Agent skill

Skill Porter

by jduncan-rva in jduncan-rva/skill-porter

Converts Claude Code skills to Gemini CLI extensions and vice versa.

Install Skill Porter

skills CLI

$ npx skills add jduncan-rva/skill-porter --skill skill-porter -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install jduncan-rva/skill-porter skill-porter --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "skill-porter" agent skill from https://github.com/jduncan-rva/skill-porter/tree/main into .claude/skills/skill-porter/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "skill-porter", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add jduncan-rva/skill-porter --skill skill-porter -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install jduncan-rva/skill-porter skill-porter --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "skill-porter" agent skill from https://github.com/jduncan-rva/skill-porter/tree/main into .agents/skills/skill-porter/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "skill-porter", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add jduncan-rva/skill-porter --skill skill-porter -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install jduncan-rva/skill-porter skill-porter --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "skill-porter" agent skill from https://github.com/jduncan-rva/skill-porter/tree/main into .cursor/skills/skill-porter/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "skill-porter", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add jduncan-rva/skill-porter --skill skill-porter -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install jduncan-rva/skill-porter skill-porter --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "skill-porter" agent skill from https://github.com/jduncan-rva/skill-porter/tree/main into .gemini/skills/skill-porter/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "skill-porter", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install jduncan-rva/skill-porter skill-porter

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add jduncan-rva/skill-porter --skill skill-porter -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "skill-porter" agent skill from https://github.com/jduncan-rva/skill-porter/tree/main into .github/skills/skill-porter/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "skill-porter", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add jduncan-rva/skill-porter --skill skill-porter -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install jduncan-rva/skill-porter skill-porter --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "skill-porter" agent skill from https://github.com/jduncan-rva/skill-porter/tree/main into .opencode/skills/skill-porter/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "skill-porter", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: skill-porter
GitHub stars: 191
Token cost: ~2k tokens
SKILL.md length: 736 words
Files: 50
Skills in repo: 1
Repo updated: Dec 2, 2025
First seen: Oct 7, 2026
Licence: MIT

At a glance

Converts Claude Code skills to Gemini CLI extensions and vice versa.

Works in 7 steps: Analyze the source directory structure → Detect which platform it's built for → Extract metadata, MCP configuration, and… → …
The user wants to make a skill cross-platform compatible
SKILL.md covers Core Capabilities, Conversion Process, Platform Differences Handled and Usage Examples, plus 5 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Skill Porter is an agent skill from jduncan-rva/skill-porter. Converts Claude Code skills to Gemini CLI extensions and vice versa. Use when the user wants to make a skill cross-platform compatible, port a skill between platforms, or create a universal extension that works on both Claude Code and Gemini CLI.

Its SKILL.md is about 2k tokens, which your agent loads only when the skill is triggered. The skill folder holds 55 other files (for example `.claude-plugin/marketplace.json`, `CONTRIBUTING.md` and `GEMINI.md`).

It sits in Agent Workflows. It works with Model Context Protocol. The repository describes itself as: Universal tool to convert Claude Code skills to Gemini CLI extensions and vice versa. The licence is MIT.

When your agent uses it

The user wants to make a skill cross-platform compatible
Port a skill between platforms
Create a universal extension that works on both Claude Code and Gemini CLI

Example prompts

“Use the skill-porter skill to convert Claude Code skills to Gemini CLI extensions and vice versa”
“/skill-porter”

Requirements

Pre-approved tools (allowed-tools): Read, Write, Edit, Glob, Grep, Bash

Workflow steps

7 steps, taken from the first numbered list in SKILL.md.

Analyze the source directory structure
Detect which platform it's built for
Extract metadata, MCP configuration, and documentation
Transform the data to target platform format
Generate required files for target platform
Validate output meets all requirements
Report what was converted and any manual steps needed

What it can do on your machine

Read from SKILL.md and the folder at commit 7ad93ec. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves these tools, so the agent can use them without asking each time:
- Read
- Write
- Edit
- Glob
- Grep
- Bash
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are javascript).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Skill Porter loads about 2k tokens when it runs. Until then it costs about 65 tokens; SKILL.md has 736 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~65
When it runs · the whole SKILL.md, loaded when a task matches: ~2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check: notes

The automated check noted patterns worth knowing about, such as sudo or a known installer.

