diff --git a/lib/towerops/proto/agent.pb.ex b/lib/towerops/proto/agent.pb.ex
index d1d5e32a..36d26213 100644
--- a/lib/towerops/proto/agent.pb.ex
+++ b/lib/towerops/proto/agent.pb.ex
@@ -38,6 +38,7 @@ defmodule Towerops.Agent.AgentConfig do
   field :version, 1, type: :string
   field :poll_interval_seconds, 2, type: :uint32, json_name: "pollIntervalSeconds"
   field :devices, 3, repeated: true, type: Towerops.Agent.Device
+  field :checks, 4, repeated: true, type: Towerops.Agent.Check
 end
 
 defmodule Towerops.Agent.Device do
@@ -71,6 +72,7 @@ defmodule Towerops.Agent.SnmpConfig do
   field :version, 2, type: :string
   field :community, 3, type: :string
   field :port, 4, type: :uint32
+  field :transport, 5, type: :string
 end
 
 defmodule Towerops.Agent.Sensor.MetadataEntry do
@@ -155,6 +157,11 @@ defmodule Towerops.Agent.Metric do
     type: Towerops.Agent.MonitoringCheck,
     json_name: "monitoringCheck",
     oneof: 0
+
+  field :check_result, 5,
+    type: Towerops.Agent.CheckResult,
+    json_name: "checkResult",
+    oneof: 0
 end
 
 defmodule Towerops.Agent.SensorReading do
@@ -298,6 +305,7 @@ defmodule Towerops.Agent.SnmpDevice do
   field :v3_auth_password, 8, type: :string, json_name: "v3AuthPassword"
   field :v3_priv_protocol, 9, type: :string, json_name: "v3PrivProtocol"
   field :v3_priv_password, 10, type: :string, json_name: "v3PrivPassword"
+  field :transport, 11, type: :string
 end
 
 defmodule Towerops.Agent.SnmpQuery do
@@ -472,3 +480,109 @@ defmodule Towerops.Agent.MikrotikSentence do
     type: Towerops.Agent.MikrotikSentence.AttributesEntry,
     map: true
 end
+
+# Service Checks (HTTP/TCP/DNS)
+
+defmodule Towerops.Agent.Check do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.Check",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  oneof(:config, 0)
+
+  field :id, 1, type: :string
+  field :check_type, 2, type: :string, json_name: "checkType"
+  field :interval_seconds, 3, type: :uint32, json_name: "intervalSeconds"
+  field :timeout_ms, 4, type: :uint32, json_name: "timeoutMs"
+  field :http, 5, type: Towerops.Agent.HttpCheckConfig, oneof: 0
+  field :tcp, 6, type: Towerops.Agent.TcpCheckConfig, oneof: 0
+  field :dns, 7, type: Towerops.Agent.DnsCheckConfig, oneof: 0
+end
+
+defmodule Towerops.Agent.HttpCheckConfig.HeadersEntry do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.HttpCheckConfig.HeadersEntry",
+    map: true,
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :key, 1, type: :string
+  field :value, 2, type: :string
+end
+
+defmodule Towerops.Agent.HttpCheckConfig do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.HttpCheckConfig",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :url, 1, type: :string
+  field :method, 2, type: :string
+  field :expected_status, 3, type: :uint32, json_name: "expectedStatus"
+  field :verify_ssl, 4, type: :bool, json_name: "verifySsl"
+  field :headers, 5, repeated: true, type: Towerops.Agent.HttpCheckConfig.HeadersEntry, map: true
+  field :body, 6, type: :string
+  field :regex, 7, type: :string
+  field :follow_redirects, 8, type: :bool, json_name: "followRedirects"
+end
+
+defmodule Towerops.Agent.TcpCheckConfig do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.TcpCheckConfig",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :host, 1, type: :string
+  field :port, 2, type: :uint32
+  field :send, 3, type: :string
+  field :expect, 4, type: :string
+end
+
+defmodule Towerops.Agent.DnsCheckConfig do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.DnsCheckConfig",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :hostname, 1, type: :string
+  field :server, 2, type: :string
+  field :record_type, 3, type: :string, json_name: "recordType"
+  field :expected, 4, type: :string
+end
+
+defmodule Towerops.Agent.CheckResult do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.CheckResult",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :check_id, 1, type: :string, json_name: "checkId"
+  field :status, 2, type: :uint32
+  field :output, 3, type: :string
+  field :response_time_ms, 4, type: :double, json_name: "responseTimeMs"
+  field :timestamp, 5, type: :int64
+end
+
+defmodule Towerops.Agent.CheckList do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.CheckList",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :checks, 1, repeated: true, type: Towerops.Agent.Check
+end
diff --git a/priv/proto/agent.proto b/priv/proto/agent.proto
index dcca9113..47cf6b40 100644
--- a/priv/proto/agent.proto
+++ b/priv/proto/agent.proto
@@ -7,6 +7,7 @@ message AgentConfig {
   string version = 1;
   uint32 poll_interval_seconds = 2;
   repeated Device devices = 3;
+  repeated Check checks = 4;  // Service checks (HTTP/TCP/DNS)
 }
 
