MCP open_url gotchas

Rule

Refusal

See also

Why Rig refuses the wrong localhost.

open_url requires a Rig project_id (or project-scoped token) and prefers that project’s detectedPort.

If a URL is owned by another project’s pid/cwd, Rig won’t open it — by design since beta.31.

• Project-scoped MCP
• Ports, crashes, and reclaim

MCP open_url gotchas Why Rig refuses the wrong localhost. mcp open_url ports Rule Refusal

Related guides

• Project-scoped MCP
• Ports, crashes, and reclaim

This article is part of the Rig knowledge base at userig.app/docs. Rig is a local-first Mac app that runs, watches, and restarts development processes with unified logs, ports, and a scoped MCP hub for AI coding agents. Your source code stays on your Mac.

https://userig.app/docs/mcp-open-url