diff --git a/packages/agent-memory-sync/docs/machine-setup.md b/packages/agent-memory-sync/docs/machine-setup.md
index a3970b5..3947814 100644
--- a/packages/agent-memory-sync/docs/machine-setup.md
+++ b/packages/agent-memory-sync/docs/machine-setup.md
@@ -77,7 +77,8 @@ This document wires together the pieces already documented individually
   must be running on every fallback machine.
 
 Machine-specific values (paths, SSH alias) are committed as profile files
-under `profiles/`: `profiles/macbook.json`, `profiles/mac-mini.json`, and a
+under `profiles/`: `profiles/macbook.json`, `profiles/mac-mini.json`,
+`profiles/linux.json` (the Linux desktop set up via (c) below), and a
 template for further machines, `profiles/linux.example.json`. Each profile
 file documents its own placeholders and the namespace-divergence gotcha
 in its `"//"` field — read the profile you're activating before copying
@@ -331,7 +332,8 @@ bullet at the top of this document.
 
 ## e) machine-state payload (toolchain snapshots)
 
-Every committed profile (`profiles/mac-mini.json`, `profiles/macbook.json`)
+Every committed machine profile (`profiles/mac-mini.json`,
+`profiles/macbook.json`, `profiles/linux.json`)
 carries a **second, independent** `syncPaths` entry alongside the `memory`
 one described at the top of this document:
 
@@ -399,11 +401,11 @@ exist ahead of any sync.
 ## f) frictions payload (friction-log exports)
 