 message Device {
@@ -26,6 +27,7 @@ message SnmpConfig {
   string version = 2;
   string community = 3;
   uint32 port = 4;
+  string transport = 5;
 }
 
 message Sensor {
@@ -54,6 +56,7 @@ message Metric {
     InterfaceStat interface_stat = 2;
     NeighborDiscovery neighbor_discovery = 3;
     MonitoringCheck monitoring_check = 4;
+    CheckResult check_result = 5;  // Service check results (HTTP/TCP/DNS)
   }
 }
 
@@ -96,6 +99,59 @@ message MonitoringCheck {
   int64 timestamp = 4; // Unix timestamp in seconds
 }
 
+// Service Checks (HTTP/TCP/DNS)
+
+message Check {
+  string id = 1;
+  string check_type = 2;  // "http", "tcp", "dns"
+  uint32 interval_seconds = 3;
+  uint32 timeout_ms = 4;
+
+  // Type-specific config (JSON from Phoenix config field)
+  oneof config {
+    HttpCheckConfig http = 5;
+    TcpCheckConfig tcp = 6;
+    DnsCheckConfig dns = 7;
+  }
+}
+
+message HttpCheckConfig {
+  string url = 1;
+  string method = 2;  // GET, POST, etc.
+  uint32 expected_status = 3;
+  bool verify_ssl = 4;
+  map<string, string> headers = 5;
+  string body = 6;
+  string regex = 7;  // Content match regex
+  bool follow_redirects = 8;
+}
+
+message TcpCheckConfig {
+  string host = 1;
+  uint32 port = 2;
+  string send = 3;  // Data to send after connection
+  string expect = 4;  // Expected response
+}
+
+message DnsCheckConfig {
+  string hostname = 1;
+  string server = 2;  // DNS server (optional)
+  string record_type = 3;  // A, AAAA, CNAME, MX, TXT
+  string expected = 4;  // Expected result (optional)
+}
+
+message CheckResult {
+  string check_id = 1;
+  uint32 status = 2;  // 0=OK, 1=WARNING, 2=CRITICAL, 3=UNKNOWN
+  string output = 3;
+  double response_time_ms = 4;
+  int64 timestamp = 5;  // Unix timestamp in seconds
+}
+
+message CheckList {
+  repeated Check checks = 1;
+}
+
 // Heartbeat metadata
 message HeartbeatMetadata {
   string version = 1;
@@ -149,6 +205,7 @@ message SnmpDevice {
   string v3_auth_password = 8;   // Decrypted before sending
   string v3_priv_protocol = 9;   // "DES" | "AES" | "AES-256" | etc.
   string v3_priv_password = 10;  // Decrypted before sending
+  string transport = 11;          // "udp" | "tcp"
 }
 
 message SnmpQuery {
@@ -169,6 +226,7 @@ message AgentHeartbeat {
   string hostname = 2;
   uint64 uptime_seconds = 3;
   string ip_address = 4;
+  string arch = 5;
 }
 
 message AgentError {