diff --git a/tests/dotnet/azure-openai/Program.cs b/tests/dotnet/azure-openai/Program.cs
index d6987cb1..6ba44270 100644
--- a/tests/dotnet/azure-openai/Program.cs
+++ b/tests/dotnet/azure-openai/Program.cs
@@ -271,17 +271,13 @@ static async Task RunPrototype()
             };
             options.Tools.Add(weatherTool);
 
-            // Derive from options.Tools — the same collection passed to CompleteChatAsync (OpenAI function-calling format)
             var toolDefinitionsJson = JsonSerializer.Serialize(
                 options.Tools.Select(t => new Dictionary<string, object>
                 {
                     ["type"] = "function",
-                    ["function"] = new
-                    {
-                        name = t.FunctionName,
-                        description = t.FunctionDescription,
-                        parameters = JsonSerializer.Deserialize<JsonElement>(t.FunctionParameters)
-                    }
+                    ["name"] = t.FunctionName,
+                    ["description"] = t.FunctionDescription,
+                    ["parameters"] = JsonSerializer.Deserialize<JsonElement>(t.FunctionParameters)
                 }).ToArray()
             );
             activity?.SetTag("gen_ai.operation.name", "chat");
diff --git a/tests/dotnet/extensions-ai/Program.cs b/tests/dotnet/extensions-ai/Program.cs
index 6e5b030d..1785fa84 100644
--- a/tests/dotnet/extensions-ai/Program.cs
+++ b/tests/dotnet/extensions-ai/Program.cs
@@ -270,17 +270,13 @@ static async Task RunPrototype()
             };
             options.Tools.Add(weatherTool);
 
-            // Derive from options.Tools — the same collection passed to CompleteChatAsync (OpenAI function-calling format)
             var toolDefinitionsJson = JsonSerializer.Serialize(
                 options.Tools.Select(t => new Dictionary<string, object>
                 {
                     ["type"] = "function",
-                    ["function"] = new
-                    {
-                        name = t.FunctionName,
-                        description = t.FunctionDescription,
-                        parameters = JsonSerializer.Deserialize<JsonElement>(t.FunctionParameters)
-                    }
+                    ["name"] = t.FunctionName,
+                    ["description"] = t.FunctionDescription,
+                    ["parameters"] = JsonSerializer.Deserialize<JsonElement>(t.FunctionParameters)
                 }).ToArray()
             );
             activity?.SetTag("gen_ai.operation.name", "chat");
diff --git a/tests/dotnet/semantic-kernel/Program.cs b/tests/dotnet/semantic-kernel/Program.cs
index 7b938777..5c19f15b 100644
--- a/tests/dotnet/semantic-kernel/Program.cs
+++ b/tests/dotnet/semantic-kernel/Program.cs
@@ -292,28 +292,23 @@ static async Task RunPrototype()
         using (var activity = s_manualActivitySource.StartActivity("chat gpt-4o-mini"))
         {
             var endpoint = new Uri(mockBaseUrl);
-            // Semantic Kernel converts plugins to OpenAI function-calling format
-            // before sending to the API, so we mirror that shape here.