NotePre-approves every shell command (allowed-tools: Bash)SKILL.md
```
allowed-tools: Read, Write, Edit, Glob, Grep, Bash
```

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from jduncan-rva/skill-porter at commit 7ad93ec, republished under its MIT licence (© jduncan-rva). 736 words, ~2,029 tokens.

Download SKILL.mdSave it as .claude/skills/skill-porter/SKILL.md (or your agent's skills folder). This skill also uses 49 other files; get the full folder from GitHub.

name: skill-porter
description: Converts Claude Code skills to Gemini CLI extensions and vice versa. Use when the user wants to make a skill cross-platform compatible, port a skill between platforms, or create a universal extension that works on both Claude Code and Gemini CLI.
allowed-tools: Read, Write, Edit, Glob, Grep, Bash

Skill Porter - Cross-Platform Skill Converter

This skill automates the conversion between Claude Code skills and Gemini CLI extensions, enabling true cross-platform AI tool development.

Core Capabilities

Bidirectional Conversion

Convert skills and extensions between platforms while preserving functionality:

Example requests:

"Convert this Claude skill to work with Gemini CLI"
"Make my Gemini extension compatible with Claude Code"
"Create a universal version of this skill that works on both platforms"
"Port the database-helper skill to Gemini"

Smart Platform Detection

Automatically analyzes directory structure to determine source platform:

Detection criteria:

Claude: Presence of SKILL.md with YAML frontmatter or .claude-plugin/marketplace.json
Gemini: Presence of gemini-extension.json or GEMINI.md context file
Universal: Has both platform configurations

Example requests:

"What platform is this skill built for?"
"Analyze this extension and tell me what needs to be converted"
"Is this a Claude skill or Gemini extension?"

Metadata Transformation

Intelligently converts between platform-specific formats:

Conversions handled:

YAML frontmatter ↔ JSON manifest
allowed-tools (whitelist) ↔ excludeTools (blacklist)
Environment variables ↔ settings schema
MCP server configuration paths
Platform-specific documentation formats

Example requests:

"Convert the metadata from this Claude skill to Gemini format"
"Transform the allowed-tools list to Gemini's exclude pattern"
"Generate a settings schema from these environment variables"

MCP Server Preservation

Maintains Model Context Protocol server configurations across platforms:

Example requests:

"Ensure the MCP server config works on both platforms"
"Update the MCP server paths for Gemini's ${extensionPath} variable"
"Validate that the MCP configuration is compatible"

Validation & Quality Checks

Ensures converted output meets platform requirements:

Validation checks:

Required files present (SKILL.md, gemini-extension.json, etc.)
Valid YAML/JSON syntax
Correct frontmatter structure
MCP server paths resolve correctly
Tool restrictions are valid
Settings schema is complete

Example requests:

"Validate this converted skill"
"Check if this Gemini extension meets all requirements"
"Is this conversion ready to install?"

Conversion Process

When you request a conversion, I will:

Analyze the source directory structure
Detect which platform it's built for
Extract metadata, MCP configuration, and documentation
Transform the data to target platform format
Generate required files for target platform
Validate output meets all requirements
Report what was converted and any manual steps needed

Platform Differences Handled

File Structure

Claude: SKILL.md + .claude-plugin/marketplace.json
Gemini: GEMINI.md + gemini-extension.json
Universal: Both sets of files + shared documentation

Metadata Format

Claude: YAML frontmatter in SKILL.md
Gemini: JSON manifest file
Conversion: Bidirectional YAML ↔ JSON transformation

Tool Restrictions

Claude: allowed-tools (whitelist - only listed tools permitted)
Gemini: excludeTools (blacklist - listed patterns blocked)
Conversion: Logic inversion with intelligent mapping

Configuration

Claude: Environment variables (user sets before running)
Gemini: Settings schema (prompted during installation)
Conversion: Infer schema from env vars or generate env var docs

MCP Server Paths

Claude: Relative paths from skill directory
Gemini: Uses ${extensionPath} variable substitution
Conversion: Automatic path transformation