 Every committed profile (`profiles/mac-mini.json`, `profiles/macbook.json`,
-`profiles/linux.example.json`) also carries an **independent** `syncPaths`
-entry pointing at `~/.harness/frictions` — the third entry in
-`mac-mini.json`/`macbook.json` (after `memory` and `machine-state`), and
-the second in `linux.example.json` (that template does not yet include a
-`machine-state` entry):
+`profiles/linux.json`, `profiles/linux.example.json`) also carries an
+**independent** `syncPaths` entry pointing at `~/.harness/frictions` — the
+third entry in `mac-mini.json`/`macbook.json`/`linux.json` (after `memory`
+and `machine-state`), and the second in `linux.example.json` (that template
+does not yet include a `machine-state` entry):
 
 ```json
 { "source": "/Users/<user>/.harness/frictions", "destination": "frictions", "kind": "directory" }
diff --git a/packages/agent-memory-sync/profiles/linux.json b/packages/agent-memory-sync/profiles/linux.json
new file mode 100644
index 0000000..274f6a8
--- /dev/null
+++ b/packages/agent-memory-sync/profiles/linux.json
@@ -0,0 +1,51 @@
+{
+  "//": [
+    "Machine profile: Linux desktop (WSL2, DESKTOP-9TDLGAR) — fallback",
+    "machine. The Mac mini is the single source of truth (see mac-mini.json);",
+    "this machine pulls via the periodic sync timer and pushes debounced",
+    "snapshots via `watch`. Filled in from linux.example.json — read that",
+    "template's '//' field for the full rationale; the load-bearing invariants",
+    "restated inline: the memory entry's destination must be the literal",
+    "'memory', never '.' (a '.' destination is silently unmappable on",
+    "pull/restore); stateDir must stay OUTSIDE rootDir (the '.' walk would",
+    "otherwise sync the tool's own state); rootDir/stateDir are absolute,",
+    "the loader performs no tilde expansion. reachabilityTimeoutMs is 10000",
+    "like macbook.json (ssh-reached spoke), not the template's 5000.",
+    "",
+    "repositorySubdir MUST stay the fixed literal 'pandora', identical on",
+    "every machine sharing the remote — a per-machine value silently",
+    "partitions the bare repo into disjoint trees (happened before, caught by",
+    "a live cross-machine E2E test). See the template / machine-setup.md.",
+    "",
+    "rootDir is this machine's own Claude Code slug, read off",
+    "`ls ~/.claude/projects/` HERE (encodes OS user 'lan' + checkout path",
+    "/home/lan/git/pandora) — never copied from another machine's profile.",
+    "",
+    "Deviation from linux.example.json, deliberate: a third syncPaths entry",
+    "for machine-state (absolute source ~/.harness/machine-state), which the",
+    "template does not yet carry (noted in machine-setup.md section f) —",
+    "without it this machine is invisible to the toolchain-parity check.",
+    "Producer: `harness session-start toolchain-parity`; convention is",
+    "owner-writes-only, one file per machine (machine-state/linux.json).",
+    "",
+    "frictions producer: friction-log sync_export in",
+    "~/.config/friction-log/config.yml writes ~/.harness/frictions/linux.json.",
+    "",
+    "Activation: pass BOTH --config (this file) and the profile name",
+    "positionally:",
+    "  agent-memory-sync run linux --config profiles/linux.json"
+  ],
+  "profile": "linux",
+  "rootDir": "/home/lan/.claude/projects/-home-lan-git-pandora/memory",
+  "remoteUrl": "mini:~/memory-sync/pandora-memory.git",
+  "branch": "main",
+  "repositorySubdir": "pandora",
+  "stateDir": "/home/lan/.agent-memory-sync/linux",
+  "conflictStrategy": "inline-markers",
+  "reachabilityTimeoutMs": 10000,
+  "syncPaths": [
+    { "source": ".", "destination": "memory", "kind": "directory" },
+    { "source": "/home/lan/.harness/machine-state", "destination": "machine-state", "kind": "directory" },
+    { "source": "/home/lan/.harness/frictions", "destination": "frictions", "kind": "directory" }
+  ]
+}
diff --git a/packages/agent-memory-sync/tests/integration/cross-machine-profiles.test.ts b/packages/agent-memory-sync/tests/integration/cross-machine-profiles.test.ts
index c06bfc9..a725393 100644
--- a/packages/agent-memory-sync/tests/integration/cross-machine-profiles.test.ts
+++ b/packages/agent-memory-sync/tests/integration/cross-machine-profiles.test.ts
@@ -126,16 +126,16 @@ test("macbook and mac-mini profiles share one remote tree and see each other's p
   );
 });
 
-test("profiles/macbook.json, profiles/mac-mini.json, and profiles/linux.example.json all declare the same repositorySubdir", () => {
+test("all committed profiles (macbook, mac-mini, linux, linux.example) declare the same repositorySubdir", () => {
   // A narrower, faster companion to the end-to-end test above: pins the
   // specific config field that caused the divergence directly against the
   // committed files, independent of any CLI/git plumbing. Includes
   // linux.example.json — the copy-paste source for any new machine — so a
   // future template edit that reintroduces a per-machine placeholder (as
   // this template originally had, mirroring the pre-fix macbook/mac-mini
-  // profiles) is caught here too, not just on the two profiles already in
+  // profiles) is caught here too, not just on the profiles already in
   // active use.
-  const profileFiles = ["macbook.json", "mac-mini.json", "linux.example.json"];
+  const profileFiles = ["macbook.json", "mac-mini.json", "linux.json", "linux.example.json"];
   const settingsByFile = Object.fromEntries(
     profileFiles.map((file) => [file, JSON.parse(readText(path.join(PROFILES_DIR, file)))])
   );
@@ -196,9 +196,10 @@ test("profiles/macbook.json, profiles/mac-mini.json, and profiles/linux.example.
   }
 
   // Same pin for the pre-existing machine-state entry, closing the identical
-  // #64 coverage gap — macbook.json and mac-mini.json only, since
-  // linux.example.json's template has never carried a machine-state entry.
-  for (const file of ["macbook.json", "mac-mini.json"]) {
+  // #64 coverage gap — every committed machine profile, but not
+  // linux.example.json, since the template has never carried a machine-state
+  // entry (linux.json adds it deliberately; see machine-setup.md section f).
+  for (const file of ["macbook.json", "mac-mini.json", "linux.json"]) {
     const machineStateEntries = findEntriesByDestination(settingsByFile[file].syncPaths, "machine-state");
     assert.equal(
       machineStateEntries.length,