diff --git a/README.md b/README.md
index 9940b2ee8..a287283e9 100644
--- a/README.md
+++ b/README.md
@@ -187,10 +187,11 @@ Helpful commands for development:
 make deps
 ```
 
-### Generate Types and Helpers
+### Generate Types, Client and Server
 ```
 make gen
 ```
+If you want to modify client and server, please modify files under `templates/client` and `templates/server` then run `make gen`
 
 ### Run Tests
 ```
diff --git a/client/api_account.go b/client/api_account.go
index 567206dc5..d6e49a9a9 100644
--- a/client/api_account.go
+++ b/client/api_account.go
@@ -78,18 +78,18 @@ func (a *AccountAPIService) AccountBalance(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -97,7 +97,11 @@ func (a *AccountAPIService) AccountBalance(
 		var v types.AccountBalanceResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -105,23 +109,27 @@ func (a *AccountAPIService) AccountBalance(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
@@ -173,18 +181,18 @@ func (a *AccountAPIService) AccountCoins(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -192,7 +200,11 @@ func (a *AccountAPIService) AccountCoins(
 		var v types.AccountCoinsResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -200,23 +212,27 @@ func (a *AccountAPIService) AccountCoins(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
diff --git a/client/api_block.go b/client/api_block.go
index 04db91539..d42f7a02a 100644
--- a/client/api_block.go
+++ b/client/api_block.go
@@ -75,18 +75,18 @@ func (a *BlockAPIService) Block(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -94,7 +94,11 @@ func (a *BlockAPIService) Block(
 		var v types.BlockResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -102,23 +106,27 @@ func (a *BlockAPIService) Block(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
@@ -173,18 +181,18 @@ func (a *BlockAPIService) BlockTransaction(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -192,7 +200,11 @@ func (a *BlockAPIService) BlockTransaction(
 		var v types.BlockTransactionResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -200,23 +212,27 @@ func (a *BlockAPIService) BlockTransaction(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
diff --git a/client/api_call.go b/client/api_call.go
index bbece7f3e..f8ae99684 100644
--- a/client/api_call.go
+++ b/client/api_call.go
@@ -78,18 +78,18 @@ func (a *CallAPIService) Call(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -97,7 +97,11 @@ func (a *CallAPIService) Call(
 		var v types.CallResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -105,23 +109,27 @@ func (a *CallAPIService) Call(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
diff --git a/client/api_construction.go b/client/api_construction.go
index cc5ef08ae..05b1c0ffc 100644
--- a/client/api_construction.go
+++ b/client/api_construction.go
@@ -70,18 +70,18 @@ func (a *ConstructionAPIService) ConstructionCombine(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -89,7 +89,11 @@ func (a *ConstructionAPIService) ConstructionCombine(
 		var v types.ConstructionCombineResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -97,23 +101,27 @@ func (a *ConstructionAPIService) ConstructionCombine(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
@@ -156,18 +164,18 @@ func (a *ConstructionAPIService) ConstructionDerive(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -175,7 +183,11 @@ func (a *ConstructionAPIService) ConstructionDerive(
 		var v types.ConstructionDeriveResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -183,23 +195,27 @@ func (a *ConstructionAPIService) ConstructionDerive(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
@@ -242,18 +258,18 @@ func (a *ConstructionAPIService) ConstructionHash(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -261,7 +277,11 @@ func (a *ConstructionAPIService) ConstructionHash(
 		var v types.TransactionIdentifierResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -269,23 +289,27 @@ func (a *ConstructionAPIService) ConstructionHash(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
@@ -335,18 +359,18 @@ func (a *ConstructionAPIService) ConstructionMetadata(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -354,7 +378,11 @@ func (a *ConstructionAPIService) ConstructionMetadata(
 		var v types.ConstructionMetadataResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -362,23 +390,27 @@ func (a *ConstructionAPIService) ConstructionMetadata(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
@@ -422,18 +454,18 @@ func (a *ConstructionAPIService) ConstructionParse(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -441,7 +473,11 @@ func (a *ConstructionAPIService) ConstructionParse(
 		var v types.ConstructionParseResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -449,23 +485,27 @@ func (a *ConstructionAPIService) ConstructionParse(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
