Start with rdc doctor on the machine being controlled. It checks each layer in order and says
which one failed.
Message Meaning Fix
allowlist is emptyno --allow and no [serve].allow add at least one entry X is not a Tailscale address; refusing--bind or config points at a LAN/public IPbind the Tailscale IP or leave bind unset tailscaled unreachable / no Tailscale IPTailscale not running or not logged in tailscale status; on macOS make sure the Tailscale app is running in the same user sessionbind … Address already in useanother rdc or something else on 7770 --port
Symptom Cause Fix
connection refused / timeout daemon not running, wrong host, you’re not on the tailnet, or the Tailscale policy blocks tcp/7770 tailscale ping HOST; check rdc service status on the target; add a policy rule for tcp:7770 (see Configuration )403 … is not in the allowlistwhois succeeded but you’re not allowed add your login/node/tag; rdc -t HOST whoami shows what the daemon sees once allowed, the 403 message shows it when not 403 … is not a Tailscale addressrequest arrived from a non-tailnet IP use the Tailscale hostname or 100.x address 403 forbidden: … may not use \input``your grant is limited to some capabilities widen can in the grant on the daemon side; rdc -t HOST whoami shows your caps 403 loopback connections are not acceptedyou’re on the same machine use --target local, or start the daemon with --dev-loopback for testing 421 request addressed to unexpected hostthe URL uses a name the daemon doesn’t recognise as itself use the Tailscale MagicDNS name or IP, or add the name to [serve].hosts 400 point (…) is outside the desktopcoordinates beyond the displays check rdc displays; with MCP, take a fresh screenshot 400 scroll steps must be within ±100scroll amount too large scroll in smaller steps
Symptom Cause Fix
macOS: image is only the wallpaper, windows lists 1 entry Screen Recording not granted to this exact build macOS setup : re-grant, tccutil reset, avoid ad-hoc signingmacOS: screenshots take many seconds screencapture failed and rdc fell back to CoreGraphicscheck the daemon log for screencapture failed; usually a permission problem Wayland: xcap: … error no portal backend or screencopy support install xdg-desktop-portal-<compositor>; on GNOME the portal Screenshot dialog may need approving once black image on X11 compositor/driver quirk try --display primary
Symptom Cause Fix
macOS: permission denied: Accessibility or clicks do nothing Accessibility not granted grant to rdc.app, restart daemon Wayland: no way to move the mouse compositor lacks the wlr virtual pointer protocol (GNOME, KDE) not supported yet; capture works, input does not (issue #2) clicks land in the wrong place coordinates from a stale or differently sized screenshot; or CLI given image pixels instead of desktop points take a new screenshot; use rdc mcp, or convert as in CLI reference key: "foo" is not a modifiertypo in the chord see the chord grammar in the CLI reference Windows: input ignored or focus refused for an elevated app UIPI; the daemon runs at standard integrity by default close the elevated window, or reinstall with rdc service install --elevated if you accept a permanently elevated daemon Windows: doctor shows a 1024×768 “WinDisc” display and screenshots fail you’re in an SSH or service session (session 0) run the daemon via rdc service install; test from the client machine
Symptom Fix
Claude Code shows the server as failed run rdc mcp --target NAME in a terminal; it should sit waiting on stdin with no errors. Common causes: rdc not on PATH, unknown target name, config parse error tools work but images are huge/slow rdc mcp --max 1200the agent clicks the wrong thing after a screenshot with a custom max the skill tells agents to click from the latest image; remind it
Daemon: RDC_LOG=debug rdc serve … (foreground); service logs are in journalctl --user -u dev.rdc.daemon (Linux) or ~/Library/Application Support/rdc/serve.log (macOS).
Every request is logged with the resolved identity; rejections are logged at warn.
The audit log has one line per request or rejection: rdc audit -n 100 on the daemon machine.
Client and MCP: --log debug or RDC_LOG=debug; goes to stderr, so it won’t corrupt MCP stdio.