mtg-mcp-server: Skill for Claude Code

.agents/skills/superpowers/subagent-driven-development/SKILL.md

subagent-driven-development is a skill for Claude Code, Codex from j4th/mtg-mcp-server. It costs 17 tokens per session (7,533 once invoked), scanned C, a copy of subagent-driven-development, MIT.

A development workflow that assigns each independent implementation task to a fresh coding agent, reviews that task, and then reviews the completed branch. A branch is a separate line of Git work used to contain changes.

In plain words
What is it for?
Use it to carry out implementation plans made up of independent tasks while reviewing each result and the final branch.
Why use it?
It gives each task a focused context and adds checks for both requirement compliance and code quality.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions subagents; installed under .agents/ (shared by several agents).

This is j4th/mtg-mcp-server's own configuration. It tells Claude Code and Codex how to work on mtg-mcp-server 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 mtg-mcp-server configures →

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is "Dispatch final code reviewer (../requesting-code-review/code-reviewer.md)" [shape=box];.

Reuse

Borrowing it

Nothing to install: this file belongs to j4th/mtg-mcp-server. 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/j4th/mtg-mcp-server/main/.agents/skills/superpowers/subagent-driven-development/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/j4th/mtg-mcp-server

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 subagent-driven-development

README.md
[![agentmods](https://agentmods.dev/badge/skills/j4th/mtg-mcp-server/subagent-driven-development/github.svg)](https://agentmods.dev/skills/j4th/mtg-mcp-server/subagent-driven-development)
Your own site
<a href="https://agentmods.dev/skills/j4th/mtg-mcp-server/subagent-driven-development"><img src="https://agentmods.dev/badge/skills/j4th/mtg-mcp-server/subagent-driven-development/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 subagent-driven-development

Your own site · 80×15
<a href="https://agentmods.dev/skills/j4th/mtg-mcp-server/subagent-driven-development"><img src="https://agentmods.dev/badge/skills/j4th/mtg-mcp-server/subagent-driven-development.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 17 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 7,533 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin 92% 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 $0.00017 $0.07533
Opus 5.5 $0.00007 $0.03013
Sonnet 5.5 $0.00003 $0.01507
Haiku 4.5 $0.00002 $0.00753

Measured 3d ago against content hash 8dde5589ee08, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade C, and why

subagent-driven-development scanned grade C with 1 finding 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 3d 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.

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

delete this plan's workspace (`rm -rf <workspace>`) — the git history is
Origin

This is a copy

92% identical to subagent-driven-development — 288 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.

.agents/skills/superpowers/subagent-driven-development/SKILL.md · 569 lines

How it starts

The opening of the file, as written. The whole thing — 569 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Subagent-Driven Development

Execute plan by dispatching a fresh implementer subagent per task, a task review (spec compliance + code quality) after each, and a broad whole-branch review at the end.

Why subagents: You delegate tasks to specialized agents with isolated context. By precisely crafting their instructions and context, you ensure they stay focused and succeed at their task. They should never inherit your session's context or history — you construct exactly what they need. This also preserves your own context for coordination work.

Core principle: Fresh subagent per task + task review (spec + quality) + broad final review = high quality, fast iteration

Narration: between tool calls, narrate at most one short line — the ledger and the tool results carry the record.

Continuous execution: Do not pause to check in with your human partner between tasks. Execute all tasks from the plan without stopping. The only reasons to stop are the four named below, or all tasks complete. "Should I continue?" prompts and progress summaries waste their time — they asked you to execute the plan, so execute it.

Rulings, not stalls. A running plan does not wait on a human. Conflicts, ambiguities, plan defects, a cap you would have asked to exceed — decide them. The spec is the binding authority, the plan is its argument, and your judgment settles what neither answers. Record every decision in the ledger as Ruling: <what you decided> — <why> — <what it costs if wrong>, and keep going. A wrong ruling costs rework your human partner can see and undo; a session parked on a question costs their whole day and buys nothing.

Four things stop you, and only these: an irreversible or destructive operation; a security-sensitive action; a side effect outside this worktree that norms say you ask about first (a merge, a push to a shared branch, a publish); and a plan so broken that every path forward is a guess. For those, stop and ask.

When to Use

digraph when_to_use {
    "Have implementation plan?" [shape=diamond];
    "Tasks mostly independent?" [shape=diamond];
    "Partner chose inline, or no subagent tool?" [shape=diamond];
    "subagent-driven-development" [shape=box];
    "executing-plans" [shape=box];
    "Manual execution or brainstorm first" [shape=box];

    "Have implementation plan?" -> "Tasks mostly independent?" [label="yes"];
    "Have implementation plan?" -> "Manual execution or brainstorm first" [label="no"];
    "Tasks mostly independent?" -> "Partner chose inline, or no subagent tool?" [label="yes"];
    "Tasks mostly independent?" -> "Manual execution or brainstorm first" [label="no - tightly coupled"];
    "Partner chose inline, or no subagent tool?" -> "executing-plans" [label="yes"];
    "Partner chose inline, or no subagent tool?" -> "subagent-driven-development" [label="no"];
}

Read the full file on GitHub · 569 lines

Files

What ships with it

6 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. 3d ago First seen · 569 lines · 17 tokens per session scan C 8dde5589ee08

Subscribe to this mod's changes

subagent-driven-development is a skill published in the GitHub repository j4th/mtg-mcp-server (20 stars, last pushed 2d ago), licensed MIT. It adds 17 tokens to every session and 7,533 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it C with 1 finding (recursive force delete). It is 92% identical to subagent-driven-development, differing in 288 lines, and is treated as a copy.

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