             var toolDefinitionsJson = JsonSerializer.Serialize(
                 kernel.Plugins
                     .SelectMany(p => p)
                     .Select(f => new Dictionary<string, object>
                     {
                         ["type"] = "function",
-                        ["function"] = new
+                        ["name"] = f.Name,
+                        ["description"] = f.Description,
+                        ["parameters"] = new
                         {
-                            name = f.Name,
-                            description = f.Description,
-                            parameters = new
-                            {
-                                type = "object",
-                                properties = f.Metadata.Parameters.ToDictionary(
-                                    p => p.Name,
-                                    p => new { type = ToJsonSchemaType(p.ParameterType) }),
-                                required = f.Metadata.Parameters
-                                    .Where(p => p.IsRequired)
-                                    .Select(p => p.Name)
-                            }
+                            type = "object",
+                            properties = f.Metadata.Parameters.ToDictionary(
+                                p => p.Name,
+                                p => new { type = ToJsonSchemaType(p.ParameterType) }),
+                            required = f.Metadata.Parameters
+                                .Where(p => p.IsRequired)
+                                .Select(p => p.Name)
                         }
                     }));
             activity?.SetTag("gen_ai.operation.name", "chat");
diff --git a/tests/java/aws-bedrock/src/main/java/com/example/bedrocktest/AwsBedrockPrototypeTest.java b/tests/java/aws-bedrock/src/main/java/com/example/bedrocktest/AwsBedrockPrototypeTest.java
index ac427013..b30302bf 100644
--- a/tests/java/aws-bedrock/src/main/java/com/example/bedrocktest/AwsBedrockPrototypeTest.java
+++ b/tests/java/aws-bedrock/src/main/java/com/example/bedrocktest/AwsBedrockPrototypeTest.java
@@ -161,9 +161,9 @@ static void runConverseToolCall(BedrockRuntimeClient client) {
         ToolConfiguration toolConfig = ToolConfiguration.builder()
                 .tools(Tool.builder().toolSpec(toolSpec).build())
                 .build();
-        String toolDefinitionsJson = "[{\"toolSpec\":{\"name\":\"get_weather\",\"description\":\"Get the current weather\"," +
-                "\"inputSchema\":{\"json\":{\"type\":\"object\",\"properties\":{\"location\":{\"type\":\"string\"," +
-                "\"description\":\"City name\"}},\"required\":[\"location\"]}}}}]";
+        String toolDefinitionsJson = "[{\"type\":\"function\",\"name\":\"get_weather\",\"description\":\"Get the current weather\"," +
+                "\"parameters\":{\"type\":\"object\",\"properties\":{\"location\":{\"type\":\"string\"," +
+                "\"description\":\"City name\"}},\"required\":[\"location\"]}}]";
         Span span = tracer.spanBuilder("chat " + modelId).startSpan();
         try {
             try (var scope = span.makeCurrent()) {
diff --git a/tests/java/openai/src/main/java/com/example/openaitest/OpenAiPrototypeTest.java b/tests/java/openai/src/main/java/com/example/openaitest/OpenAiPrototypeTest.java
index 80184029..d10edbba 100644
--- a/tests/java/openai/src/main/java/com/example/openaitest/OpenAiPrototypeTest.java
+++ b/tests/java/openai/src/main/java/com/example/openaitest/OpenAiPrototypeTest.java
@@ -215,10 +215,18 @@ static void runChatToolCall(OpenAIClient client) {
                                 .build())
                         .build())
                 .build();
-        // Derive from params.tools() — the same tools passed to the API call
         String toolDefinitionsJson;
         try {
-            toolDefinitionsJson = ObjectMappers.jsonMapper().writeValueAsString(params.tools().orElse(List.of()));
+            var toolDefs = params.tools().orElse(List.of()).stream().map(tool -> {
+                var fn = tool.asFunction().function();
+                var def = new java.util.LinkedHashMap<String, Object>();
+                def.put("type", "function");
