[FEATURE] Human-readable error banners for Claude-Desktop extensions

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Summary

When an MCP extension fails to connect, Claude Desktop displays a red banner with a generic message like
"Could not attach to MCP server X" or "Server disconnected." These messages are not actionable. The app
has enough context at the time of failure to display something useful — it just doesn't.

Examples encountered (Claude Desktop 1.1.3963, Windows 11)

1. Windows-MCP / Android-MCP — missing uv binary

Shown: MCP Windows-MCP: spawn uv ENOENT
Should say: Windows-MCP requires uv (Python package runner). Install it: winget install astral-sh.uv

The fix is a single command. The error message already contains the binary name — just wrap it.

1. Windows-MCP / Android-MCP — first-run venv build timeout

Shown: Could not attach to MCP server Windows-MCP / Server disconnected
Should say: Windows-MCP is building its environment for the first time. This takes ~60 seconds. Please
wait and relaunch.

The app can see uv is running and installing packages. It should not fire a fatal error banner while a
known install process is in progress. This caused unnecessary reinstall attempts.

1. Android-MCP — no device connected

Shown: Could not attach to MCP server Android-MCP / Server disconnected
Should say: Android-MCP requires an Android device connected via USB with ADB debugging enabled, or a
running emulator (emulator-5554).

The traceback is right there in the log: ConnectError: device emulator-5554 not online. Surface it.

1. Claude in Chrome — extension not running

Shown: Could not connect to MCP server Claude in Chrome
Should say: Claude in Chrome requires the Chrome extension to be installed and running. Get it from the
Chrome Web Store.

1. mcp-registry — remote API unreachable

Shown: Could not connect to MCP server mcp-registry
Should say: Could not reach the MCP registry (DNS/network). Check your connection or VPN configuration.

Proposed Solution

1. Parse stderr/exit codes from MCP server processes and map known patterns to plain-English messages
2. Distinguish between fatal errors (red banner, action required) and transient states (first-run

install, brief disconnects) — the latter should show a spinner or info notice, not a fatal banner

1. For extension-type errors, link to the extension's documentation page

Alternative Solutions

_No response_

Priority

not sure why this defaulted to prioritty critical, that has to be a headache on your end. It did temporarily inhibit further development, but then I spent tokens debugging your code, as I'm sure others have.

Feature Category

CLI commands and flags

Use Case Example

Users currently have no idea whether a red banner means "broken install," "missing device," "missing
browser extension," or "background network call failed." All four look identical. This creates
unnecessary support burden and makes the extension ecosystem feel unreliable when the individual
extensions are working correctly.

Additional Context

_No response_