Gum skills-writer

Creates and updates skill files (.claude/skills/*/SKILL.md) by reading source code and condensing knowledge into concise reference guides. Use when asked to create a new skill, update an existing skill, or document a subsystem for Claude Code agent context.

install

source · Clone the upstream repo

git clone https://github.com/vchelaru/Gum

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/vchelaru/Gum "$T" && mkdir -p ~/.claude/skills && cp -r "$T/.claude/skills/skills-writer" ~/.claude/skills/vchelaru-gum-skills-writer && rm -rf "$T"

manifest: .claude/skills/skills-writer/SKILL.md

Skills Writer

Process

Read all source files relevant to the skill topic.
Check
```
.claude/skills/
```
for existing skill files to match style and depth.
Distill non-obvious behaviors, relationships, and gotchas into SKILL.md. Obvious things (property names, method signatures) do not belong.

Skill File Rules

Length: Under 500 lines; aim for under 100 for focused topics.
Naming: Kebab-case noun phrases for the directory (e.g.,
```
gum-tool-undo
```
).
Frontmatter:
```
name
```
,
```
description
```
(third person, specific — state what the skill covers AND when to load it).
Structure:
```
##
```
sections. Tables for key-file maps and event/class lists. Prose for relationships and non-obvious behavior.
Progressive disclosure: High-level architecture at the top. Link to separate detail files for advanced content (e.g.,
```
[xnafiddle.md](xnafiddle.md)
```
) rather than inlining everything.

What to Include

Architecture: how major pieces fit together and why.
Non-obvious gotchas: surprising behavior, ordering dependencies, naming mismatches.
Key file map: table of file to purpose (one-liners only).
Specific identifiers only when behavior is surprising or the name is misleading.

What to Exclude

Full class outlines or property lists — readable directly from source.
Code examples unless a snippet captures an irreplaceable non-obvious pattern.
Time-sensitive info (versions, dates, migration notes).
Anything Claude already knows from general C# or .NET knowledge.

Output

Write the skill file to

.claude/skills/<skill-name>/SKILL.md

. Create the directory if needed. Only create additional files if the content is large enough to warrant referenced detail files.