diff --git a/docs/sourceos-shell-integration.md b/docs/sourceos-shell-integration.md
index b0be40a..9f365a9 100644
--- a/docs/sourceos-shell-integration.md
+++ b/docs/sourceos-shell-integration.md
@@ -11,6 +11,7 @@ This repository, `source-os`, carries the Linux realization surfaces required to
 - Nix/NixOS modules
 - profile wiring
 - machine-level integration hooks
+- derive-service runtime integration such as `docd`
 
 ## What does not belong here
 
diff --git a/docs/sourceos-shell-launcher-bridge.md b/docs/sourceos-shell-launcher-bridge.md
new file mode 100644
index 0000000..87287df
--- /dev/null
+++ b/docs/sourceos-shell-launcher-bridge.md
@@ -0,0 +1,28 @@
+# sourceos-shell launcher bridge note
+
+During the early shell rollout, launcher integration is tracked as temporary bridge work.
+
+## Routing rule
+
+Queries are routed by scope:
+
+- `apps` -> launcher or desktop-entry provider
+- `files` -> Linux-native file search only
+- `web` -> browser or web agent
+
+## Required invariant
+
+For `files` queries, Albert must not perform a second file-search pass in parallel with the Linux-native provider.
+
+## Realization scaffolds
+
+The Linux realization currently carries placeholder search-provider material at:
+
+- `linux/desktop/sourceos-search-provider.conf`
+- `/etc/sourceos-shell/search-provider.json` (realized by the shell Nix module scaffold)
+
+These capture the intended rollout mode and the provider choice for the Linux-native file search lane.
+
+## Lifecycle
+
+This bridge exists only until the shell's own command/search surface fully absorbs the routing behavior.
diff --git a/docs/sourceos-shell-service-graph.md b/docs/sourceos-shell-service-graph.md
new file mode 100644
index 0000000..e7df946
--- /dev/null
+++ b/docs/sourceos-shell-service-graph.md
@@ -0,0 +1,30 @@
+# sourceos-shell service graph note
+
+The Linux realization layer currently models the `sourceos-shell` runtime as a four-service graph:
+
+- `sourceos-shell`
+- `sourceos-router`
+- `sourceos-pdf-secure`
+- `sourceos-docd`
+
+These services are grouped by the `sourceos-shell.target` scaffold.
+
+## Intent
+
+This target is a Linux realization placeholder that captures the expected runtime grouping before the actual product/runtime repo exists.
+
+## Validation scaffold
+
+The current Linux realization adds a dedicated contract-style check at:
+
+- `tests/sourceos-shell-service-graph-contract.nix`
+
+This check verifies that:
+
+- `sourceos-shell.target` exists
+- the four runtime scaffold services are grouped beneath that target
+- the Nix module expresses the target and `partOf` relationships consistently
+
+## Follow-on
+
+Once `SourceOS-Linux/sourceos-shell` exists, the placeholder ExecStart values should be replaced with real package/service paths and the current scaffold checks should be upgraded into actual runtime/service-graph checks.
diff --git a/flake.nix b/flake.nix
index 507321e..3a9c42d 100644
--- a/flake.nix
+++ b/flake.nix
@@ -65,6 +65,9 @@
             else pkgs.runCommand "stable-x86_64-smoke-skip" {} ''
               mkdir -p $out
             '';
+
+          sourceos-shell-module-contract = import ./tests/sourceos-shell-module-contract.nix { inherit pkgs; };
+          sourceos-shell-service-graph-contract = import ./tests/sourceos-shell-service-graph-contract.nix { inherit pkgs; };
         });
 