+                def.put("name", fn.name());
+                fn.description().ifPresent(d -> def.put("description", d));
+                fn.parameters().ifPresent(p -> def.put("parameters", p));
+                return def;
+            }).toList();
+            toolDefinitionsJson = ObjectMappers.jsonMapper().writeValueAsString(toolDefs);
         } catch (JsonProcessingException e) {
             throw new RuntimeException(e);
         }
diff --git a/tests/js/anthropic/test_prototype.ts b/tests/js/anthropic/test_prototype.ts
index 61768b7b..6adb3750 100644
--- a/tests/js/anthropic/test_prototype.ts
+++ b/tests/js/anthropic/test_prototype.ts
@@ -147,7 +147,12 @@ async function main() {
     span.setAttribute("gen_ai.provider.name", "anthropic");
     span.setAttribute("gen_ai.request.model", requestModel);
     span.setAttribute("gen_ai.request.max_tokens", requestMaxTokens);
-    span.setAttribute("gen_ai.tool.definitions", JSON.stringify([requestTool]));
+    span.setAttribute("gen_ai.tool.definitions", JSON.stringify([{
+      type: "function",
+      name: requestTool.name,
+      description: requestTool.description,
+      parameters: requestTool.input_schema,
+    }]));
     const resp = await client.messages.create({
       model: requestModel,
       max_tokens: requestMaxTokens,
diff --git a/tests/js/aws-bedrock/test_prototype.ts b/tests/js/aws-bedrock/test_prototype.ts
index e9c598f3..d95bccfa 100644
--- a/tests/js/aws-bedrock/test_prototype.ts
+++ b/tests/js/aws-bedrock/test_prototype.ts
@@ -109,7 +109,12 @@ async function main() {
       },
     };
     const toolConfig = { tools: [toolSpec] };
-    span.setAttribute("gen_ai.tool.definitions", JSON.stringify(toolConfig.tools));
+    span.setAttribute("gen_ai.tool.definitions", JSON.stringify([{
+      type: "function",
+      name: toolSpec.toolSpec.name,
+      description: toolSpec.toolSpec.description,
+      parameters: toolSpec.toolSpec.inputSchema.json,
+    }]));
     const messages = [
       { role: "user" as const, content: [{ text: "What's the weather in Seattle?" }] },
     ];
diff --git a/tests/js/azure-openai/test_prototype.ts b/tests/js/azure-openai/test_prototype.ts
index 507d4daf..96d0428c 100644
--- a/tests/js/azure-openai/test_prototype.ts
+++ b/tests/js/azure-openai/test_prototype.ts
@@ -152,7 +152,12 @@ async function main() {
     span.setAttribute("gen_ai.operation.name", "chat");
     span.setAttribute("gen_ai.provider.name", "openai");
     span.setAttribute("gen_ai.request.model", requestModel);
-    span.setAttribute("gen_ai.tool.definitions", JSON.stringify([requestTool]));
+    span.setAttribute("gen_ai.tool.definitions", JSON.stringify([{
+      type: requestTool.type,
+      name: requestTool.function.name,
+      description: requestTool.function.description,
+      parameters: requestTool.function.parameters,
+    }]));
     span.setAttribute("server.address", endpoint.hostname);
     if (endpoint.port) {
       span.setAttribute("server.port", Number(endpoint.port));
diff --git a/tests/js/cohere/test_prototype.ts b/tests/js/cohere/test_prototype.ts
index 3a08ca8a..c5af1a50 100644
--- a/tests/js/cohere/test_prototype.ts
+++ b/tests/js/cohere/test_prototype.ts
@@ -86,7 +86,18 @@ async function main() {
         location: { description: "City name", type: "str" as const, required: true },
       },
     };
-    span.setAttribute("gen_ai.tool.definitions", JSON.stringify([requestTool]));
+    span.setAttribute("gen_ai.tool.definitions", JSON.stringify([{
+      type: "function",
+      name: requestTool.name,
+      description: requestTool.description,
+      parameters: {
+        type: "object",
+        properties: Object.fromEntries(
+          Object.entries(requestTool.parameterDefinitions).map(([k, v]: [string, any]) => [k, { type: v.type, description: v.description }])
+        ),
+        required: Object.entries(requestTool.parameterDefinitions).filter(([, v]: [string, any]) => v.required).map(([k]) => k),
+      },
+    }]));
     const resp = await client.chat({
       model: requestModel,
       message: "What's the weather in Seattle?",
diff --git a/tests/js/langchain/test_prototype.ts b/tests/js/langchain/test_prototype.ts
index f072cb1f..5f506bca 100644
