diff --git a/.claude-plugin/plugin.json b/.claude-plugin/plugin.json
index 166b256..57d02aa 100644
--- a/.claude-plugin/plugin.json
+++ b/.claude-plugin/plugin.json
@@ -1,6 +1,6 @@
 {
 	"name": "fleet-integration",
-	"version": "1.3.0",
+	"version": "1.4.0",
 	"description": "Integration playbooks for the oleks fleet, distilled from the 2026-07-21 k3s-over-ZeroTier connectivity research (27 incidents, 9 recurring patterns — catalogued on the oleks/cluster wiki page K3s-over-ZeroTier-Connectivity). Core finding: the failures were integration-shaped, not platform-shaped — undeclared state, half-finished migrations, hardcoded environment assumptions, half-implemented lifecycles, watchdog amplification. Six skills cover the levels of the system: integration-preflight (declared-vs-live drift audit before building on top), onboard-host (join a host to the fleet network + k3s), integrate-service (service end-to-end: chart, Flux, ingress, DNS, secrets, DB, TLS, deploy tracking), ephemeral-lifecycle (scale-to-zero credential/member lifecycle rules), add-watchdog (health-check design that doesn't amplify failures), finish-migration (cutover discipline: done means old state REMOVED and declared==live). Playbooks encode failure classes, not current facts — they direct verification against live sources of truth (fleet-modules/cluster-topology.nix, the wiki) rather than restating values that rot.",
 	"author": {
 		"name": "oleks",
diff --git a/bin/hooks b/bin/hooks
index 815156e..0594196 100755
Binary files a/bin/hooks and b/bin/hooks differ
diff --git a/failopen.go b/failopen.go
new file mode 100644
index 0000000..54f2697
--- /dev/null
+++ b/failopen.go
@@ -0,0 +1,62 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"sort"
+	"strings"
+)
+
+// unknownEntryPoint is the stable stderr marker this binary prints when it is
+// asked for a hook name it does not have. Tooling greps for it; humans read
+// the rest of the line.
+//
+// It exists because this path can NOT signal through the exit status. Claude
+// Code reads exit 2 from a PreToolUse hook as "block this tool call", so the
+// previous os.Exit(2) on an unknown name meant a hooks.json naming a hook the
+// compiled binary lacks took out the matched tool — for a Bash matcher, every
+// shell command, in EVERY concurrently running session on the host, not just
+// the one doing the rebuild.
+//
+// That skew is routine rather than exotic: this plugin ships a committed
+// prebuilt bin/hooks that CI does not rebuild, and oleks-local is a directory
+// source, so a live session sees an edited hooks.json the instant it is
+// written, against whatever binary is on disk.
+//
+// A missing notice is a far smaller loss than a missing tool, so this fails
+// open. Third independent occurrence of the same defect fleet-wide; see
+// oleks/claude-plugin-anxious#182 and kotkan/claude-plugin-decision-flow#85.
+const unknownEntryPoint = "fleet-integration/hooks: unknown-entry-point:"
+
+// registeredNames returns every entry point this binary actually has, sorted.
+func registeredNames() []string {
+	names := make([]string, 0, len(dispatch))
+	for k := range dispatch {
+		names = append(names, k)
+	}
+	sort.Strings(names)
+	return names
+}
+
+// failOpenUnknown reports an unusable invocation on stderr and returns, so the
+// caller can exit 0. stderr is the right channel: the harness surfaces it as a
+// diagnostic without blocking, which is exactly the "loud but harmless"
+// channel this case wants.
+func failOpenUnknown(name string) {
+	fmt.Fprintf(os.Stderr, "%s %q\n", unknownEntryPoint, name)
+	fmt.Fprintf(os.Stderr, "  registered: %s\n", strings.Join(registeredNames(), " "))
+	fmt.Fprintln(os.Stderr, "  allowing the call — a hooks.json/binary skew must not block a tool.")
+}
+
+// listEntryPoints handles the `list` subcommand, which prints the registered
+// entry points one per line. It replaces reading a skew off a non-zero exit
+// status, which is no longer available now that an unknown name fails open.
+func listEntryPoints() bool {
+	if len(os.Args) == 2 && os.Args[1] == "list" {
+		for _, n := range registeredNames() {
+			fmt.Println(n)
+		}
+		return true
+	}
+	return false
+}
diff --git a/failopen_test.go b/failopen_test.go
new file mode 100644
index 0000000..c3202ad
--- /dev/null
+++ b/failopen_test.go
@@ -0,0 +1,93 @@
+package main
+
+import (
+	"errors"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// buildHooks compiles this package into a temp binary. These tests assert on
+// the PROCESS EXIT STATUS, which is the whole property at issue and which a
+// function-level test cannot observe.
