diff --git a/fleetd/src/main/java/dev/ltms/fleet/rest/FleetApp.java b/fleetd/src/main/java/dev/ltms/fleet/rest/FleetApp.java
index 2541660..2ebf041 100644
--- a/fleetd/src/main/java/dev/ltms/fleet/rest/FleetApp.java
+++ b/fleetd/src/main/java/dev/ltms/fleet/rest/FleetApp.java
@@ -510,6 +510,12 @@ public final class FleetApp {
             ctx.status(400).json(Map.of("error", "unknown_profile", "detail", e.getMessage()));
         } catch (PeerUnreachableException e) {
             ctx.status(502).json(Map.of("error", "spawn_timeout", "detail", e.getMessage()));
+        } catch (HerdrException e) {
+            // fleetd #304: not every herdr failure on the spawn path is a readiness timeout, so
+            // PeerUnreachableException above does not cover this. Without this catch the exception
+            // escapes to Javalin's default 500, while fleet_spawn reports the same failure as a
+            // clean named error (FleetMcp.spawn) — the #297 one-door-guarded shape.
+            herdrError(ctx, e);
         }
     }
 
@@ -530,13 +536,29 @@ public final class FleetApp {
         return (s == null || s.isBlank()) ? null : s;
     }
 
-    /** Tear a worker down by pane id. */
+    /**
+     * Tear a worker down by pane id.
+     *
+     * <p>fleetd #304: the {@code HerdrException} catch is not cosmetic. {@code release} deregisters
+     * the session, notifies the release listener and preserves a dirty worktree <em>before</em> it
+     * calls {@code launcher.stop}, so a throw from that stop arrives after the teardown the caller
+     * asked for has already happened. Letting it escape gave Javalin's default 500, which tells the
+     * caller to retry — and the retry finds nothing in the registry, reaches the same stop, and
+     * throws again, so it can never succeed. {@code herdrError} instead answers 404 ("the pane is
+     * gone, stop retrying") or 502 ("herdr is upstream and broken, a retry may help"), matching what
+     * {@code fleet_stop} reports for the same failure.
+     */
     private void stopMember(Context ctx) {
         String paneId = ctx.pathParam("paneId");
         if (!allow(ctx, routeAction("DELETE /members/{paneId}"), paneId)) {
             return;
         }
-        sessions.release(paneId);
+        try {
+            sessions.release(paneId);
+        } catch (HerdrException e) {
+            herdrError(ctx, e);
+            return;
+        }
         ctx.status(204);
     }
 
diff --git a/fleetd/src/test/java/dev/ltms/fleet/rest/FleetAppTest.java b/fleetd/src/test/java/dev/ltms/fleet/rest/FleetAppTest.java
index a3e7a67..be273a1 100644
--- a/fleetd/src/test/java/dev/ltms/fleet/rest/FleetAppTest.java
+++ b/fleetd/src/test/java/dev/ltms/fleet/rest/FleetAppTest.java
@@ -415,7 +415,11 @@ class FleetAppTest {
         FakeHerdr herdr = new FakeHerdr().agentNameTakenTimes(99);
         int port = start(herdr, "http://gx00.gw:8000", Set.of("gx00.gw"));
 
-        assertEquals(500, req(port, "POST", "/members").statusCode());
+        // fleetd #304: 502, not Javalin's default 500 — the herdr failure is named, and the body
+        // carries herdr's own message, matching what fleet_spawn reports for the same failure.
+        HttpResponse<String> res = req(port, "POST", "/members");
+        assertEquals(502, res.statusCode());
+        assertEquals("herdr_error", mapper.readTree(res.body()).get("error").asText());
         assertTrue(herdr.called("tab.create"), "a tab was created before the failed start");
         assertEquals("w9:t2", params(herdr, "tab.close").get("tab_id"), "orphaned tab must be closed");
     }
@@ -733,7 +737,12 @@ class FleetAppTest {
         int port = start(herdr, "http://gx00.gw:8000", Set.of("gx00.gw"));
 
         // A genuine teardown failure must surface, not be reported as a successful 204.
-        assertEquals(500, req(port, "DELETE", "/members/w9:pW").statusCode());
+        // fleetd #304: it surfaces as a named 502 rather than Javalin's default 500. The property
+        // this test guards is "not 204" and the herdr detail reaching the caller — a bare 500 gave
+        // the body "Server Error" and said nothing about herdr.
+        HttpResponse<String> res = req(port, "DELETE", "/members/w9:pW");
+        assertEquals(502, res.statusCode());
+        assertEquals("herdr_error", mapper.readTree(res.body()).get("error").asText());
         assertFalse(herdr.called("tab.close"), "tab is not removed when the pane close failed");
     }
 
@@ -746,4 +755,5 @@ class FleetAppTest {
         assertEquals(204, req(port, "DELETE", "/members/w9:pW").statusCode());
         assertTrue(herdr.called("tab.close"));
     }
+
 }