@@ -514,18 +554,18 @@ func (a *ConstructionAPIService) ConstructionPayloads(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -533,7 +573,11 @@ func (a *ConstructionAPIService) ConstructionPayloads(
 		var v types.ConstructionPayloadsResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -541,23 +585,27 @@ func (a *ConstructionAPIService) ConstructionPayloads(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
@@ -604,18 +652,18 @@ func (a *ConstructionAPIService) ConstructionPreprocess(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -623,7 +671,11 @@ func (a *ConstructionAPIService) ConstructionPreprocess(
 		var v types.ConstructionPreprocessResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -631,23 +683,27 @@ func (a *ConstructionAPIService) ConstructionPreprocess(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
@@ -693,18 +749,18 @@ func (a *ConstructionAPIService) ConstructionSubmit(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -712,7 +768,11 @@ func (a *ConstructionAPIService) ConstructionSubmit(
 		var v types.TransactionIdentifierResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -720,23 +780,27 @@ func (a *ConstructionAPIService) ConstructionSubmit(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
diff --git a/client/api_events.go b/client/api_events.go
index 1d3e38e31..086b7dbbd 100644
--- a/client/api_events.go
+++ b/client/api_events.go
@@ -73,18 +73,18 @@ func (a *EventsAPIService) EventsBlocks(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -92,7 +92,11 @@ func (a *EventsAPIService) EventsBlocks(
 		var v types.EventsBlocksResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -100,23 +104,27 @@ func (a *EventsAPIService) EventsBlocks(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
diff --git a/client/api_mempool.go b/client/api_mempool.go
index 727f708bc..b694c6823 100644
--- a/client/api_mempool.go
+++ b/client/api_mempool.go
@@ -68,18 +68,18 @@ func (a *MempoolAPIService) Mempool(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -87,7 +87,11 @@ func (a *MempoolAPIService) Mempool(
 		var v types.MempoolResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -95,23 +99,27 @@ func (a *MempoolAPIService) Mempool(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
@@ -159,18 +167,18 @@ func (a *MempoolAPIService) MempoolTransaction(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -178,7 +186,11 @@ func (a *MempoolAPIService) MempoolTransaction(
 		var v types.MempoolTransactionResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -186,23 +198,27 @@ func (a *MempoolAPIService) MempoolTransaction(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
diff --git a/client/api_network.go b/client/api_network.go
index 8e644b573..a471b4aab 100644
--- a/client/api_network.go
+++ b/client/api_network.go
@@ -68,18 +68,18 @@ func (a *NetworkAPIService) NetworkList(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -87,7 +87,11 @@ func (a *NetworkAPIService) NetworkList(
 		var v types.NetworkListResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -95,23 +99,27 @@ func (a *NetworkAPIService) NetworkList(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
@@ -156,18 +164,18 @@ func (a *NetworkAPIService) NetworkOptions(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -175,7 +183,11 @@ func (a *NetworkAPIService) NetworkOptions(
 		var v types.NetworkOptionsResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -183,23 +195,27 @@ func (a *NetworkAPIService) NetworkOptions(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
@@ -242,18 +258,18 @@ func (a *NetworkAPIService) NetworkStatus(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -261,7 +277,11 @@ func (a *NetworkAPIService) NetworkStatus(
 		var v types.NetworkStatusResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -269,23 +289,27 @@ func (a *NetworkAPIService) NetworkStatus(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
diff --git a/client/api_search.go b/client/api_search.go
index cb07192e7..a84d0068e 100644
--- a/client/api_search.go
+++ b/client/api_search.go
@@ -73,18 +73,18 @@ func (a *SearchAPIService) SearchTransactions(
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -92,7 +92,11 @@ func (a *SearchAPIService) SearchTransactions(
 		var v types.SearchTransactionsResponse
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 200, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
 		return &v, nil, nil
@@ -100,23 +104,27 @@ func (a *SearchAPIService) SearchTransactions(
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf(
+				"failed to decode when hit status code 500, response body %s: %w",
+				string(localVarBody),
+				err,
+			)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
diff --git a/client/client.go b/client/client.go
index 9ce83b264..b79797231 100644
--- a/client/client.go
+++ b/client/client.go
@@ -151,7 +151,7 @@ func (c *APIClient) callAPI(ctx context.Context, request *http.Request) (*http.R
 		log.Printf("\n%s\n", string(dump))
 	}
 