       sourceos = {
diff --git a/linux/desktop/sourceos-search-provider.conf b/linux/desktop/sourceos-search-provider.conf
new file mode 100644
index 0000000..dc610ce
--- /dev/null
+++ b/linux/desktop/sourceos-search-provider.conf
@@ -0,0 +1,11 @@
+# SourceOS shell search-provider scaffold
+# This file records the intended launcher/search routing policy during early shell rollout.
+
+mode=launcher-bridge
+linux-file-provider=tracker3
+invariant=no_redundant_file_search
+
+# scopes
+apps=launcher
+files=linux-native-only
+web=browser-agent
diff --git a/linux/systemd/sourceos-docd.service b/linux/systemd/sourceos-docd.service
new file mode 100644
index 0000000..b34e30c
--- /dev/null
+++ b/linux/systemd/sourceos-docd.service
@@ -0,0 +1,13 @@
+[Unit]
+Description=SourceOS docd derive service
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=simple
+ExecStart=/opt/sourceos-shell/bin/sourceos-docd
+Restart=on-failure
+RestartSec=2s
+
+[Install]
+WantedBy=multi-user.target
diff --git a/linux/systemd/sourceos-shell.target b/linux/systemd/sourceos-shell.target
new file mode 100644
index 0000000..d3a2937
--- /dev/null
+++ b/linux/systemd/sourceos-shell.target
@@ -0,0 +1,4 @@
+[Unit]
+Description=SourceOS shell service graph
+Wants=sourceos-shell.service sourceos-router.service sourceos-pdf-secure.service sourceos-docd.service
+After=network-online.target
diff --git a/modules/nixos/sourceos-shell/default.nix b/modules/nixos/sourceos-shell/default.nix
index 7ae9e9a..72dfa3d 100644
--- a/modules/nixos/sourceos-shell/default.nix
+++ b/modules/nixos/sourceos-shell/default.nix
@@ -35,6 +35,20 @@ in
       default = 7073;
       description = "Local port for the sourceos-shell derive/docd service.";
     };
+
+    searchProvider = {
+      mode = lib.mkOption {
+        type = lib.types.enum [ "linux-native" "launcher-bridge" "shell-native" ];
+        default = "launcher-bridge";
+        description = "Search routing mode during shell rollout.";
+      };
+
+      linuxFileProvider = lib.mkOption {
+        type = lib.types.enum [ "tracker3" "fd" "locate" ];
+        default = "tracker3";
+        description = "Linux-native file search provider used when scope=files.";
+      };
+    };
   };
 
   config = lib.mkIf cfg.enable {
@@ -45,11 +59,32 @@ in
       routerPort=${toString cfg.routerPort}
       pdfSecurePort=${toString cfg.pdfSecurePort}
       docdPort=${toString cfg.docdPort}
+      searchProvider.mode=${cfg.searchProvider.mode}
+      searchProvider.linuxFileProvider=${cfg.searchProvider.linuxFileProvider}
     '';
 
+    environment.etc."sourceos-shell/search-provider.json".text = builtins.toJSON {
+      mode = cfg.searchProvider.mode;
+      linuxFileProvider = cfg.searchProvider.linuxFileProvider;
+      invariant = "no_redundant_file_search";
+      scopes = {
+        apps = "launcher";
+        files = "linux-native-only";
+        web = "browser-agent";
+      };
+    };
+
+    systemd.targets.sourceos-shell = {
+      description = "SourceOS shell service graph";
+      wants = [ "sourceos-shell.service" "sourceos-router.service" "sourceos-pdf-secure.service" "sourceos-docd.service" ];
+      after = [ "network-online.target" ];
+      wantedBy = [ "multi-user.target" ];
+    };
+
     systemd.services.sourceos-shell = {
       description = "SourceOS shell runtime scaffold";
       wantedBy = [ "multi-user.target" ];
+      partOf = [ "sourceos-shell.target" ];
       serviceConfig = {
         Type = "simple";
         ExecStart = "${pkgs.coreutils}/bin/echo sourceos-shell runtime placeholder root=${cfg.packageRoot} port=${toString cfg.shellPort}";
@@ -59,6 +94,7 @@ in
     systemd.services.sourceos-router = {
       description = "SourceOS shell router scaffold";
       wantedBy = [ "multi-user.target" ];
+      partOf = [ "sourceos-shell.target" ];
       serviceConfig = {
         Type = "simple";
         ExecStart = "${pkgs.coreutils}/bin/echo sourceos-router placeholder port=${toString cfg.routerPort}";
@@ -68,10 +104,21 @@ in
     systemd.services.sourceos-pdf-secure = {
       description = "SourceOS shell pdf-secure scaffold";
       wantedBy = [ "multi-user.target" ];
+      partOf = [ "sourceos-shell.target" ];
       serviceConfig = {
         Type = "simple";
         ExecStart = "${pkgs.coreutils}/bin/echo sourceos-pdf-secure placeholder port=${toString cfg.pdfSecurePort}";
       };
     };
+
+    systemd.services.sourceos-docd = {
+      description = "SourceOS shell docd scaffold";
+      wantedBy = [ "multi-user.target" ];
+      partOf = [ "sourceos-shell.target" ];
+      serviceConfig = {
+        Type = "simple";
+        ExecStart = "${pkgs.coreutils}/bin/echo sourceos-docd placeholder port=${toString cfg.docdPort}";
+      };
+    };
   };
 }
diff --git a/profiles/linux-dev/default.nix b/profiles/linux-dev/default.nix
index f2ef598..678d171 100644
--- a/profiles/linux-dev/default.nix
+++ b/profiles/linux-dev/default.nix
@@ -2,6 +2,7 @@
 {
   imports = [
     ../../modules/build/default.nix
+    ../../profiles/linux-dev/sourceos-shell.nix
   ];
 
