Semlith Files

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

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

Windows

:::powershell
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.