--- a/tests/js/langchain/test_prototype.ts
+++ b/tests/js/langchain/test_prototype.ts
@@ -129,10 +129,9 @@ async function main() {
         }),
       },
     ];
-    // Derive from the same tools array passed to bindTools (LangChain StructuredToolParams format)
     span.setAttribute(
       "gen_ai.tool.definitions",
-      JSON.stringify(tools.map((t) => ({ name: t.name, description: t.description, schema: toJSONSchema(t.schema) }))),
+      JSON.stringify(tools.map((t) => ({ type: "function", name: t.name, description: t.description, parameters: toJSONSchema(t.schema) }))),
     );
 
     const llmWithTools = llm.bindTools(tools, { tool_choice: "auto" });
diff --git a/tests/js/llamaindex/test_prototype.ts b/tests/js/llamaindex/test_prototype.ts
index c5961336..cfcbf357 100644
--- a/tests/js/llamaindex/test_prototype.ts
+++ b/tests/js/llamaindex/test_prototype.ts
@@ -98,7 +98,12 @@ async function main() {
         },
       },
     };
-    span.setAttribute("gen_ai.tool.definitions", JSON.stringify([requestTool]));
+    span.setAttribute("gen_ai.tool.definitions", JSON.stringify([{
+      type: requestTool.type,
+      name: requestTool.function.name,
+      description: requestTool.function.description,
+      parameters: requestTool.function.parameters,
+    }]));
     const resp = await llm.chat({
       messages: [{ role: "user", content: "What's the weather in Seattle?" }],
       additionalChatOptions: { tools: [requestTool] },
diff --git a/tests/js/openai/test_prototype.ts b/tests/js/openai/test_prototype.ts
index ebc21e2f..1cdf3b0b 100644
--- a/tests/js/openai/test_prototype.ts
+++ b/tests/js/openai/test_prototype.ts
@@ -148,7 +148,12 @@ async function main() {
     span.setAttribute("gen_ai.operation.name", "chat");
     span.setAttribute("gen_ai.provider.name", "openai");
     span.setAttribute("gen_ai.request.model", requestModel);
-    span.setAttribute("gen_ai.tool.definitions", JSON.stringify([requestTool]));
+    span.setAttribute("gen_ai.tool.definitions", JSON.stringify([{
+      type: requestTool.type,
+      name: requestTool.function.name,
+      description: requestTool.function.description,
+      parameters: requestTool.function.parameters,
+    }]));
     span.setAttribute("server.address", endpoint.hostname);
     if (endpoint.port) {
       span.setAttribute("server.port", Number(endpoint.port));
diff --git a/tests/js/vercel-ai/test_prototype.ts b/tests/js/vercel-ai/test_prototype.ts
index cea6eef3..3c8514c2 100644
--- a/tests/js/vercel-ai/test_prototype.ts
+++ b/tests/js/vercel-ai/test_prototype.ts
@@ -146,9 +146,10 @@ async function main() {
       "gen_ai.tool.definitions",
       JSON.stringify(
         Object.entries(tools).map(([name, t]) => ({
+          type: "function",
           name: name,
           description: t.description,
-          inputSchema: toJSONSchema(t.inputSchema!),
+          parameters: toJSONSchema(t.inputSchema!),
         })),
       ),
     );
diff --git a/tests/js/vertexai/test_prototype.ts b/tests/js/vertexai/test_prototype.ts
index d3eaccc5..04f47509 100644
--- a/tests/js/vertexai/test_prototype.ts
+++ b/tests/js/vertexai/test_prototype.ts
@@ -131,7 +131,14 @@ async function main() {
         },
       }],
     };
-    span.setAttribute("gen_ai.tool.definitions", JSON.stringify([requestTool]));
+    span.setAttribute("gen_ai.tool.definitions", JSON.stringify(
+      requestTool.functionDeclarations.map((fn: any) => ({
+        type: "function",
+        name: fn.name,
+        description: fn.description,
+        parameters: fn.parameters,
+      }))
+    ));
     const result = await model.generateContent({
       contents: [{ role: "user", parts: [{ text: "What's the weather in Seattle?" }] }],
       tools: [requestTool],
diff --git a/tests/python/anthropic/test_prototype.py b/tests/python/anthropic/test_prototype.py
index 2270ae5c..b42d0a3c 100644
--- a/tests/python/anthropic/test_prototype.py
+++ b/tests/python/anthropic/test_prototype.py
@@ -114,7 +114,12 @@ def run_chat_tool_call_prototype(client):
         span.set_attribute("gen_ai.operation.name", "chat")
         span.set_attribute("gen_ai.provider.name", "anthropic")
         span.set_attribute("gen_ai.request.model", request_model)