-	return resp, err
+	return resp, nil
 }
 
 // ChangeBasePath changes base path to allow switching to mocks
@@ -185,14 +185,14 @@ func (c *APIClient) prepareRequest(
 
 		body, err = setBody(postBody, contentType)
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("failed to set body: %w", err)
 		}
 	}
 
 	// Setup path and query parameters
 	url, err := url.Parse(path)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to parse path %s: %w", path, err)
 	}
 
 	// Override request host, if applicable
@@ -208,7 +208,7 @@ func (c *APIClient) prepareRequest(
 	// Generate a new request
 	localVarRequest, err = http.NewRequest(http.MethodPost, url.String(), body)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to generate new request: %w", err)
 	}
 
 	// add header parameters, if any
@@ -247,7 +247,7 @@ func (c *APIClient) decode(v interface{}, b []byte, contentType string) (err err
 
 	if jsonCheck.MatchString(contentType) {
 		if err = json.Unmarshal(b, v); err != nil {
-			return err
+			return fmt.Errorf("failed to unmarshal: %w", err)
 		}
 		return nil
 	}
@@ -278,8 +278,7 @@ func setBody(body interface{}, contentType string) (bodyBuf *bytes.Buffer, err e
 	}
 
 	if bodyBuf.Len() == 0 {
-		err = fmt.Errorf("invalid body type %s", contentType)
-		return nil, err
+		return nil, fmt.Errorf("invalid body type %s", contentType)
 	}
 	return bodyBuf, nil
 }
diff --git a/client/configuration.go b/client/configuration.go
index 9c4086eb0..0d4d218d6 100644
--- a/client/configuration.go
+++ b/client/configuration.go
@@ -114,8 +114,8 @@ func (c *Configuration) AddDefaultHeader(key string, value string) {
 
 // ServerURL returns URL based on server settings
 func (c *Configuration) ServerURL(index int, variables map[string]string) (string, error) {
-	if index < 0 || len(c.Servers) <= index {
-		return "", fmt.Errorf("Index %v out of range %v", index, len(c.Servers)-1)
+	if index < 0 || index >= len(c.Servers) {
+		return "", fmt.Errorf("index %d out of range [0-%d]", index, len(c.Servers)-1)
 	}
 	server := c.Servers[index]
 	url := server.URL
@@ -131,7 +131,7 @@ func (c *Configuration) ServerURL(index int, variables map[string]string) (strin
 			}
 			if !found {
 				return "", fmt.Errorf(
-					"The variable %s in the server URL has invalid value %v. Must be %v",
+					"the variable %s in the server URL has invalid value %s. Must be %v",
 					name,
 					value,
 					variable.EnumValues,
diff --git a/templates/client/api.mustache b/templates/client/api.mustache
index 7002bc1d0..1532edf2e 100644
--- a/templates/client/api.mustache
+++ b/templates/client/api.mustache
@@ -74,18 +74,18 @@ func (a *{{{classname}}}Service) {{{nickname}}}(ctx _context.Context{{#hasParams
 
 	r, err := a.client.prepareRequest(ctx, localVarPath, localVarPostBody, localVarHeaderParams)
 	if err != nil {
-    return nil, nil, err
+    return nil, nil, fmt.Errorf("failed to prepare request: %w", err)
 	}
 
 	localVarHTTPResponse, err := a.client.callAPI(ctx, r)
 	if err != nil || localVarHTTPResponse == nil {
-    return nil, nil, err
+    return nil, nil, fmt.Errorf("failed to call API: %w", err)
 	}
 
 	localVarBody, err := _ioutil.ReadAll(localVarHTTPResponse.Body)
 	defer localVarHTTPResponse.Body.Close()
 	if err != nil {
-    return nil, nil, err 
+    return nil, nil, fmt.Errorf("failed to read response: %w", err) 
 	}
 
 	switch localVarHTTPResponse.StatusCode {
@@ -95,7 +95,7 @@ func (a *{{{classname}}}Service) {{{nickname}}}(ctx _context.Context{{#hasParams
     {{/returnType}}
     err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
     if err != nil {
-      return nil, nil, err
+      return nil, nil, fmt.Errorf("failed to decode when hit status code 200, response body %s: %w", string(localVarBody), err)
     }
 
     return &v, nil, nil
@@ -103,23 +103,23 @@ func (a *{{{classname}}}Service) {{{nickname}}}(ctx _context.Context{{#hasParams
 		var v types.Error
 		err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, fmt.Errorf("failed to decode when hit status code 500, response body %s: %w", string(localVarBody), err)
 		}
 
