MCP open_url gotchas
Why Rig refuses the wrong localhost.
Rule
open_url requires a Rig project_id (or project-scoped token) and prefers that project’s detectedPort.
Refusal
If a URL is owned by another project’s pid/cwd, Rig won’t open it — by design since beta.31.
See also
Related
- Project-scoped MCP
- Ports, crashes, and reclaim
- Ports and conflicts in local development
- MCP for coding agents: servers, config files, and tokens
- Port in use command generator
- Local dev port planner
- Find what is using a port and free it
- localhost vs 127.0.0.1 vs 0.0.0.0
- AI & MCP guides
- MCP in Rig
- What is MCP?
- Connect Cursor