Root-caused two real issues Rune hit with Obsidian/Homepage external MCP
servers:
1. Toggling a server's enable switch silently wiped transportKind/env/
url/bearerToken/headers back to stdio defaults (only id/name/command/
args/isEnabled/timeout/createdAt were preserved) — almost certainly
how Obsidian's config got corrupted into an empty-command stdio entry
despite never being edited directly. Fixed via
ExternalMCPServer.withEnabledToggled(), which flips only isEnabled.
2. npx (installed via Homebrew) was invisible to Confab because GUI apps
only inherit launchd's minimal PATH, not the Terminal PATH. Tried
spawning the user's login shell to ask for its real PATH — this
caused two real hangs in one session (first an -ilc pipe deadlock,
then a waitUntilExit()/CFRunLoop reentrancy issue even after fixing
that) and was abandoned entirely in favor of LoginShellEnvironment:
deterministic, subprocess-free directory probing (Homebrew, MacPorts,
Volta, nvm's alias file) that can't hang by construction.
Also added:
- Edit capability for existing External MCP servers (previously only
Add/Toggle/Delete) — the second thing Rune explicitly asked for, and
the way to fix a corrupted entry like Obsidian's without deleting it.
- MCPClientError.commandNotFound: a stdio server's command is checked
against PATH up front in StdioMCPTransport.prepare() and fails
immediately with a clear reason instead of cycling through 3 rounds of
crash/restart backoff (5s/15s/30s) for a permanently-missing binary.
- A "Get Node.js" button appears when this happens, opening a sheet with
a copyable `brew install node`, a one-click install (via
NodeInstallHelper, using the terminationHandler/readabilityHandler
pattern already proven safe elsewhere in this file — deliberately not
waitUntilExit()), or a nodejs.org link if Homebrew isn't present.
- ExternalMCPManager.retryClient(id:) to manually retry after fixing the
underlying cause.
- Help book: new "Servers That Use npx" section, updated Server Status
section, updated Settings blurb.
37 new/changed tests covering the toggle fix, PATH probing, the
commandNotFound fast-fail path, and missing-command detection — full
suite (374 tests) passes clean.
