sneg

antono's personal Nix package set — the custom packages used by my personal NixOS/home-manager flake, in one repo instead of one fork per project.

Use it

{
  inputs.sneg = {
    url = "github:antono/sneg";
    inputs.nixpkgs.follows = "nixpkgs";
  };
}

Then either take the overlay, which makes everything available as pkgs.<name>:

nixpkgs.overlays = [ inputs.sneg.overlays.default ];

or reach for a single package directly:

inputs.sneg.packages.${system}.deplexity

Packages

Attribute	What
deplexity	Export Perplexity AI conversations, spaces and profile to JSON/Markdown/PDF
deplexity-with-chromium	Same, bundling Chromium so deplexity login works out of the box (linux only)
tolaria	Tolaria desktop app bundled with its MCP server (linux only — WebKitGTK 4.1)
tolaria-mcp	Just the Tolaria MCP server: vault tools over stdio + a WebSocket bridge
tolaria-node-modules	Tolaria's pnpm dependency closure, exposed so the hash can be rebuilt on its own
tolaria-src	Tolaria's fetched source, exposed so it can be realised on its own
hacktv	Analogue TV signal generator for SDR hardware
mcphub	Self-hosted MCP gateway: fronts many MCP servers behind one endpoint, with a dashboard
argocd-mcp	MCP server for Argo CD
blender-mcp	MCP server for Blender (pairs with an extension installed into Blender)
freecad-mcp	MCP server for FreeCAD (pairs with an addon installed into FreeCAD)
greenhouse-mcp	MCP server for the Greenhouse Harvest API
kicad-mcp	MCP server for KiCAD (wraps a KiCAD install: its pcbnew bindings, CLI and libraries)
konnect	MCP server for KiCAD 10, the Rust rewrite of the above — one binary, over KiCAD's IPC API
mcp-musescore	MCP server for MuseScore (pairs with a QML plugin)
signoz-mcp-server	MCP server for SigNoz

MCP servers

The servers above are the ones mcp-servers-nix does not ship. There is no fork of it: sneg's servers plug into upstream's module system, and lib.mkConfig is a drop-in for upstream's that knows about both sides.

programs.mcp.configFile = inputs.sneg.lib.mkConfig pkgs {
  programs = {
    # from mcp-servers-nix
    chrome-devtools.enable = true;
    context7.enable = true;
    nixos.enable = true;
    playwright.enable = true;
    terraform.enable = true;

    # from sneg
    argocd = {
      enable = true;
      baseUrl = "https://argocd.example.com";
      passwordCommand.ARGOCD_API_TOKEN = [ "cat" "/run/secrets/argocd" ];
    };
    signoz.enable = true;
  };
};

Secrets go through envFile or passwordCommand, never env or args — everything in /nix/store is world-readable. That is why sneg's modules expose hosts and URLs as options but never tokens.

Prefer upstream's version of a server whenever it gains one: when chrome-devtools landed there, sneg's copy was deleted rather than kept.

The two KiCAD servers are the ones that are not self-contained: both wrap a pkgs.kicad of their own, because kicad-cli and the KICAD<major>_*_DIR library paths are otherwise set only by the kicad wrapper, which nothing here runs under. kicad-mcp needs more of it — pcbnew is a compiled module that ships inside kicad rather than in nixpkgs' python set, so the interpreter is wrapped too. Each has a README beside its package, and .override { kicad = ...; } moves everything together.

They are alternatives, not duplicates: konnect is the author's Rust rewrite — AGPL-3.0, KiCAD 10 only, one binary over the IPC API — while kicad-mcp stays MIT and works against 8 and 9. Enabling both is fine.

How the composition works

Upstream's lib.evalModule takes the nixpkgs instance it resolves server packages from, plus one module. Both are seams:

• extending nixpkgs with overlays.mcp-servers makes programs.<name>.package resolve sneg's servers by name, exactly as it resolves upstream's;
• the module can imports sneg's server modules, which are ordinary mcp-servers-nix modules built on upstream's mkServerModule specialArg.

lib/default.nix does both. If you would rather wire it yourself:

inputs.mcp-servers-nix.lib.mkConfig (pkgs.extend inputs.sneg.overlays.mcp-servers) {
  imports = inputs.sneg.lib.serverModules;
  programs.signoz.enable = true;
}

checks.<system>.mcp-servers renders every server from both sides into one config file, so a bad package name or a clash with an upstream module fails here rather than at the consumer.

The hub

mcphub is not another server. It is a gateway: it starts the servers listed in its settings file and re-exports all of them over one HTTP origin — with a dashboard, bearer keys and a CLI on top — so a client that cannot spawn stdio children gets a single stable address instead of N processes of its own.

homeManagerModules.mcphub runs it as a user service (systemd on linux, launchd on darwin):

{
  imports = [ inputs.sneg.homeManagerModules.mcphub ];

  # Declared once. Direct clients read this; so does the hub.
  programs.mcp.servers.nixos = { ... };

  services.mcphub = {
    enable = true;

    # Servers only the hub should see, in mcphub's own schema. Merged after
    # programs.mcp, so a name repeated here wins.
    servers.deploy-notes = {
      type = "streamable-http";
      url = "https://notes.example.com/mcp";
      # Expanded by mcphub from its own environment, so the token itself never
      # reaches the store.
      headers.Authorization = "Bearer \${NOTES_TOKEN}";
    };

    environmentFile = "/run/secrets/mcphub.env";
  };
}

The thing to understand about mcphub is that it owns its settings file. There is exactly one — mcp_settings.json — and mcphub does not merely read it: the admin password hash lands there on first boot, every bearer key and OAuth client the dashboard mints is appended to it, and every server toggled in the UI is written back. A store symlink fails on the first write; a file regenerated on every home-manager switch throws away the credentials that make the dashboard reachable.