-        span.set_attribute("gen_ai.tool.definitions", json.dumps([request_tool]))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([{
+            "type": "function",
+            "name": request_tool["name"],
+            "description": request_tool["description"],
+            "parameters": request_tool["input_schema"],
+        }]))
         resp = client.messages.create(
             model=request_model,
             max_tokens=100,
diff --git a/tests/python/autogen/test_prototype.py b/tests/python/autogen/test_prototype.py
index bde57f68..08914859 100644
--- a/tests/python/autogen/test_prototype.py
+++ b/tests/python/autogen/test_prototype.py
@@ -101,7 +101,15 @@ def run_chat_tool_call_prototype():
         span.set_attribute("gen_ai.operation.name", "chat")
         span.set_attribute("gen_ai.provider.name", "openai")
         span.set_attribute("gen_ai.request.model", request_model)
-        span.set_attribute("gen_ai.tool.definitions", json.dumps(tools))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([
+            {
+                "type": t["type"],
+                "name": t["function"]["name"],
+                "description": t["function"]["description"],
+                "parameters": t["function"]["parameters"],
+            }
+            for t in tools
+        ]))
         if endpoint.hostname:
             span.set_attribute("server.address", endpoint.hostname)
         if endpoint.port is not None:
diff --git a/tests/python/aws-bedrock/test_prototype.py b/tests/python/aws-bedrock/test_prototype.py
index af7ec004..bb4e2106 100644
--- a/tests/python/aws-bedrock/test_prototype.py
+++ b/tests/python/aws-bedrock/test_prototype.py
@@ -113,7 +113,12 @@ def run_converse_tool_call_prototype(client):
         span.set_attribute("gen_ai.operation.name", "chat")
         span.set_attribute("gen_ai.provider.name", "aws.bedrock")
         span.set_attribute("gen_ai.request.model", request_model)
-        span.set_attribute("gen_ai.tool.definitions", json.dumps(tool_config["tools"]))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([{
+            "type": "function",
+            "name": tool_spec["toolSpec"]["name"],
+            "description": tool_spec["toolSpec"]["description"],
+            "parameters": tool_spec["toolSpec"]["inputSchema"]["json"],
+        }]))
         messages = [
             {
                 "role": "user",
diff --git a/tests/python/azure-ai-foundry/common.py b/tests/python/azure-ai-foundry/common.py
index 2cd3d62e..38ce2e84 100644
--- a/tests/python/azure-ai-foundry/common.py
+++ b/tests/python/azure-ai-foundry/common.py
@@ -84,7 +84,15 @@ def run_invoke_agent(client):
         span.set_attribute("gen_ai.agent.id", agent.id)
         span.set_attribute("gen_ai.agent.name", agent.name or "")
         span.set_attribute("gen_ai.request.model", AGENT_MODEL)
-        span.set_attribute("gen_ai.tool.definitions", json.dumps(tool_defs))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([
+            {
+                "type": t["type"],
+                "name": t["function"]["name"],
+                "description": t["function"]["description"],
+                "parameters": t["function"]["parameters"],
+            }
+            for t in tool_defs
+        ]))
         span.set_attribute("server.address", _SERVER_ADDRESS)
         span.set_attribute("server.port", _SERVER_PORT)
         try:
diff --git a/tests/python/azure-ai-inference/test_prototype.py b/tests/python/azure-ai-inference/test_prototype.py
index 0f19851c..7c3684c5 100644
--- a/tests/python/azure-ai-inference/test_prototype.py
+++ b/tests/python/azure-ai-inference/test_prototype.py
@@ -110,11 +110,9 @@ def run_chat_tool_call_prototype(client):
         span.set_attribute("gen_ai.request.model", request_model)
         span.set_attribute("gen_ai.tool.definitions", json.dumps([{
             "type": "function",
-            "function": {
-                "name": tool.function.name,
-                "description": tool.function.description,
-                "parameters": tool.function.parameters,
-            },
+            "name": tool.function.name,
+            "description": tool.function.description,
+            "parameters": tool.function.parameters,
         }]))
