diff --git a/ansible/infra/403_service_probe_registration.yml b/ansible/infra/403_service_probe_registration.yml
index b716faa..a46682a 100644
--- a/ansible/infra/403_service_probe_registration.yml
+++ b/ansible/infra/403_service_probe_registration.yml
@@ -37,7 +37,13 @@
 
   vars:
     probes:
-      - {name: bitcoin-knots,    host: knots_box_local}
+      # failure_threshold 4: this probe runs every MINUTE, and bitcoind turns RPC
+      # away for 1-3 minutes when a block lands - validation on the saturated
+      # HDD plus Fulcrum/mempool/DATUM all fetching the block at once (93
+      # "work queue depth exceeded" in one day, 2026-10-18). At 1, every slow
+      # block paged. 4 consecutive failed minutes is past any block burst seen,
+      # and a real outage still alerts within ~5 minutes.
+      - {name: bitcoin-knots,    host: knots_box_local, failure_threshold: 4}
       - {name: datum-gateway,    host: knots_box_local}
       - {name: fulcrum,          host: fulcrum_box_local}
       - {name: phoenixd,         host: vipy}
@@ -54,6 +60,16 @@
       - {name: navidrome,        host: music_box_local}
       - {name: jar-lid-archive-staging, host: jar_lid_staging_local}
 
+    # The alert every probe gets. failure-threshold is 1 - the heartbeat window
+    # is the tolerance, see the note above - unless a probe sets
+    # failure_threshold, for checks that legitimately fail for a minute or two.
+    probe_alert:
+      type: signal
+      failure-threshold: 1
+      success-threshold: 2
+      send-on-resolved: true
+      minimum-reminder-interval: 6h
+
   tasks:
     - name: Build the probe endpoint list
       ansible.builtin.set_fact:
@@ -61,19 +77,13 @@
           'name': item.name,
           'group': 'probe',
           'token': gatus_push_tokens[item.host],
-          'heartbeat': item.heartbeat | default('11m')}] }}"
+          'heartbeat': item.heartbeat | default('11m'),
+          'alerts': [probe_alert | combine({'failure-threshold': item.failure_threshold | default(1)})]}] }}"
       loop: "{{ probes }}"
 
     - name: Register the probe endpoints
       ansible.builtin.include_role:
         name: gatus_endpoint
       vars:
-        gatus_endpoint_default_alerts:
-          - type: signal
-            # 1, not 3: the heartbeat window is the tolerance. See the note above.
-            failure-threshold: 1
-            success-threshold: 2
-            send-on-resolved: true
-            minimum-reminder-interval: 6h
         gatus_endpoint_name: probes
         gatus_endpoint_external: "{{ probe_endpoints }}"
diff --git a/ansible/roles/bitcoin_knots/defaults/main.yml b/ansible/roles/bitcoin_knots/defaults/main.yml
index 1045e77..01a352d 100644
--- a/ansible/roles/bitcoin_knots/defaults/main.yml
+++ b/ansible/roles/bitcoin_knots/defaults/main.yml
@@ -22,6 +22,15 @@ bitcoin_rpc_port: 8332
 bitcoin_p2p_port: 8333
 bitcoin_rpc_bind: "0.0.0.0"
 
+# RPC capacity. When a block lands, Fulcrum, mempool and DATUM all fetch it at
+# once while validation holds the node busy on a saturated HDD; with the
+# defaults the queue overflowed and bitcoind REJECTED calls ("http work queue
+# depth exceeded" - 93 times on 2026-10-18), which also made the health probe
+# flap. A deeper queue lets those bursts wait instead of failing. Costs a few
+# idle threads and a little memory.
+bitcoin_rpcworkqueue: 64
+bitcoin_rpcthreads: 8
+
 # Build options
 bitcoin_build_jobs: 4  # Parallel build jobs (-j flag), adjust based on CPU cores
 bitcoin_build_prefix: /usr/local
diff --git a/ansible/roles/bitcoin_knots/templates/bitcoin.conf.j2 b/ansible/roles/bitcoin_knots/templates/bitcoin.conf.j2
index 5277a3c..4187e24 100644
--- a/ansible/roles/bitcoin_knots/templates/bitcoin.conf.j2
+++ b/ansible/roles/bitcoin_knots/templates/bitcoin.conf.j2
@@ -11,6 +11,8 @@ rpcpassword={{ bitcoin_rpc_password }}
 rpcbind={{ bitcoin_rpc_bind }}
 rpcport={{ bitcoin_rpc_port }}
 rpcallowip=0.0.0.0/0
+rpcworkqueue={{ bitcoin_rpcworkqueue }}
+rpcthreads={{ bitcoin_rpcthreads }}
 
 # Network Configuration
 listen=1