yuin/goldmark is a Markdown parser written in Go that converts Markdown into structured output such as HTML while supporting CommonMark and custom syntax extensions. Developers use it to process, analyze, and generate Markdown in Go applications and tools. The catalogue add-ons provide agent instructions and integrations for working with the parser.
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.
npx skills add yuin/goldmark --skill migrate-goldmark-extension-v1-to-v2git clone --depth 1 https://github.com/yuin/goldmarkWrote 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.
[](https://agentmods.dev/skills/yuin/goldmark/migrate-goldmark-extension-v1-to-v2)<a href="https://agentmods.dev/skills/yuin/goldmark/migrate-goldmark-extension-v1-to-v2"><img src="https://agentmods.dev/badge/skills/yuin/goldmark/migrate-goldmark-extension-v1-to-v2/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.
<a href="https://agentmods.dev/skills/yuin/goldmark/migrate-goldmark-extension-v1-to-v2"><img src="https://agentmods.dev/badge/skills/yuin/goldmark/migrate-goldmark-extension-v1-to-v2.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00026 | $0.01944 |
| Opus 5 | $0.00013 | $0.00972 |
| Sonnet 5 | $0.00005 | $0.00389 |
| Haiku 4.5 | $0.00003 | $0.00194 |
Grade A, and why
migrate-goldmark-extension-v1-to-v2 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 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.
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.
How it starts
The opening of the file, as written. The whole thing — 163 lines — stays where its author put it; the contents beside it link to each section on GitHub.
migrate-goldmark-extension-v1-to-v2
Description
This skill helps you migrate a goldmark (https://github.com/yuin/goldmark) extension from version 1 to version 2. It provides guidance on the changes needed to update your project to be compatible with the new version of goldmark.
Knowledges
- CommonMark key points : List of key points of CommonMark spec that you should be aware of when implementing a goldmark extension.
- Breaking changes in v2 : List of breaking changes in goldmark v2 that you should be aware of when migrating your extension from v1 to v2.
- How to create an extension : Guide on how to create a goldmark extension in v2, including the new extension pattern and how to implement parser and renderer extensions.
Migration steps
Overview of the migration process
- Create a migration plan for the extension.
- MUST ask human to confirm that the migration plan is acceptable before proceeding with the migration.
- MUST ask human to how to test the extension after migration before proceeding with the migration.
- e.g. : "How do you want to test the extension after migration? Do you have any test cases or examples that you want to use for testing?"
- Execute the migration plan to update the extension code to be compatible with goldmark v2.
- Update the test cases to ensure that the extension works as expected with goldmark v2.
- Test the extension with goldmark v2 to ensure that it works as expected. If there are any issues, fix them and re-test until the extension works as expected.
- Update the documentation to reflect any changes made during the migration process.
Create a migration plan
Task
- Make sure you have read and understood the Breaking changes in v2 document.
- Make sure you have read and understood the How to create an extension document.
- You create a ./features/goldmark-migration-plan.md file that contains a migration plan for the extension.
What ships with it
1 file 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.
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.
- 12d ago First seen · 163 lines · 26 tokens per session scan A 6bf8541cea7a
migrate-goldmark-extension-v1-to-v2 is a skill published in the GitHub repository yuin/goldmark (5,011 stars, last pushed yesterday), licensed MIT. It adds 26 tokens to every session and 1,944 once invoked, about $0.0001 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 2026-08-30.
Other skills, from other repositories
use-modern-go
Use the Modern Go Guidelines CLI whenever writing, modifying, fixing, or refactoring Go code. Apply its version-specific guidance to generated changes.
jwx-guide-v4
Guide for developing Go applications with github.com/lestrrat-go/jwx v4 — parse/sign JWTs, work with JWS/JWE/JWK, pick algorithms, and avoid the common footguns. For developers using jwx, not for developing the library itself.
gograph
Go repository intelligence for Claude Code. Use when reading, navigating, editing, reviewing, or refactoring a Go codebase. Exposes 64 query, analysis, and workflow capabilities through the local gograph MCP server, including bounded first-call exploration, AST-aware call graphs, blast-radius analysis, impact, and…
go-127
What changed in Go 1.27 (released August 2026) and how it changes the way Go is written in pi-go. Use this skill when writing or reviewing Go that could use a 1.27 feature, when bumping the go directive in go.mod, when a build or test behaves differently after a toolchain upgrade, or when code-guidelines-go points…
bubbletea-testing
Use this skill whenever writing tests for Bubble Tea (charmbracelet/bubbletea) TUI applications in Go. Triggers include any mention of testing Bubble Tea models, teatest, golden file testing for TUIs, testing tea.Cmd or tea.Msg, snapshot testing terminal output, or writing tests for any Go CLI/TUI that uses the Elm…
design-review
Deep design review of Go codebase — naming, structure, consistency, interfaces, error handling. Scores each dimension and provides actionable fixes.