diff --git a/README.md b/README.md
index 981f972..a39e0e4 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,11 @@ ruby 1.9.3+
     tags: { factor: 'awesome', host: 'ponies' }
   }
 
+  # Query one metric
   @client.put(sample)
+
+  # Query many metrics
+  @client.put([sample, sample])
 ```
 
 ## License
diff --git a/lib/opentsdb/client.rb b/lib/opentsdb/client.rb
index 1fb4a6c..f52ce94 100644
--- a/lib/opentsdb/client.rb
+++ b/lib/opentsdb/client.rb
@@ -16,6 +16,10 @@ def initialize(options = {})
     end
 
     def to_command(options)
+      if !options.key?(:tags) || !options[:tags].is_a?(Hash) || options[:tags].empty?
+        fail OpenTSDB::Errors::InvalidTagsError
+      end
+
       timestamp   = options[:timestamp].to_i
       metric_name = options[:metric]
       value       = options[:value].to_f
diff --git a/lib/opentsdb/errors.rb b/lib/opentsdb/errors.rb
index 2ede806..ba9ace8 100644
--- a/lib/opentsdb/errors.rb
+++ b/lib/opentsdb/errors.rb
@@ -5,5 +5,11 @@ def to_s
         'Unable to connect or invalid connection data'
       end
     end
+
+    class InvalidTagsError < StandardError
+      def to_s
+        'The tags you provided are invalid. Note that you need at least one tag to proceed.'
+      end
+    end
   end
 end
diff --git a/spec/client_spec.rb b/spec/client_spec.rb
index f648d2f..fba86e3 100644
--- a/spec/client_spec.rb
+++ b/spec/client_spec.rb
@@ -8,8 +8,12 @@
     allow(TCPSocket).to receive(:new).and_return(socket)
   end
 
-  describe 'error handling' do
-    subject { described_class.new }
+  describe '#initialize' do
+    subject { client }
+
+    it 'creates a new client' do
+      expect { subject }.to_not raise_error
+    end
 
     it 'raises a custom error if the connection failed' do
       expect(TCPSocket).to receive(:new).and_raise('connection error')
@@ -18,43 +22,59 @@
     end
   end
 
-  it 'creates a new client' do
-    expect { client }.to_not raise_error
-  end
+  describe '#put' do
+    let(:metric) do
+      { timestamp: 1_411_104_988, metric: 'users', value: 100, tags: { foo: 'bar' } }
+    end
+
+    let(:other_metric) do
+      { timestamp: 1_411_104_999, metric: 'users', value: 150, tags: { bar: 'baz' } }
+    end
 
-  it 'writes a single metric to the socket' do
-    expect(socket).to receive(:puts).with('put users 1411104988 100.0 foo=bar')
+    describe 'error handling' do
+      context 'no tags' do
+        subject { client.put({}) }
 
-    metric = {
-      timestamp: 1411104988,
-      metric: 'users',
-      value: 100,
-      tags: { foo: 'bar' },
-    }
+        it { expect { subject }.to raise_error(OpenTSDB::Errors::InvalidTagsError) }
+      end
 
-    client.put(metric)
-  end
+      context 'tags' do
+        subject { client.put(metric.merge(tags: tags)) }
+
+        context 'empty tags' do
+          let(:tags) { {} }
+
+          it { expect { subject }.to raise_error(OpenTSDB::Errors::InvalidTagsError) }
+        end
+
+        context 'invalid tags' do
+          let(:tags) { [:test, 123] }
 
-  it 'writes multiple metrics to the socket' do
-    expect(socket).to receive(:puts).with(
-      "put users 1411104988 100.0 foo=bar\nput users 1411104999 150.0 bar=baz"
-    )
-
-    metrics = [
-      {
-        timestamp: 1411104988,
-        metric: 'users',
-        value: 100,
-        tags: { foo: 'bar' },
-      },
-      {
-        timestamp: 1411104999,
-        metric: 'users',
-        value: 150,
-        tags: { bar: 'baz' },
-      },
-    ]
-
-    client.put(metrics)
+          it { expect { subject }.to raise_error(OpenTSDB::Errors::InvalidTagsError) }
+        end
+      end
+    end
+
+    context 'one metric' do
+      subject { client.put(metric) }
+
+      it 'writes a single metric to the socket' do
+        expect(socket).to receive(:puts).with('put users 1411104988 100.0 foo=bar')
+
+        subject
+      end
+    end
+
+    context 'many metrics' do
+      subject { client.put([metric, other_metric]) }
+
+      it 'writes multiple metrics to the socket' do
+        expect(socket).to receive(:puts).with(
+          "put users 1411104988 100.0 foo=bar\nput users 1411104999 150.0 bar=baz"
+        )
+
+        subject
+      end
+    end
   end
 end