Goose: The Open Source Agent by Block (2026 Review)

Rating: 9.0/10 (Best Open Source CLI Agent)

1. Executive Summary

Goose is an open-source AI agent developed by Block (Square). It is designed to be an extensible, developer-focused agent that runs in your terminal or on your desktop. Unlike closed-source agents, Goose is built to be hacked on and extended via the Model Context Protocol (MCP).

2. Core Features

2.1 Model Context Protocol (MCP) Support

• Extensibility: Goose can be extended with "tools" that allow it to interact with any API, database, or local application.
• Community Tools: A growing ecosystem of MCP servers allows Goose to control Slack, Jira, GitHub, and more.

2.2 Local & Secure

• BYOK (Bring Your Own Key): You use your own API keys for LLMs.
• Local Execution: Goose runs locally, giving it full access to your filesystem and local tools (with your permission).

3. Pros & Cons

Pros

• Fully Open Source: MIT licensed.
• MCP Ecosystem: Unlimited potential for integration.
• Backed by Block: Strong engineering support.

Cons

• UI: Primarily CLI/Desktop focused, less visual than some IDE agents.
• Setup: Requires more technical know-how than a "one-click" SaaS tool.

5. Conclusion

Goose is the hacker's agent. If you want to build your own AI workflows and integrations, Goose provides the perfect foundation.