first (mandatory):
    • analyze current state
    • define target outcome, constraints, and risks
    • write a detailed execution plan
    • list final validation skills to run at the end, with order and reason
  2. Execute one planned step and produce a concrete delta.
  3. Review the result and capture findings with actionable next fixes.
  4. Apply fixes in small batches and rerun the relevant checks or review steps.
  5. Update the plan after each iteration.
  6. Repeat until outcomes are acceptable or only explicit exceptions remain.
  7. If a dependency is missing, bootstrap it or return status: not_applicable with explicit reason and fallback path.

Read the full file on GitHub · 99 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 1mo ago First seen · 99 lines · 49 tokens per session scan A a495662cf6e2

Subscribe to this mod's changes

mcaf-devex is a skill published in the GitHub repository managedcode/MCPGateway (5 stars, last pushed 8d ago), licensed MIT. It adds 49 tokens to every session and 793 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 89% identical to dotnet-mcaf-devex, differing in 25 lines, and is treated as a copy.

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