Custom Skills vs Marketplace Skills in Claude Code - Why Building Your Own Wins
Custom Skills vs Marketplace Skills in Claude Code
After months of using Claude Code daily, we ended up with mostly custom skills written for specific recurring tasks. The official marketplace skills are hit or miss. Here is why.
The Marketplace Problem
Marketplace skills are built for general use cases. They have to work for everyone, which means they work perfectly for no one. A generic "deploy to production" skill cannot know your specific CI pipeline, your environment variable naming convention, or your team's deployment checklist.
The result is that marketplace skills either:
- Do too little. They handle the happy path and leave you to deal with every edge case manually.
- Do too much. They try to be comprehensive and end up adding complexity you do not need.
- Make assumptions. They assume a specific stack, directory structure, or workflow that does not match yours.
Why Custom Skills Win
A custom skill is a markdown file that encodes your exact workflow. It knows:
- Your project's specific file structure and naming conventions
- The exact sequence of commands for your deployment pipeline
- Which files to check, which tests to run, which logs to tail
- Your team's code review checklist and PR template
For example, our send-fazm-email skill knows to use a specific Python script with curl-based HTTP requests (because Cloudflare blocks Python's default user agent), the correct Resend API endpoint, and our domain's verified sender address. No marketplace skill would encode that level of specificity.
The 80/20 Split
In practice, about 80% of the skills we use daily are custom-built. The remaining 20% from the marketplace are genuinely general-purpose - things like "format this code" or "explain this error."
The pattern that works:
- Start with marketplace skills for common tasks.
- Notice where they fall short for your specific workflow.
- Fork or rewrite them as custom skills with your exact requirements.
- Iterate as your workflow changes.
Building Custom Skills for Agents
The same principle applies to building Fazm. Generic automation templates are a starting point, but the real value comes when the agent learns your specific workflows and builds custom execution patterns around them.
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- Claude MD and MCP Server Integration
Fazm is an open source macOS AI agent. Open source on GitHub.