diff --git a/TODO.md b/TODO.md
index ea100690..23538422 100644
--- a/TODO.md
+++ b/TODO.md
@@ -306,6 +306,28 @@ everything still open, in the order it should be tackled.
             loops so it can be tested without them. The second is the real
             work.
             (Recorded 2026-08-20.)
+      - [ ] **THE SESSION AGENT DOES NOT RUN ON WINDOWS.** Found 2026-08-20,
+            the first time the JavaScript suite executed there: four test
+            files die in `beforeAll` with
+            `listen EACCES ... \agent.sock`. Node on Windows requires a named
+            pipe (`\\.\pipe\name`) for `server.listen(path)`; a filesystem
+            path is not a valid endpoint. Nothing about the daemon works
+            there — no `seedpass agent`, so no held seeds, no tokens, no
+            high-risk sessions, no sink delivery.
+
+            This is not a path substitution. The agent's ACCESS CONTROL is the
+            socket's 0600 mode: the trust boundary is "only this user can
+            connect", enforced by the filesystem. Named pipes have their own
+            ACL model, so supporting Windows means answering what the 0600
+            was buying and how to buy it again — a security design question,
+            and it should be decided rather than improvised.
+
+            Until then the four files are excluded on Windows in
+            js/packages/cli/vitest.config.ts, with the reason written there.
+            With TypeScript becoming the only implementation this is a
+            shipping decision: either the agent gains a Windows transport, or
+            SeedPass documents the daemon as POSIX-only and the Windows CLI
+            works without it.
       - [ ] **Are vault files protected from other users on Windows?**
             SCOPE GREW 2026-08-20: this is no longer two Python tests. When
             the JavaScript suite first ran on Windows, eight more `0600`
diff --git a/js/packages/cli/vitest.config.ts b/js/packages/cli/vitest.config.ts
index 1b5a892b..db80e7e4 100644
--- a/js/packages/cli/vitest.config.ts
+++ b/js/packages/cli/vitest.config.ts
@@ -1,4 +1,27 @@
 import { defineConfig } from "vitest/config";
+import process from "node:process";
+
+/**
+ * The agent's transport is a Unix domain socket at a filesystem path, and its
+ * access control IS the socket's 0600 mode. Node on Windows wants a named
+ * pipe (`\\\\.\\pipe\\name`) for `server.listen(path)`, so a path like
+ * `C:\...\agent.sock` fails with EACCES before a single assertion runs —
+ * these four files die in beforeAll.
+ *
+ * Excluded here rather than skipped test by test, because the reason is one
+ * fact about the platform and not a property of any individual test: the
+ * session daemon does not run on Windows today. That is a real gap in a
+ * product about to ship TypeScript as its only implementation, and it is
+ * recorded in TODO.md — supporting it needs a named-pipe transport AND a
+ * Windows answer to what 0600 on the socket was buying, which is a security
+ * design question rather than a path substitution.
+ */
+const AGENT_TESTS = [
+  "test/agentSecurity.test.ts",
+  "test/tokens.test.ts",
+  "test/highRisk.test.ts",
+  "test/profiles.test.ts",
+];
 
 export default defineConfig({
   test: {
@@ -7,5 +30,6 @@ export default defineConfig({
     // comfortably exceeds the 5s default once several files run in parallel.
     testTimeout: 60_000,
     hookTimeout: 60_000,
+    ...(process.platform === "win32" ? { exclude: ["**/node_modules/**", ...AGENT_TESTS] } : {}),
   },
 });