+func buildHooks(t *testing.T) string {
+	t.Helper()
+	bin := filepath.Join(t.TempDir(), "hooks")
+	if out, err := exec.Command("go", "build", "-o", bin, ".").CombinedOutput(); err != nil {
+		t.Fatalf("building test binary: %v\n%s", err, out)
+	}
+	return bin
+}
+
+func runHooks(t *testing.T, bin string, args ...string) (stdout, stderr string, code int) {
+	t.Helper()
+	cmd := exec.Command(bin, args...)
+	cmd.Stdin = strings.NewReader("{}")
+	var so, se strings.Builder
+	cmd.Stdout, cmd.Stderr = &so, &se
+	if err := cmd.Run(); err != nil {
+		var ee *exec.ExitError
+		if !errors.As(err, &ee) {
+			t.Fatalf("running %s: %v", bin, err)
+		}
+		code = ee.ExitCode()
+	}
+	return so.String(), se.String(), code
+}
+
+// An unknown entry point must NOT exit non-zero. Claude Code reads exit 2 from
+// a PreToolUse hook as "block this tool call", so a hooks.json naming a hook
+// this binary lacks would take out the matched tool in every running session
+// on the host — see the note on unknownEntryPoint.
+func TestUnknownEntryPointFailsOpen(t *testing.T) {
+	_, stderr, code := runHooks(t, buildHooks(t), "definitely-not-a-registered-hook")
+	if code != 0 {
+		t.Errorf("exit = %d, want 0 (a hooks.json/binary skew must not block a tool)", code)
+	}
+	if !strings.Contains(stderr, unknownEntryPoint) {
+		t.Errorf("stderr missing %q marker, got: %s", unknownEntryPoint, stderr)
+	}
+	if !strings.Contains(stderr, "registered:") {
+		t.Errorf("stderr should name the registered entry points, got: %s", stderr)
+	}
+}
+
+// A missing entry point is the same fault as an unknown one.
+func TestMissingEntryPointFailsOpen(t *testing.T) {
+	_, stderr, code := runHooks(t, buildHooks(t))
+	if code != 0 {
+		t.Errorf("exit = %d, want 0", code)
+	}
+	if !strings.Contains(stderr, unknownEntryPoint) {
+		t.Errorf("stderr missing %q marker, got: %s", unknownEntryPoint, stderr)
+	}
+}
+
+// `list` is how tooling detects a skew now that it cannot read one off a
+// non-zero exit status.
+func TestListPrintsEveryRegisteredEntryPoint(t *testing.T) {
+	stdout, _, code := runHooks(t, buildHooks(t), "list")
+	if code != 0 {
+		t.Fatalf("exit = %d, want 0", code)
+	}
+	got := map[string]bool{}
+	for _, line := range strings.Fields(stdout) {
+		got[line] = true
+	}
+	for name := range dispatch {
+		if !got[name] {
+			t.Errorf("list omitted registered entry point %q (got %q)", name, stdout)
+		}
+	}
+	if len(got) != len(dispatch) {
+		t.Errorf("list printed %d names, want %d", len(got), len(dispatch))
+	}
+}
+
+// `list` must not shadow a real hook.
+func TestListIsNotARegisteredHookName(t *testing.T) {
+	if _, clash := dispatch["list"]; clash {
+		t.Fatal(`a hook is registered as "list", which the list subcommand shadows`)
+	}
+}
diff --git a/main.go b/main.go
index d68a9f0..8797cdc 100644
--- a/main.go
+++ b/main.go
@@ -32,14 +32,18 @@ var dispatch = map[string]handler{
 }
 
 func main() {
+	if listEntryPoints() {
+		return
+	}
+
 	if len(os.Args) < 2 {
-		fmt.Fprintln(os.Stderr, "usage: hooks <hook-name>")
-		os.Exit(2)
+		failOpenUnknown("")
+		return
 	}
 	h, ok := dispatch[os.Args[1]]
 	if !ok {
-		fmt.Fprintf(os.Stderr, "hooks: unknown hook %q\n", os.Args[1])
-		os.Exit(2)
+		failOpenUnknown(os.Args[1])
+		return
 	}
 	raw, err := io.ReadAll(os.Stdin)
 	if err != nil {