fix(openai): don't double marshel responses api

providers/openai/responses_language_model.go

@@ -3,7 +3,6 @@ package openai
 import (
 	"context"
 	"encoding/base64"
-	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
@@ -551,16 +550,7 @@ func toResponsesPrompt(prompt fantasy.Prompt, systemMessageMode string, store bo
 						continue
 					}
 
-					inputJSON, err := json.Marshal(toolCallPart.Input)
-					if err != nil {
-						warnings = append(warnings, fantasy.CallWarning{
-							Type:    fantasy.CallWarningTypeOther,
-							Message: fmt.Sprintf("failed to marshal tool call input: %v", err),
-						})
-						continue
-					}
-
-					input = append(input, responses.ResponseInputItemParamOfFunctionCall(string(inputJSON), toolCallPart.ToolCallID, toolCallPart.ToolName))
+					input = append(input, responses.ResponseInputItemParamOfFunctionCall(toolCallPart.Input, toolCallPart.ToolCallID, toolCallPart.ToolName))
 				case fantasy.ContentTypeSource:
 					// Source citations from web search are not a
 					// recognised Responses API input type; skip.

providertests/azure_test.go

@@ -19,7 +19,6 @@ func TestAzureCommon(t *testing.T) {
 	testCommon(t, []builderPair{
 		{"azure-o4-mini", builderAzureO4Mini, nil, nil},
 		{"azure-gpt-5-mini", builderAzureGpt5Mini, nil, nil},
-		{"azure-grok-3-mini", builderAzureGrok3Mini, nil, nil},
 	})
 }
 
@@ -31,7 +30,6 @@ func TestAzureThinking(t *testing.T) {
 	}
 	testThinking(t, []builderPair{
 		{"azure-gpt-5-mini", builderAzureGpt5Mini, opts, nil},
-		{"azure-grok-3-mini", builderAzureGrok3Mini, opts, nil},
 	}, testAzureThinking)
 }
 
@@ -62,15 +60,3 @@ func builderAzureGpt5Mini(t *testing.T, r *vcr.Recorder) (fantasy.LanguageModel,
 	}
 	return provider.LanguageModel(t.Context(), "gpt-5-mini")
 }
-
-func builderAzureGrok3Mini(t *testing.T, r *vcr.Recorder) (fantasy.LanguageModel, error) {
-	provider, err := azure.New(
-		azure.WithBaseURL(cmp.Or(os.Getenv("FANTASY_AZURE_BASE_URL"), defaultBaseURL)),
-		azure.WithAPIKey(cmp.Or(os.Getenv("FANTASY_AZURE_API_KEY"), "(missing)")),
-		azure.WithHTTPClient(&http.Client{Transport: r}),
-	)
-	if err != nil {
-		return nil, err
-	}
-	return provider.LanguageModel(t.Context(), "grok-3-mini")
-}