Semlith 0.21.0

On 2026-09-17 a session opened with no semlith server. The registration was
correct, at user scope, and the installed binary answered initialize in well
under a second over six stores. It happened again on 2026-09-18. Nothing
anywhere said why.

The cause was found before a line of this release was written: ~/.claude.json
held projects["…/live/semlith"].disabledMcpjsonServers containing semlith.
The server was registered and switched off for one directory. claude mcp list
run from anywhere else reported it connected, so every check short of asking
from the affected directory passed.

This release is about that class of failure — semlith absent, with nothing
saying so — from every side it can be reached.

semlith is there before a client asks

• semlith start --service installs the daemon as a login service: a launchd
  user agent on macOS, a systemd user unit on Linux, a logon task on Windows.
  It runs from the next login onwards, and on macOS and Linux a daemon that
  exits is restarted within seconds with nobody present. semlith start --no-service removes it and leaves a running daemon and every store exactly
  as they are.
• semlith setup and the installers install it, including where nothing can
  answer a prompt — a piped installer, CI, --yes. A user who never reads the
  prompt is the user a login service is for. --no-service opts out, and so
  does SEMLITH_NO_SERVICE=1, which both install scripts and semlith setup
  itself read — so a provisioning script gets the same answer whichever of them
  it reaches for. Installing semlith now starts a daemon, so anything that
  wants to run its own should opt out; that is what the harness does.
• Installing onto a port something already holds registers the service for the
  next login and leaves the running daemon alone. Starting a second one would
  lose the bind and exit, and KeepAlive would start it again.
• On macOS, a binary inside ~/Documents, ~/Desktop, ~/Downloads or iCloud
  Drive is refused rather than installed. A launchd agent pointing at one
  installs cleanly, reports a live pid, and then stops inside the dynamic
  linker before it can write a word to its own log: no error, no timeout, no
  port. The refusal names the directory and where to install instead.

The handshake no longer waits for the embedding model

• semlith mcp answers initialize and tools/list before any model is
  loaded. It used to load every distinct model first, so a client's startup
  timeout could expire on an ONNX session or a model download and report no
  server at all. The model now loads on a background thread; only a tool call
  that needs it waits. The tool list is byte-identical to 0.20.2's.
• A machine with nothing indexed gets a server instead of an exit code. A fresh
  install wired into a client used to end the process with "no semlith store
  covers …" before writing a byte of protocol. The tools are listed, and the
  first call that needs a corpus carries the message that used to be fatal.
• semlith mcp no longer claims a privacy rejection for a file that is not
  there. Every start printed one line per store — six on the machine this was
  found on — saying daemon.json "is not a file this user wrote privately",
  naming paths that answer No such file or directory. Those lines were the
  first thing in a client's log for anyone debugging an absent server.

semlith doctor names the step that failed

• A server registered at user scope and switched off for one directory is
  reported as a fault in that directory, naming the file, the key and the
  directory, with the command that turns it back on. It is never re-enabled
  without being asked: switching a server off is a choice, and naming it is
  semlith's job. From any other directory the row is green and still says which
  directory it is off in.
• Every registration semlith writes names the resolved absolute path of the
  binary rather than the bare command semlith. A bare command launches only
  from a PATH that happens to carry the binary, and the PATH a login shell
  builds is not the one a service manager hands a job.

Housekeeping

• The native smoke harness on all three platforms installs the login service,
  kills the daemon and confirms it comes back, and checks that the handshake
  answers with the embedding model made impossible to load.

Install

macOS and Linux

curl -fsSL https://raw.githubusercontent.com/semlith/semlith/main/install.sh | sh

Windows

irm https://raw.githubusercontent.com/semlith/semlith/main/install.ps1 | iex

Or download the archive for your platform below, unpack it, and put
semlith on your PATH. Intel macOS has no prebuilt binary: ONNX
Runtime no longer publishes x86_64 macOS builds.

Verify a download against SHA256SUMS before running it.