# Browser clients reach the AgentOS MCP server through CORS

> Agno AgentOS now admits any browser origin its CORS policy allows on `/mcp` and `/mcp/server-card`, so os.agno.com can read the MCP server of a local AgentOS.

- Published: 2026-10-22
- Author: Yash Pratap Solanky
- Categories: Changelog
- Canonical: https://www.agno.com/blog/browser-clients-reach-the-agentos-mcp-server-through-cors
- Markdown: https://www.agno.com/blog/browser-clients-reach-the-agentos-mcp-server-through-cors.md

Agno AgentOS now runs a browser `Origin` on `/mcp` and `/mcp/server-card` through the same CORS policy as its REST routes, which by default includes the Agno domains. A default local AgentOS already answered `GET /config` from `https://os.agno.com`, yet refused the MCP routes from that same page:

```text
# Earlier releases, default local AgentOS
GET  /mcp/server-card  Origin: https://os.agno.com   400 {"error":"invalid_origin","detail":"Origin not allowed."}
POST /mcp initialize   Origin: https://os.agno.com   400 {"error":"invalid_origin","detail":"Origin not allowed."}

# This release
GET  /mcp/server-card  Origin: https://os.agno.com   200
POST /mcp initialize   Origin: https://os.agno.com   200
GET  /mcp/server-card  Origin: https://evil.example  400 {"error":"invalid_origin","detail":"Origin not allowed."}
```

An origin outside the policy is still refused, and `allowed_hosts` works as before. `/info` also reports the MCP path you configured, so `MCPConfig(path="/ai/mcp")` now shows `"path": "/ai/mcp"` where earlier releases always said `/mcp`. Both captures come from FastAPI's `TestClient` on each release.

Learn more about [transport security on the AgentOS MCP server](https://docs.agno.com/agent-os/mcp/mcp#transport-security) in the documentation.