So the module treats it as state and merges into it at every start, under one rule: every top-level key the module declares replaces that key in the live file, and every key it does not declare is left alone. servers and useHomeManagerServers declare mcpServers; settings declares whatever it names. users, bearerKeys, groups, oauthClients, oauthTokens, prompts and resources therefore survive untouched — and mcpServers, once declared, is declared entirely, so a server added through the dashboard is dropped at the next restart. Declare nothing and the dashboard owns the list.

The merge is shallow on purpose. A recursive one would leave half-overwritten systemConfig subtrees matching neither what Nix said nor what the dashboard said, so settings.systemConfig must be restated whole. It is a jq program in its own store file, which is what lets checks.<system>.mcphub-module run it against fabricated inputs rather than grepping the shell command that invokes it.

useHomeManagerServers (on by default) folds ~/.config/mcp/mcp.json in as the first source of servers, read when the service starts rather than when the configuration is built. The two schemas line up better than the names suggest: type, command, args, env, url, headers and — unlike the hub this replaced — enabled all mean the same thing on both sides, so a server switched off in programs.mcp is switched off in the hub too.

The one thing that does not survive the trip is env.<VAR>.file, which home-manager renders as the literal string {file:/path} for its per-client modules to rewrite. mcphub has no such placeholder and hands the token text to the server as its secret. That warns. The fix is to restate the server under services.mcphub.servers with env.<VAR> = "${VAR}": mcphub expands ${VAR} and $VAR from its own environment across a server's env, args, headers and url, so supplying the variable through environmentFile keeps the secret out of the store — the same rule the server modules follow, and the reason environment is the wrong place for one.

mcphub is configured by environment variable rather than by argument: the module exports PORT, BASE_PATH and MCPHUB_SETTING_PATH itself and leaves the rest — ADMIN_PASSWORD, DISABLE_WEB, READONLY, the timeouts — to environment and environmentFile. Note that it binds every interface, with no upstream option to narrow that, and that settings.systemConfig.routing.skipAuth turns every caller on that port into an admin who can register a stdio server. The module warns about the second; the first is on you.

New generations reach a running hub by restarting it. The start script carries the whole configuration in its own store path, so the unit's ExecStart and the agent's ProgramArguments differ whenever anything does — that is enough for sd-switch on linux and for home-manager's plist comparison on darwin, with no generation marker needed. Unit.X-Restart-Triggers covers the one input that is not baked in: the servers home-manager writes to a stable ~/.config path. mcphub re-reads its settings when the mtime moves, but the merge that moves it runs at start, so the restart is the reload.

This module is independent of homeManagerModules.default — the bridge writes programs.mcp.servers, the hub merges the file that option generates — so importing both is fine and is the normal case: the bridge feeds sneg's servers into programs.mcp, and the hub picks them up from there.

modules/mcphub.nix        the service module
pkgs/mcphub/package.nix
tests/mcphub-module.nix   checks.<system>.mcphub-module — the rendered unit,
                          the start script, and the merge rule actually run

Layout for MCP servers

lib/default.nix                mkConfig / evalModule / serverModules
modules/mcp-servers/<name>.nix one file per server, auto-discovered
pkgs/mcp-servers/<name>/package.nix
tests/mcp-servers.nix          the composition check

Package attribute names must match the packageName its module passes to mkServerModule — that is the only thing tying the two halves together.

One caveat: tolaria evaluates via import-from-derivation

crane reads tolaria's Cargo.lock and Cargo.toml out of the fetched tree, so merely evaluating tolaria requires its source to already be in the store. Upstream's flake avoids this only because its src is a local path.

Consequences, all of them handled in .github/workflows/ci.yml:

• nix flake check --no-build cannot instantiate tolaria on a cold store. Run nix build --no-link .#tolaria-src first.
• --all-systems cannot work: evaluating packages.aarch64-* would need an aarch64 source derivation realised on an x86_64 machine.

Layout

flake.nix              packages.<system>.*, overlays.default, checks, devShell
overlay.nix            final: _prev: import ./pkgs final
pkgs/default.nix       the package list — one line per package
pkgs/<name>/package.nix

pkgs/default.nix is the single source of truth: overlays.default and packages.<system> are both derived from it.

A package that ships several outputs from one source tree (tolaria) gets a directory with a default.nix returning a set, which pkgs/default.nix splices into the package set under its final names.

Two rules the overlay has to obey:

• Anything deciding which attributes exist must read prev, not final. Reading final.stdenv there sends the nixpkgs stdenv bootstrap into infinite recursion.
• Extra flake inputs (fenix, crane — both only for tolaria) reach packages through the inputs argument threaded from flake.nix via overlay.nix. Prefer packages that need nothing beyond nixpkgs.

Add a package

1. pkgs/<name>/package.nix — a plain callPackage-able derivation. Keep it nixpkgs-shaped (fetchFromGitHub pinned to a release tag, no local paths, no flake inputs) so it can be sent upstream as-is later.
2. One line in pkgs/default.nix.
3. git add it — flakes ignore untracked files — then nix flake check -L.

Starting from scratch? nix run nixpkgs#nix-init -- pkgs/<name>/package.nix generates a first draft.

Bump a package

nix-update --flake deplexity     # rewrites version, src hash and vendorHash
nix flake check -L

Develop

nix develop          # nix-update, nix-init, nixfmt-tree
nix fmt
nix build .#deplexity && ./result/bin/deplexity version