Show full SKILL.md (291 more words)Show less

Usage Examples

Convert Claude Skill to Gemini

User: "I have a Claude skill at ./database-helper. Convert it to Gemini."
Claude: I'll analyze the skill and convert it to Gemini format...
- Detected Claude skill (found SKILL.md with frontmatter)
- Extracted metadata and MCP configuration
- Generated gemini-extension.json and GEMINI.md
- Transformed allowed-tools to excludeTools
- Created settings schema from environment variables
✓ Conversion complete! Ready to install with: gemini extensions install ./database-helper

Convert Gemini Extension to Claude

User: "Port my Gemini extension to Claude Code"
Claude: I'll convert this Gemini extension to a Claude skill...
- Detected Gemini extension (found gemini-extension.json)
- Extracted manifest and context file
- Generated SKILL.md with YAML frontmatter
- Created .claude-plugin/marketplace.json
- Converted excludeTools to allowed-tools
✓ Conversion complete! Install with: cp -r ./extension ~/.claude/skills/

Create Universal Extension

User: "Make this skill work on both platforms"
Claude: I'll create a universal extension structure...
- Analyzing current configuration
- Generating both Claude and Gemini files
- Moving shared content to shared/ directory
- Updating MCP server paths for both platforms
✓ Universal extension created! Works with both Claude Code and Gemini CLI

Advanced Features

Pull Request Generation

Create a PR to add dual-platform support to the parent repository:

Example requests:

"Convert this skill and create a PR to add Gemini support"
"Generate a pull request with the universal version"

Fork and Dual Setup

Create a fork with both platform configurations:

Example requests:

"Fork this repo and set it up for both platforms"
"Create a dual-platform fork I can use with both CLIs"

Validation Only

Check compatibility without converting:

Example requests:

"Validate this skill's conversion to Gemini"
"Check if this extension can be ported to Claude"
"What needs to change to make this universal?"

Configuration

This skill operates directly on filesystem directories and doesn't require external configuration. It uses:

File system access to read and write skill/extension files
Git operations for PR and fork features
GitHub CLI (gh) for repository operations

Safety Features

Non-destructive: Creates new files, doesn't modify source unless explicitly requested
Validation: Checks output before completion
Reporting: Clear summary of changes made
Rollback friendly: All changes are standard file operations

Limitations

Some aspects may require manual review:

Custom slash commands (platform-specific syntax)
Complex MCP server configurations with multiple servers
Platform-specific scripts that don't translate directly
Edge cases in tool restriction mapping

These will be flagged in the conversion report.

Technical Details

Tool Restriction Conversion

Claude → Gemini (Whitelist → Blacklist):

Analyze allowed-tools list
Generate exclude patterns for all other tools
Special handling for wildcard permissions

Gemini → Claude (Blacklist → Whitelist):

List all available tools
Remove excluded tools
Generate allowed-tools list

Settings Inference

When converting Claude → Gemini, environment variables in MCP config become settings:

javascript

// MCP env var
"env": { "DB_HOST": "${DB_HOST}" }

// Becomes Gemini setting
"settings": [{
  "name": "DB_HOST",
  "description": "Database host",
  "default": "localhost"
}]

Path Transformation

Claude uses relative paths, Gemini uses variables:

javascript

// Claude
"args": ["mcp-server/index.js"]

// Gemini
"args": ["${extensionPath}/mcp-server/index.js"]

For implementation details, see the repository at https://github.com/jduncan-rva/skill-porter

Files

SKILL.md and 49 other files in the repository root of jduncan-rva/skill-porter.

SKILL.md
.claude-plugin/marketplace.json
.gitignore
CONTRIBUTING.md
GEMINI.md
LICENSE
README.md
TEST_RESULTS.md
examples/README.md
examples/api-connector-gemini/GEMINI.md
examples/api-connector-gemini/gemini-extension.json
examples/before-after/api-connector-converted/.claude-plugin/marketplace.json
examples/before-after/api-connector-converted/GEMINI.md
examples/before-after/api-connector-converted/SKILL.md
examples/before-after/api-connector-converted/gemini-extension.json
… and 35 more

