Extensions — Packaged Superpowers for Gemini CLI

# Install from GitHub URL
gemini extensions install https://github.com/example/gemini-ext-obsidian

# List all installed extensions
gemini extensions list

# Remove an extension by name
gemini extensions remove gemini-ext-obsidian

# Update all extensions to latest
gemini extensions update

# Show details about a specific extension
gemini extensions info gemini-ext-obsidian

# mcp/server.py — GitHub PR Assistant MCP server (Python variant)
import asyncio
import json
import os
import sys
import httpx
from mcp.server import Server
from mcp.server.stdio import stdio_server
from mcp import types

GITHUB_TOKEN = os.environ.get("GITHUB_TOKEN")
if not GITHUB_TOKEN:
    print("GITHUB_TOKEN environment variable is required", file=sys.stderr)
    sys.exit(1)

HEADERS = {
    "Authorization": f"Bearer {GITHUB_TOKEN}",
    "Accept": "application/vnd.github.v3+json",
    "User-Agent": "gemini-ext-github-pr/1.0",
}

server = Server("github-pr-mcp")

# ── Tool definitions ──────────────────────────────────────────────────
@server.list_tools()
async def list_tools() -> list[types.Tool]:
    return [
        types.Tool(
            name="get_pull_request",
            description="Fetch a GitHub PR including diff and file list",
            inputSchema={
                "type": "object",
                "properties": {
                    "owner": {"type": "string"},
                    "repo": {"type": "string"},
                    "pr_number": {"type": "integer"},
                },
                "required": ["owner", "repo", "pr_number"],
            },
        ),
        types.Tool(
            name="get_issue",
            description="Fetch a GitHub issue by number",
            inputSchema={
                "type": "object",
                "properties": {
                    "owner": {"type": "string"},
                    "repo": {"type": "string"},
                    "issue_number": {"type": "integer"},
                },
                "required": ["owner", "repo", "issue_number"],
            },
        ),
        types.Tool(
            name="post_pr_comment",
            description="Post a Markdown comment on a pull request",
            inputSchema={
                "type": "object",
                "properties": {
                    "owner": {"type": "string"},
                    "repo": {"type": "string"},
                    "pr_number": {"type": "integer"},
                    "body": {"type": "string"},
                },
                "required": ["owner", "repo", "pr_number", "body"],
            },
        ),
    ]

# ── Tool implementations ──────────────────────────────────────────────
@server.call_tool()
async def call_tool(name: str, arguments: dict) -> list[types.TextContent]:
    async with httpx.AsyncClient() as client:
        try:
            if name == "get_pull_request":
                owner, repo, pr_num = (
                    arguments["owner"],
                    arguments["repo"],
                    arguments["pr_number"],
                )
                pr_resp = await client.get(
                    f"https://api.github.com/repos/{owner}/{repo}/pulls/{pr_num}",
                    headers=HEADERS,
                )
                pr_resp.raise_for_status()
                files_resp = await client.get(
                    f"https://api.github.com/repos/{owner}/{repo}/pulls/{pr_num}/files",
                    headers=HEADERS,
                )
                files_resp.raise_for_status()
                result = {"pr": pr_resp.json(), "files": files_resp.json()}
                return [types.TextContent(type="text", text=json.dumps(result))]

            elif name == "get_issue":
                owner, repo, issue_num = (
                    arguments["owner"],
                    arguments["repo"],
                    arguments["issue_number"],
                )
                resp = await client.get(
                    f"https://api.github.com/repos/{owner}/{repo}/issues/{issue_num}",
                    headers=HEADERS,
                )
                resp.raise_for_status()
                return [types.TextContent(type="text", text=json.dumps(resp.json()))]

            elif name == "post_pr_comment":
                owner, repo, pr_num, body = (
                    arguments["owner"],
                    arguments["repo"],
                    arguments["pr_number"],
                    arguments["body"],
                )
                resp = await client.post(
                    f"https://api.github.com/repos/{owner}/{repo}/issues/{pr_num}/comments",
                    headers={**HEADERS, "Content-Type": "application/json"},
                    json={"body": body},
                )
                resp.raise_for_status()
                return [types.TextContent(type="text", text="Comment posted successfully.")]

            else:
                raise ValueError(f"Unknown tool: {name}")

        except Exception as e:
            return [types.TextContent(type="text", text=f"Error: {e}")]

# ── Start server ──────────────────────────────────────────────────────
async def main():
    async with stdio_server() as (read_stream, write_stream):
        await server.run(read_stream, write_stream, server.create_initialization_options())

if __name__ == "__main__":
    asyncio.run(main())

# Install from local path during development
gemini extensions install ./my-extension --dev

# Verify the extension is loaded
gemini extensions list
# Output:
#   gemini-ext-github-pr  v1.2.0  (dev)  3 skills  1 MCP server

# Test a skill
export GITHUB_TOKEN="ghp_yourtoken"
gemini
# > /pr-review 142
# > /issue-triage 56

# From your extension root directory
cd my-extension

# Validate package.json structure before submitting
gemini extensions validate

# Publish to geminicli.com gallery
gemini extensions publish

# Output:
# Validating package.json... OK
# Checking README.md... OK (1,240 words)
# Submitting to gallery...
# Published: https://geminicli.com/extensions/gemini-ext-github-pr
# Install: gemini extensions install https://github.com/yourname/gemini-ext-github-pr