-		return nil, &v, fmt.Errorf("%+v", v)
+		return nil, &v, fmt.Errorf("error %+v", v)
 	case _nethttp.StatusBadGateway,
 		_nethttp.StatusServiceUnavailable,
 		_nethttp.StatusGatewayTimeout,
 		_nethttp.StatusRequestTimeout:
 		return nil, nil, fmt.Errorf(
-			"%w: code: %d body: %s",
-			ErrRetriable,
+			"status code %d, response body %s: %w",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
+			ErrRetriable,
 		)
 	default:
 		return nil, nil, fmt.Errorf(
-			"invalid status code: %d body: %s",
+			"invalid status code %d, response body %s",
 			localVarHTTPResponse.StatusCode,
 			string(localVarBody),
 		)
diff --git a/templates/client/client.mustache b/templates/client/client.mustache
index 7caab62b4..548a93bbc 100644
--- a/templates/client/client.mustache
+++ b/templates/client/client.mustache
@@ -127,7 +127,7 @@ func (c *APIClient) callAPI(ctx context.Context, request *http.Request) (*http.R
 		log.Printf("\n%s\n", string(dump))
 	}
 
-	return resp, err
+	return resp, nil
 }
 
 // ChangeBasePath changes base path to allow switching to mocks
@@ -160,14 +160,14 @@ func (c *APIClient) prepareRequest(
 
 		body, err = setBody(postBody, contentType)
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("failed to set body: %w", err)
 		}
 	}
 
 	// Setup path and query parameters
 	url, err := url.Parse(path)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to parse path %s: %w", path, err)
 	}
 
 	// Override request host, if applicable
@@ -183,7 +183,7 @@ func (c *APIClient) prepareRequest(
 	// Generate a new request
 	localVarRequest, err = http.NewRequest(http.MethodPost, url.String(), body)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to generate new request: %w", err)
 	}
 
 	// add header parameters, if any
@@ -222,7 +222,7 @@ func (c *APIClient) decode(v interface{}, b []byte, contentType string) (err err
 
 	if jsonCheck.MatchString(contentType) {
 		if err = json.Unmarshal(b, v); err != nil {
-			return err
+			return fmt.Errorf("failed to unmarshal: %w", err)
 		}
 		return nil
 	}
@@ -253,8 +253,7 @@ func setBody(body interface{}, contentType string) (bodyBuf *bytes.Buffer, err e
 	}
 
 	if bodyBuf.Len() == 0 {
-		err = fmt.Errorf("invalid body type %s", contentType)
-		return nil, err
+		return nil, fmt.Errorf("invalid body type %s", contentType)
 	}
 	return bodyBuf, nil
 }
diff --git a/templates/client/configuration.mustache b/templates/client/configuration.mustache
index a985dd15e..5773083fd 100644
--- a/templates/client/configuration.mustache
+++ b/templates/client/configuration.mustache
@@ -139,8 +139,8 @@ func (c *Configuration) AddDefaultHeader(key string, value string) {
 
 // ServerUrl returns URL based on server settings
 func (c *Configuration) ServerUrl(index int, variables map[string]string) (string, error) {
-	if index < 0 || len(c.Servers) <= index {
-		return "", fmt.Errorf("Index %v out of range %v", index, len(c.Servers) - 1)
+	if index < 0 || index >= len(c.Servers) {
+		return "", fmt.Errorf("index %d out of range [0-%d]", index, len(c.Servers)-1)
 	}
 	server := c.Servers[index]
 	url := server.Url
@@ -155,7 +155,7 @@ func (c *Configuration) ServerUrl(index int, variables map[string]string) (strin
 				}
 			}
 			if !found {
-				return "", fmt.Errorf("The variable %s in the server URL has invalid value %v. Must be %v", name, value, variable.EnumValues)
+				return "", fmt.Errorf("the variable %s in the server URL has invalid value %s. Must be %v", name, value, variable.EnumValues)
 			}
 			url = strings.ReplaceAll(url, "{"+name+"}", value)
 		} else {