Open the folder on GitHubat commit 7ad93ec

Compare with similar skills

Skill Porter next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Skill Porter compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Skill Porter this skilljduncan-rva/skill-porter	191	—	~2k	Automated safety check: Notes	MIT	10 mo ago
MCP Server Builderanthropics/skills	180k	63 repos	~2.3k	Automated safety check: Pass	Apache-2.0	2 days ago
MCP Server BuildershareAI-lab/learn-claude-code	78k	4 repos	~1.2k	Automated safety check: Pass	MIT	13 days ago
MCP Integration for Pluginsanthropics/claude-plugins-official	38k	11 repos	~3.1k	Automated safety check: Pass	Apache-2.0	today
MemPalace Memory SearchMemPalace/mempalace	60k	—	~1.4k	Automated safety check: Pass	MIT	today
Crush Configurationcharmbracelet/crush	29k	—	~3.7k	Automated safety check: Pass	Custom licence	today

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Works with

Model Context Protocol

Questions about Skill Porter

What does Skill Porter do?

Converts Claude Code skills to Gemini CLI extensions and vice versa. Skill Porter is an agent skill from jduncan-rva/skill-porter. Converts Claude Code skills to Gemini CLI extensions and vice versa.

When should I use Skill Porter?

Skill Porter fits situations like: the user wants to make a skill cross-platform compatible; port a skill between platforms; create a universal extension that works on both Claude Code and Gemini CLI.

How do I install Skill Porter in Claude Code?

Run `npx skills add jduncan-rva/skill-porter --skill skill-porter -a claude-code`. Or copy the skill folder (the jduncan-rva/skill-porter repository) into .claude/skills/skill-porter in your project. Claude Code loads it when a task matches its description.

How do I install Skill Porter in Codex?

Run `npx skills add jduncan-rva/skill-porter --skill skill-porter -a codex`. Or copy the skill folder (the jduncan-rva/skill-porter repository) into .agents/skills/skill-porter in your project. Codex loads it when a task matches its description.

Can I use Skill Porter in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add jduncan-rva/skill-porter --skill skill-porter -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/skill-porter, .gemini/skills/skill-porter, .github/skills/skill-porter and .opencode/skills/skill-porter in your project.

What does Skill Porter need to run?

SKILL.md names no scripts, command-line tools or credentials: Skill Porter is instructions for the agent only. Its frontmatter pre-approves these tools: Read, Write, Edit, Glob, Grep, Bash.

Does Skill Porter access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Skill Porter safe to install?

Our automated static check of SKILL.md found notes only (pre-approves every shell command (allowed-tools: bash)), nothing it rates as a warning. It is not a guarantee. Review the folder before installing.

What licence does Skill Porter use?

Skill Porter is published under the MIT licence (from the LICENSE file in the skill folder). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Skill Porter use?

About 2k tokens (SKILL.md is roughly 8.1k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Skill Porter?

Skills that share tags, products or a category with Skill Porter: MCP Server Builder (anthropics/skills, 180k stars), MCP Server Builder (shareAI-lab/learn-claude-code, 78k stars), MCP Integration for Plugins (anthropics/claude-plugins-official, 38k stars) and MemPalace Memory Search (MemPalace/mempalace, 60k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Skill Porter?

jduncan-rva (a GitHub user) maintains it in jduncan-rva/skill-porter, which has 191 GitHub stars. The repository was last updated on December 2, 2025.

Source: jduncan-rva/skill-porter on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Skill Porter

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Skill Porter - Cross-Platform Skill Converter

Core Capabilities

Bidirectional Conversion

Smart Platform Detection

Metadata Transformation

MCP Server Preservation

Validation & Quality Checks

Conversion Process

Platform Differences Handled

File Structure

Metadata Format

Tool Restrictions

Configuration

MCP Server Paths

Usage Examples

Convert Claude Skill to Gemini

Convert Gemini Extension to Claude

Create Universal Extension

Advanced Features

Pull Request Generation

Fork and Dual Setup

Validation Only

Configuration

Safety Features

Limitations

Technical Details

Tool Restriction Conversion

Settings Inference

Path Transformation

Files

Compare with similar skills

Similar skills

MCP Server Builder

MCP Server Builder

MCP Integration for Plugins

MemPalace Memory Search

Crush Configuration

Context Mode Output Sandbox

Related

Questions about Skill Porter