mtga: Skill for Codex

.codex/skills/ast-grep/SKILL.md

ast-grep is a skill for Codex from BiFangKNT/mtga. It costs 62 tokens per session (847 once invoked), scanned A, original, AGPL-3.0.

A tool for searching and rewriting code by its structure rather than by matching text. It uses the code's syntax tree, so it can distinguish how a piece of code is written and where it appears.

In plain words
What is it for?
Use it to find syntax shapes, require one pattern to contain another, combine matching conditions, or apply consistent code changes across a repository.
Why use it?
Plain-text search can match comments, strings, or unrelated formatting, while structure-aware rules target the actual code pattern. This makes broad refactors more precise.

Skill for Codex

Written for Codex: installed under .codex/.

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

About the project

MTGA is a local proxy application that lets users work around an IDE's fixed model-provider restrictions by forwarding requests to configured AI services. It supports Windows and macOS and connects the Trae IDE with providers including OpenAI-compatible, Anthropic, and Gemini services.

BiFangKNT/mtga · 1,179 stars · on GitHub

Reuse

Borrowing it

Nothing to install: this file belongs to BiFangKNT/mtga. 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/BiFangKNT/mtga/tauri/.codex/skills/ast-grep/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/BiFangKNT/mtga

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 ast-grep

README.md
[![agentmods](https://agentmods.dev/badge/skills/bifangknt/mtga/ast-grep.svg)](https://agentmods.dev/skills/bifangknt/mtga/ast-grep)
Your own site
<a href="https://agentmods.dev/skills/bifangknt/mtga/ast-grep"><img src="https://agentmods.dev/badge/skills/bifangknt/mtga/ast-grep.svg" alt="Measured on agentmods" height="20"></a>
Per session 62 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 847 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 unknown 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 $0.00062 $0.00847
Opus 5 $0.00031 $0.00424
Sonnet 5 $0.00012 $0.00169
Haiku 4.5 $0.00006 $0.00085

Measured yesterday against content hash aa3fcd7c3d8e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

ast-grep 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.

.codex/skills/ast-grep/SKILL.md · 139 lines

The source is not reproduced here

Licensed AGPL-3.0

The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

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. yesterday First seen · 139 lines · 62 tokens per session scan A aa3fcd7c3d8e

Subscribe to this mod's changes

ast-grep is a skill published in the GitHub repository BiFangKNT/mtga (1,179 stars, last pushed 2mo ago), licensed AGPL-3.0. It adds 62 tokens to every session and 847 once invoked, about $0.0003 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 2026-09-04.

Related

Other skills, from other repositories

debug-optimize-lcp

Guides debugging and optimizing Largest Contentful Paint (LCP) using Chrome DevTools MCP tools. Use this skill whenever the user asks about LCP performance, slow page loads, Core Web Vitals optimization, or wants to understand why their page's main content takes too long to appear. Also use when the user mentions…

ChromeDevTools/chrome-devtools-mcp · 99 tokens

systematic-debugging

Use when debugging a failing test, build error, or runtime issue that isn't immediately obvious. Guides a 4-phase root cause analysis instead of random fix attempts.

open-metadata/OpenMetadata · 37 tokens

diagnose

Trace from a reproduced symptom to the source code that causes it. Pin the specific file and approximate line, rate confidence in the cause and clarity of the fix independently, and always propose a concrete fix.

emdash-cms/emdash · 43 tokens

repro-admin

Reproduce an EmDash admin UI bug. Attach a container, start the demo dev server, drive the admin with agent-browser using the dev-bypass session, and capture the reproduction as screenshots plus a replayable transcript.

emdash-cms/emdash · 48 tokens

log-error-digest

Analyze log files to troubleshoot errors, identify peak error periods, and produce error clustering, frequency statistics, and time distribution reports. Supports JSON, syslog, and Nginx formats with automatic detection. Use when a user uploads a .log file and asks to analyze errors, find patterns, debug issues, or…

zebbern/claude-code-guide · 71 tokens

byted-util-volcengine-detect-retry

An orchestration workflow for Volcengine Cloud Detect, a service that checks websites or network endpoints from test locations.

bytedance/agentkit-samples · 101 tokens