   sourceos.build = {
diff --git a/tests/sourceos-shell-module-contract.nix b/tests/sourceos-shell-module-contract.nix
new file mode 100644
index 0000000..dc8b6c6
--- /dev/null
+++ b/tests/sourceos-shell-module-contract.nix
@@ -0,0 +1,24 @@
+{ pkgs ? import <nixpkgs> {} }:
+pkgs.runCommand "sourceos-shell-module-contract" {
+  nativeBuildInputs = [ pkgs.gnugrep ];
+} ''
+  test -f ${../modules/nixos/sourceos-shell/default.nix}
+  test -f ${../profiles/linux-dev/sourceos-shell.nix}
+  test -f ${../linux/desktop/sourceos-shell.desktop}
+  test -f ${../linux/desktop/sourceos-search-provider.conf}
+  test -f ${../linux/systemd/sourceos-shell.service}
+  test -f ${../linux/systemd/sourceos-router.service}
+  test -f ${../linux/systemd/sourceos-pdf-secure.service}
+  test -f ${../linux/systemd/sourceos-docd.service}
+  test -f ${../linux/systemd/sourceos-shell.target}
+  grep -q '../../modules/nixos/sourceos-shell/default.nix' ${../profiles/linux-dev/sourceos-shell.nix}
+  grep -q 'sourceos.shell' ${../modules/nixos/sourceos-shell/default.nix}
+  grep -q 'sourceos-docd' ${../modules/nixos/sourceos-shell/default.nix}
+  grep -q 'searchProvider' ${../modules/nixos/sourceos-shell/default.nix}
+  grep -q 'systemd.targets.sourceos-shell' ${../modules/nixos/sourceos-shell/default.nix}
+  grep -q 'partOf = \[ "sourceos-shell.target" \]' ${../modules/nixos/sourceos-shell/default.nix}
+  grep -q 'no_redundant_file_search' ${../linux/desktop/sourceos-search-provider.conf}
+  grep -q 'sourceos-shell.service sourceos-router.service sourceos-pdf-secure.service sourceos-docd.service' ${../linux/systemd/sourceos-shell.target}
+  mkdir -p $out
+  echo validated > $out/result.txt
+''
diff --git a/tests/sourceos-shell-service-graph-contract.nix b/tests/sourceos-shell-service-graph-contract.nix
new file mode 100644
index 0000000..adac31a
--- /dev/null
+++ b/tests/sourceos-shell-service-graph-contract.nix
@@ -0,0 +1,12 @@
+{ pkgs ? import <nixpkgs> {} }:
+pkgs.runCommand "sourceos-shell-service-graph-contract" {
+  nativeBuildInputs = [ pkgs.gnugrep ];
+} ''
+  test -f ${../linux/systemd/sourceos-shell.target}
+  grep -q 'sourceos-shell.service sourceos-router.service sourceos-pdf-secure.service sourceos-docd.service' ${../linux/systemd/sourceos-shell.target}
+  grep -q 'systemd.targets.sourceos-shell' ${../modules/nixos/sourceos-shell/default.nix}
+  grep -q 'partOf = \[ "sourceos-shell.target" \]' ${../modules/nixos/sourceos-shell/default.nix}
+  grep -q 'sourceos-shell.target' ${../docs/sourceos-shell-service-graph.md}
+  mkdir -p $out
+  echo validated > $out/result.txt
+''