Add Alpaca’s official MCP server to community servers list

[idsts2670]

Add Alpaca’s MCP server to community servers list

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Description

This pull request adds Alpaca’s official MCP server to the community servers list in the README. It follows the existing format and styling so contributors can quickly find and leverage Alpaca’s server for algorithmic trading workflows.

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Server Details

• Server: GitHub
• Changes to: README.md (third-party/community servers section)

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Motivation and Context

Many traders and developers want a low-code way to interact with Alpaca’s Trading API directly from AI tools. By listing Alpaca’s MCP server here, we:

• Surface a fully supported, developer-first integration for stocks and options trading.
• Help newcomers discover how to analyze market data, build strategies, and place orders algorithmically using plain English.
• Maintain consistency with other community entries, making it easy for AI platform/IDE users (Claude, VS Code, Cursor, etc.) to find and adopt this server.

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How Has This Been Tested?

• Verified that the README update renders correctly in GitHub’s Markdown preview.
• Confirmed that the link points to the correct repository (alpaca-mcp-server).
• Ran a sample query via Claude Desktop and Cursor against Alpaca’s MCP server to ensure all the endpoints respond (e.g., "Get current account balance").

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Breaking Changes

• None. This is purely a documentation update; no MCP client configuration changes are required.

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Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [x] Documentation update (adds new server listing)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

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Checklist

• [x] I have read the [MCP Protocol Documentation](https://modelcontextprotocol.io)
• [x] My changes follow MCP security best practices
• [x] I have updated the server’s README accordingly
• [x] I have tested this with an LLM client (e.g., Claude Desktop)
• [x] My code (or docs) follows the repository’s style guidelines
• [x] New and existing tests pass locally
• [x] I have added appropriate error handling (N/A for docs)
• [x] I have documented all environment variables and configuration options (N/A for docs)

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Additional context

This entry should appear alphabetically under the “Community Servers” section, immediately after any server whose name begins with “Al…” (e.g., “Alloy”). If this section grows, it may be helpful to split servers by category (e.g., “Finance,” “Productivity”) in the future.