diff --git a/crates/cli/src/adapters/hermes.rs b/crates/cli/src/adapters/hermes.rs
index 23acbad8..815b5234 100644
--- a/crates/cli/src/adapters/hermes.rs
+++ b/crates/cli/src/adapters/hermes.rs
@@ -48,6 +48,12 @@ pub(crate) fn adapt(payload: Value, headers: &HeaderMap) -> AdapterOutcome {
             response: json!({}),
         };
     }
+    if normalized == "pretoolcall" && !hermes_pre_tool_call_is_correlatable(&payload, headers) {
+        return AdapterOutcome {
+            events: Vec::new(),
+            response: json!({}),
+        };
+    }
 
     // `on_session_end` is a Hermes per-turn boundary, not user-visible trajectory content.
     // Emitting it as both HookMark and TurnEnded polluted ATIF with system rows whose only purpose
@@ -221,6 +227,42 @@ fn hermes_payload_exact(payload: &Value, event_name: &str) -> bool {
     }
 }
 
+fn hermes_pre_tool_call_is_correlatable(payload: &Value, headers: &HeaderMap) -> bool {
+    // Public Hermes releases can emit `pre_tool_call` with only a turn/task id. Treating that
+    // `task_id` as a session opens a synthetic session that is later closed as `gateway_shutdown`.
+    // Keep pre-tool spans only when they can be routed to a real session and paired with a stable
+    // tool call id. The matching `post_tool_call` still records the tool result.
+    has_explicit_hermes_session_id(payload, headers) && has_explicit_hermes_tool_call_id(payload)
+}
+
+fn has_explicit_hermes_session_id(payload: &Value, headers: &HeaderMap) -> bool {
+    header_has_value(headers, "x-nemo-relay-session-id")
+        || header_has_value(headers, "x-claude-code-session-id")
+        || hermes_string_at(payload, "session_id").is_some()
+        || hermes_string_at(payload, "sessionId").is_some()
+        || value_at(payload, &["session", "id"]).is_some()
+        || hermes_string_at(payload, "conversation_id").is_some()
+        || hermes_string_at(payload, "conversationId").is_some()
+        || hermes_string_at(payload, "parent_session_id").is_some()
+}
+
+fn has_explicit_hermes_tool_call_id(payload: &Value) -> bool {
+    hermes_string_at(payload, "tool_call_id").is_some()
+        || hermes_string_at(payload, "toolCallId").is_some()
+        || hermes_string_at(payload, "tool_use_id").is_some()
+        || hermes_string_at(payload, "call_id").is_some()
+        || value_at(payload, &["tool", "id"]).is_some()
+        || value_at(payload, &["tool_input", "id"]).is_some()
+        || hermes_string_at(payload, "id").is_some()
+}
+
+fn header_has_value(headers: &HeaderMap, name: &str) -> bool {
+    headers
+        .get(name)
+        .and_then(|value| value.to_str().ok())
+        .is_some_and(|value| !value.trim().is_empty())
+}
+
 fn hermes_exact_request(payload: &Value) -> Option<Value> {
     let request = hermes_value_at(payload, "request")?;
     // Hermes bounds hook payload size before invoking plugins. A truncated payload is intentionally
diff --git a/crates/cli/tests/coverage/adapters_tests.rs b/crates/cli/tests/coverage/adapters_tests.rs
index 9e21b4ed..e8bfb598 100644
--- a/crates/cli/tests/coverage/adapters_tests.rs
+++ b/crates/cli/tests/coverage/adapters_tests.rs
@@ -286,9 +286,9 @@ fn maps_hermes_shell_hook_tool_payload() {
             "hook_event_name": "pre_tool_call",
             "tool_name": "terminal",
             "tool_input": { "command": "pwd" },
-            "session_id": "",
+            "session_id": "hermes-session",
             "extra": {
-                "task_id": "hermes-session",
+                "task_id": "task-1",
                 "tool_call_id": "tool-1"
             }
         }),
@@ -308,6 +308,23 @@ fn maps_hermes_shell_hook_tool_payload() {
     assert_eq!(outcome.response, json!({}));
 }
 
+#[test]
+fn drops_uncorrelatable_hermes_pre_tool_call() {
+    let headers = HeaderMap::new();
+    let outcome = hermes::adapt(
+        json!({
+            "hook_event_name": "pre_tool_call",
+            "task_id": "task-1",
+            "tool_name": "terminal",
+            "tool_input": { "command": "pwd" }
+        }),
+        &headers,
+    );
+
+    assert!(outcome.events.is_empty());
+    assert_eq!(outcome.response, json!({}));
+}
+
 #[test]
 fn maps_hermes_subagent_child_identifiers() {
     let headers = HeaderMap::new();
diff --git a/crates/cli/tests/coverage/session_tests.rs b/crates/cli/tests/coverage/session_tests.rs
index d4a0be91..6a1f9be7 100644
--- a/crates/cli/tests/coverage/session_tests.rs
+++ b/crates/cli/tests/coverage/session_tests.rs
@@ -1451,6 +1451,53 @@ async fn writes_hermes_api_hook_usage_to_atif_metrics() {
     assert_eq!(atif["final_metrics"]["total_cached_tokens"], json!(3));
 }
 
+#[tokio::test]
+async fn hermes_uncorrelatable_pre_tool_call_does_not_create_shutdown_trajectory() {
+    let _guard = OBSERVABILITY_PLUGIN_TEST_LOCK.lock().await;
+    let temp = tempfile::tempdir().unwrap();
+    let atif_dir = temp.path().join("atif");
+    install_test_atif_plugin(&atif_dir).await;
+    let config = session_test_config();
+    let manager = SessionManager::new(config);
+    let headers = HeaderMap::new();
+
+    for payload in [
+        json!({
+            "hook_event_name": "on_session_start",
+            "session_id": "hermes-main"
+        }),
+        json!({
+            "hook_event_name": "pre_tool_call",
+            "task_id": "task-1",
+            "tool_name": "terminal",
+            "tool_input": { "command": "pwd" }
+        }),
+        json!({
+            "hook_event_name": "on_session_finalize",
+            "session_id": "hermes-main"
+        }),
+    ] {
+        let outcome = crate::adapters::hermes::adapt(payload, &headers);
+        manager
+            .apply_events(&headers, outcome.events)
+            .await
+            .unwrap();
+    }
+
+    manager.close_all("gateway_shutdown").await.unwrap();
+    clear_plugin_configuration().unwrap();
+
+    let trajectories: Vec<Value> = std::fs::read_dir(&atif_dir)
+        .unwrap()
+        .filter_map(Result::ok)
+        .map(|entry| serde_json::from_slice(&std::fs::read(entry.path()).unwrap()).unwrap())
+        .collect();
+    let serialized = serde_json::to_string(&trajectories).unwrap();
+    assert!(serialized.contains("hermes-main"));
+    assert!(!serialized.contains("task-1"));
+    assert!(!serialized.contains("gateway_shutdown"));
+}
+
 #[tokio::test]
 async fn hermes_turn_end_snapshots_atif_without_boundary_system_step() {
     let _guard = OBSERVABILITY_PLUGIN_TEST_LOCK.lock().await;