diff --git a/protocol/agent/v1/fixtures/heartbeat/MANIFEST.sha256 b/protocol/agent/v1/fixtures/heartbeat/MANIFEST.sha256
index fa096e9e7..9de2fce00 100644
--- a/protocol/agent/v1/fixtures/heartbeat/MANIFEST.sha256
+++ b/protocol/agent/v1/fixtures/heartbeat/MANIFEST.sha256
@@ -1,5 +1,6 @@
 975c1ca53eefeef6766a6fc0b3d3281f7408255342b0686e5e2aee5ad055414c  duplicate.json
 963529a38a02849c6c2acc6d72668dca9f63218b49c89fae41a451b584850411  overflow.json
+d8cf9de12c459aff83736d761ba003ca2544e45477fbbc5d1c6ae43a1e78a482  producer-capabilities.json
 e3adeee1c8a19aa17e70894896fb79c072e3785bea3611b93c11e79f039ed5af  stale.json
 22cc7337f545271ebf11ca6b76e7e479d62c51278ac001a8d870b07d0fa9884e  unknown.json
 b06a72ff1d964efe65e996797705ec2ef72574a813aec5d8e9aff26c899f1352  valid.json
diff --git a/protocol/agent/v1/fixtures/heartbeat/producer-capabilities.json b/protocol/agent/v1/fixtures/heartbeat/producer-capabilities.json
new file mode 100644
index 000000000..6b9c1033c
--- /dev/null
+++ b/protocol/agent/v1/fixtures/heartbeat/producer-capabilities.json
@@ -0,0 +1,52 @@
+{
+  "protocolVersion": "v1",
+  "fixtureSet": "heartbeat",
+  "fixture": "producer-capabilities",
+  "description": "The exact base and diagnostic capability tokens published by a RustFS agent heartbeat.",
+  "baseCapabilities": [
+    "heartbeat",
+    "diagnostics.policy.v1",
+    "inventory.environment@1"
+  ],
+  "producerCapabilities": [
+    "performance.client@1",
+    "performance.drive@1",
+    "performance.object@1",
+    "performance.siteReplication@1",
+    "logs.capture@1",
+    "profile.cpu@1",
+    "profile.memory@1",
+    "profile.threads@1",
+    "telemetry.record@1",
+    "telemetry.otlp@1",
+    "telemetry.replay@1",
+    "top.api@1",
+    "top.disk@1",
+    "top.locks@1",
+    "top.net@1",
+    "top.rpc@1",
+    "inspect.object@1"
+  ],
+  "heartbeatCapabilities": [
+    "heartbeat",
+    "diagnostics.policy.v1",
+    "inventory.environment@1",
+    "performance.client@1",
+    "performance.drive@1",
+    "performance.object@1",
+    "performance.siteReplication@1",
+    "logs.capture@1",
+    "profile.cpu@1",
+    "profile.memory@1",
+    "profile.threads@1",
+    "telemetry.record@1",
+    "telemetry.otlp@1",
+    "telemetry.replay@1",
+    "top.api@1",
+    "top.disk@1",
+    "top.locks@1",
+    "top.net@1",
+    "top.rpc@1",
+    "inspect.object@1"
+  ]
+}
diff --git a/protocol/agent/v1/fixtures/manifest.sha256 b/protocol/agent/v1/fixtures/manifest.sha256
index 152bdd0c8..cd0e69cb2 100644
--- a/protocol/agent/v1/fixtures/manifest.sha256
+++ b/protocol/agent/v1/fixtures/manifest.sha256
@@ -1,7 +1,7 @@
 a499742c06046e9cf2f781fc17d8b4cf95e018ab45fa41ee5944ba15b0e2902c  auth
 9b54e39584a442270ae486e8378df1d6f168c45d0c59baba9459b46bb212d2df  version
 159d116e965b51771f1687fc6ec9bdfbf2a4a0e6d6aa26d3f1046b3dac2697dd  registration
-f707b09b257c7d652eff2a3f680ecb0c8c45ebb4c2defa8dc07f9dd7ee46ca04  heartbeat
+5905ef6b39f02d5846912878c2762537e54875ef1a8666a2ee2be17b489e9f68  heartbeat
 cc6c3f3bf5e6a938f2e00b8ce42d8fa7bfb974f4eb2927101d4ede4ebdc10dd5  inventory
 0207458ec9b97b368e2f347da112511a3aabd27d752890cacda4fa2408e7f19e  object-performance
 a464d4c695d76dd985c0f2abf68c2135c080221098ad2427022f85243a7bf6ae  network-performance
diff --git a/rustfs/tests/agent_protocol_fixtures.rs b/rustfs/tests/agent_protocol_fixtures.rs
index 0cee61d08..882f1f204 100644
--- a/rustfs/tests/agent_protocol_fixtures.rs
+++ b/rustfs/tests/agent_protocol_fixtures.rs
@@ -24,6 +24,7 @@
 use std::fs;
 use std::path::PathBuf;
 
+use rustfs::connect::CONNECT_DIAGNOSTIC_CAPABILITIES;
 use sha2::{Digest as _, Sha256};
 
 fn fixture_root() -> PathBuf {
@@ -34,6 +35,31 @@ fn sha256_hex(bytes: &[u8]) -> String {
     Sha256::digest(bytes).iter().map(|byte| format!("{byte:02x}")).collect()
 }
 
+#[test]
+fn heartbeat_producer_capabilities_match_the_frozen_contract() {
+    let fixture: serde_json::Value = serde_json::from_slice(
+        &fs::read(fixture_root().join("heartbeat/producer-capabilities.json")).expect("read producer capabilities fixture"),
+    )
+    .expect("producer capabilities fixture parses");
+    let producer = fixture["producerCapabilities"]
+        .as_array()
+        .expect("producerCapabilities is an array")
+        .iter()
+        .map(|value| value.as_str().expect("producer capability is a string"))
+        .collect::<Vec<_>>();
+    assert_eq!(producer, CONNECT_DIAGNOSTIC_CAPABILITIES);
+
+    let mut expected_heartbeat = vec!["heartbeat", "diagnostics.policy.v1", "inventory.environment@1"];
+    expected_heartbeat.extend(producer);
+    let heartbeat = fixture["heartbeatCapabilities"]
+        .as_array()
+        .expect("heartbeatCapabilities is an array")
+        .iter()
+        .map(|value| value.as_str().expect("heartbeat capability is a string"))
+        .collect::<Vec<_>>();
+    assert_eq!(heartbeat, expected_heartbeat);
+}
+
 /// The registry is closed; adding another set is a protocol change, not a
 /// fixture change. Mirrors `EXPECTED_SETS` in Connect's checker.
 const EXPECTED_SETS: [&str; 13] = [