Gemini CLI Skills: How Agent Skills Fit the Workflow
Gemini CLI Skills: How Agent Skills Fit the Workflow
Gemini CLI Skills are on-demand instruction packages for agents. They are valuable, but they are not MCP servers. Understanding the difference helps you build better AI-assisted workflows.
What Are Gemini CLI Skills?
A Gemini CLI Skill is a SKILL.md file that an agent loads on demand. It packages:
- Step-by-step procedural instructions
- Domain-specific context and terminology
- Checklists and decision trees
- Examples of correct behavior for a task
Skills tell the agent how to think about a problem. They are loaded into the agent's context window at runtime and do not expose any tools or API endpoints.
Official Sources
- Official docs: Agent Skills in Gemini CLI
- Repository examples: google-gemini/gemini-skills
- Built-in examples in google-gemini/gemini-cli
Skills vs MCP Servers: Key Differences
| Aspect | Gemini CLI Skill | MCP Server |
|---|---|---|
| Format | SKILL.md markdown file | Running process with JSON-RPC |
| What it provides | Instructions and context | Tools, resources, prompts |
| Requires network? | No | Depends on server |
| Exposes API? | No | Yes |
| Installed how? | File in skills directory | Configured in mcp.json |
| Invoked by | Agent reads file | Agent calls tool |
| Good for | Checklists, workflows, domain knowledge | Database queries, API calls, file access |
When to Use Skills
Use a Gemini CLI Skill when:
- You want to teach the agent a repeatable process (code review checklist, deployment steps)
- You need domain-specific terminology loaded into context
- You want consistent behavior across sessions without modifying the system prompt
- The task requires judgment, not API access
When to Use MCP Servers Instead
Use an MCP server when:
- The agent needs to read or write external data (databases, files, APIs)
- You need real-time information (stock prices, weather, GitHub issues)
- You want the agent to take actions in external systems (create PRs, send messages)
- You need structured tool calls with typed inputs and outputs
Using Skills Alongside MCP
Skills and MCP servers are complementary. A skill can instruct the agent on how to use an MCP server correctly — for example, a "database query" skill might contain guidelines for constructing safe SQL queries that the agent then executes via a database MCP server.
Finding MCP Servers for Gemini CLI
Browse aimcp.info to find MCP servers that work with Gemini CLI, including servers for GitHub, file systems, databases, and more.