diff --git a/api/src/main/java/org/fairdatapipeline/api/Object_component_write.java b/api/src/main/java/org/fairdatapipeline/api/Object_component_write.java
index 5204143..327068f 100644
--- a/api/src/main/java/org/fairdatapipeline/api/Object_component_write.java
+++ b/api/src/main/java/org/fairdatapipeline/api/Object_component_write.java
@@ -64,6 +64,9 @@ public CleanableFileChannel writeFileChannel() throws IOException {
    * @param estimateNumber the number to write.
    */
   public void writeEstimate(Number estimateNumber) {
+    if (this.been_used) {
+      throw (new RuntimeException("obj component already written"));
+    }
     var estimate =
         ImmutableEstimate.builder().internalValue(estimateNumber).rng(this.dp.coderun.rng).build();
 
@@ -72,6 +75,7 @@ public void writeEstimate(Number estimateNumber) {
     } catch (IOException e) {
       throw (new RuntimeException("writeEstimate() -- IOException trying to write to file.", e));
     }
+    this.been_used = true;
   }
 
   /**
@@ -80,12 +84,16 @@ public void writeEstimate(Number estimateNumber) {
    * @param distribution the Distribution to write
    */
   public void writeDistribution(Distribution distribution) {
+    if (this.been_used) {
+      throw (new RuntimeException("obj component already written"));
+    }
     try (CleanableFileChannel fileChannel = this.getFileChannel()) {
       this.dp.coderun.parameterDataWriter.write(fileChannel, this.component_name, distribution);
     } catch (IOException e) {
       throw (new RuntimeException(
           "writeDistribution() -- IOException trying to write to file.", e));
     }
+    this.been_used = true;
   }
 
   /**
@@ -94,11 +102,15 @@ public void writeDistribution(Distribution distribution) {
    * @param samples a Samples object containing the samples
    */
   public void writeSamples(Samples samples) {
+    if (this.been_used) {
+      throw (new RuntimeException("obj component already written"));
+    }
     try (CleanableFileChannel fileChannel = this.getFileChannel()) {
       this.dp.coderun.parameterDataWriter.write(fileChannel, this.component_name, samples);
     } catch (IOException e) {
       throw (new RuntimeException("writeSamples() -- IOException trying to write to file.", e));
     }
+    this.been_used = true;
   }
 
   void register_me_in_code_run() {
diff --git a/api/src/test/java/org/fairdatapipeline/api/CoderunIntegrationTest.java b/api/src/test/java/org/fairdatapipeline/api/CoderunIntegrationTest.java
index 6c9bc30..06170b2 100644
--- a/api/src/test/java/org/fairdatapipeline/api/CoderunIntegrationTest.java
+++ b/api/src/test/java/org/fairdatapipeline/api/CoderunIntegrationTest.java
@@ -2,6 +2,7 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
@@ -323,6 +324,19 @@ void check_last_coderun(
     }
   }
 
+  @Test
+  @Order(1)
+  void testWriteEstimateFail() {
+    String dataProduct = "human/population2";
+    String component = "estimate-component";
+    try (Coderun coderun = new Coderun(configPath, scriptPath, token)) {
+      Data_product_write dp = coderun.get_dp_for_write(dataProduct, "toml");
+      Object_component_write oc = dp.getComponent(component);
+      oc.writeEstimate(estimate);
+      assertThrows(RuntimeException.class, () -> oc.writeEstimate(estimate));
+    }
+  }
+
   @Test
   @Order(1)
   void testWriteEstimate() {
@@ -379,6 +393,19 @@ void testReadDistribution() {
     check_last_coderun(List.of(new Triplet<>(dataProduct, component, hash)), null);
   }
 
+  @Test
+  @Order(5)
+  void testWriteCategoricalDistributionFail() {
+    String dataProduct = "human/cdistribution2";
+    String component = "cdistribution-component";
+    try (var coderun = new Coderun(configPath, scriptPath, token)) {
+      Data_product_write dp = coderun.get_dp_for_write(dataProduct, "toml");
+      Object_component_write oc = dp.getComponent(component);
+      oc.writeDistribution(categoricalDistribution);
+      assertThrows(RuntimeException.class, () -> oc.writeDistribution(distribution));
+    }
+  }
+
   @Test
   @Order(5)
   void testWriteCategoricalDistribution() {
@@ -407,6 +434,19 @@ void testReadCategoricalDistribution() {
     check_last_coderun(List.of(new Triplet<>(dataProduct, component, hash)), null);
   }
 
+  @Test
+  @Order(7)
+  void testWriteSamplesFail() throws RuntimeException {
+    String dataProduct = "human/samples2";
+    String component = "example-samples-w";
+    try (var coderun = new Coderun(configPath, scriptPath, token)) {
+      Data_product_write dp = coderun.get_dp_for_write(dataProduct, "toml");
+      Object_component_write oc = dp.getComponent(component);
+      oc.writeSamples(samples2);
+      assertThrows(RuntimeException.class, () -> oc.writeSamples(samples3));
+    }
+  }
+
   @Test
   @Order(7)
   void testWriteSamples() {
diff --git a/api/src/test/resources/config-stdapi.yaml b/api/src/test/resources/config-stdapi.yaml
index bcddb5f..0f44ab5 100644
--- a/api/src/test/resources/config-stdapi.yaml
+++ b/api/src/test/resources/config-stdapi.yaml
@@ -50,6 +50,10 @@ read:
       version: 0.0.1
 
 write:
+  - data_product: human/population2
+    description: Coderun Integration test
+    use:
+      version: 0.0.1
   - data_product: human/population
     description: Coderun Integration test
     use:
@@ -58,6 +62,10 @@ write:
     description: Coderun Integration test for distribution
     use:
       version: 0.0.1
+  - data_product: human/cdistribution2
+    description: Coderun Integration test for cdistribution
+    use:
+      version: 0.0.1
   - data_product: human/cdistribution
     description: Coderun Integration test for cdistribution
     use:
@@ -66,6 +74,10 @@ write:
     description: Coderun Integration test for samples
     use:
       version: 0.0.1
+  - data_product: human/samples2
+    description: Coderun Integration test for samples
+    use:
+      version: 0.0.1
   - data_product: human/multicomp
     description: Coderun Integration test for samples multiple components
     use: