mtg-mcp-server: Skill for Claude Code

.agents/skills/superpowers/writing-plans/SKILL.md

writing-plans is a skill for Claude Code, Codex from j4th/mtg-mcp-server. It costs 21 tokens per session (2,313 once invoked), scanned A, original, MIT.

A guide for writing detailed implementation plans before changing code. It explains how to break requirements into small tasks, name the files and tests involved, and save the plan in a standard location.

In plain words
What is it for?
Use it to plan multi-step coding work, identify affected files, define tests, and record risks before implementation.
Why use it?
It turns a broad specification into concrete steps that another engineer can follow without already knowing the codebase.

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 →

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/writing-plans/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 writing-plans

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/j4th/mtg-mcp-server/writing-plans"><img src="https://agentmods.dev/badge/skills/j4th/mtg-mcp-server/writing-plans.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,313 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 $0.00021 $0.02313
Opus 5.5 $0.00008 $0.00925
Sonnet 5.5 $0.00004 $0.00463
Haiku 4.5 $0.00002 $0.00231

Measured 3d ago against content hash a6c67c190006, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

writing-plans 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 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.

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

Copies of this mod

1 near-identical copy found in the catalogue:

.agents/skills/superpowers/writing-plans/SKILL.md · 205 lines

How it starts

The opening of the file, as written. The whole thing — 205 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Writing Plans

Overview

Write implementation plans for an engineer who has not seen this codebase or this spec. Assume they write idiomatic code in the project's language once they know the exact interface and the exact test, and that they will make a reasonable choice wherever the plan leaves one open. What they cannot know is what you decided: which files, which names and signatures, which values from the spec, which tests prove each task. Document those. Give them the whole plan as bite-sized tasks. DRY. YAGNI. TDD. Frequent commits.

Announce at start: "I'm using the writing-plans skill to create the implementation plan."

Context: If working in an isolated worktree, it should have been created via the superpowers:using-git-worktrees skill at execution time.

Save plans to: docs/superpowers/plans/YYYY-MM-DD-<feature-name>.md

  • (User preferences for plan location override this default)

Scope Check

If the spec covers multiple independent subsystems, it should have been broken into sub-project specs during brainstorming. If it wasn't, suggest breaking this into separate plans — one per subsystem. Each plan should produce working, testable software on its own.

File Structure

Before defining tasks, map out which files will be created or modified and what each one is responsible for. This is where decomposition decisions get locked in.

  • Design units with clear boundaries and well-defined interfaces. Each file should have one clear responsibility.
  • You reason best about code you can hold in context at once, and your edits are more reliable when files are focused. Prefer smaller, focused files over large ones that do too much.
  • Files that change together should live together. Split by responsibility, not by technical layer.
  • In existing codebases, follow established patterns. If the codebase uses large files, don't unilaterally restructure - but if a file you're modifying has grown unwieldy, including a split in the plan is reasonable.

Read the full file on GitHub · 205 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. 3d ago First seen · 205 lines · 21 tokens per session scan A a6c67c190006

Subscribe to this mod's changes

writing-plans is a skill published in the GitHub repository j4th/mtg-mcp-server (20 stars, last pushed 2d ago), licensed MIT. It adds 21 tokens to every session and 2,313 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-10-21.

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