         if endpoint.hostname:
             span.set_attribute("server.address", endpoint.hostname)
diff --git a/tests/python/azure-openai/test_prototype.py b/tests/python/azure-openai/test_prototype.py
index 9882a95f..385ae768 100644
--- a/tests/python/azure-openai/test_prototype.py
+++ b/tests/python/azure-openai/test_prototype.py
@@ -147,7 +147,15 @@ def run_chat_tool_call_prototype(client):
         span.set_attribute("gen_ai.operation.name", "chat")
         span.set_attribute("gen_ai.provider.name", "openai")
         span.set_attribute("gen_ai.request.model", request_model)
-        span.set_attribute("gen_ai.tool.definitions", json.dumps(tools))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([
+            {
+                "type": t["type"],
+                "name": t["function"]["name"],
+                "description": t["function"]["description"],
+                "parameters": t["function"]["parameters"],
+            }
+            for t in tools
+        ]))
         if endpoint.hostname:
             span.set_attribute("server.address", endpoint.hostname)
         if endpoint.port is not None:
diff --git a/tests/python/cohere/test_prototype.py b/tests/python/cohere/test_prototype.py
index 7a4a3122..a6b4bd86 100644
--- a/tests/python/cohere/test_prototype.py
+++ b/tests/python/cohere/test_prototype.py
@@ -98,7 +98,15 @@ def run_chat_tool_call(client):
         span.set_attribute("gen_ai.operation.name", "chat")
         span.set_attribute("gen_ai.provider.name", "cohere")
         span.set_attribute("gen_ai.request.model", request_model)
-        span.set_attribute("gen_ai.tool.definitions", json.dumps(tools))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([
+            {
+                "type": t["type"],
+                "name": t["function"]["name"],
+                "description": t["function"]["description"],
+                "parameters": t["function"]["parameters"],
+            }
+            for t in tools
+        ]))
         resp = client.chat(
             model=request_model,
             messages=[{"role": "user", "content": "What's the weather in Seattle?"}],
diff --git a/tests/python/crewai/test_prototype.py b/tests/python/crewai/test_prototype.py
index bf4c5be6..4ec648cd 100644
--- a/tests/python/crewai/test_prototype.py
+++ b/tests/python/crewai/test_prototype.py
@@ -54,16 +54,12 @@ def get_weather(location: str) -> str:
         span.set_attribute("gen_ai.operation.name", "chat")
         span.set_attribute("gen_ai.provider.name", "openai")
         span.set_attribute("gen_ai.request.model", request_model)
-        # CrewAI converts tools to OpenAI function-calling format before
-        # passing them to litellm, so we mirror that shape here.
         span.set_attribute("gen_ai.tool.definitions", json.dumps([
             {
                 "type": "function",
-                "function": {
-                    "name": t.name,
-                    "description": t.func.__doc__,
-                    "parameters": t.args_schema.model_json_schema(),
-                },
+                "name": t.name,
+                "description": t.func.__doc__,
+                "parameters": t.args_schema.model_json_schema(),
             }
             for t in tools
         ]))
diff --git a/tests/python/dspy/test_prototype.py b/tests/python/dspy/test_prototype.py
index efa3c708..b0088002 100644
--- a/tests/python/dspy/test_prototype.py
+++ b/tests/python/dspy/test_prototype.py
@@ -147,6 +147,7 @@ def run_tool_call():
     dspy.configure(lm=lm)
     messages = [{"role": "user", "content": prompt_text}]
     tool_definition = {
+        "type": "function",
         "name": "get_weather",
         "description": "Get the current weather for a location.",
         "parameters": {
@@ -157,14 +158,18 @@ def run_tool_call():
     }
     request_tool = {
         "type": "function",
-        "function": tool_definition,
+        "function": {
+            "name": tool_definition["name"],
+            "description": tool_definition["description"],
+            "parameters": tool_definition["parameters"],
+        },
     }
 
     with _prototype_tracer.start_as_current_span("chat gpt-4o-mini") as span:
         span.set_attribute("gen_ai.operation.name", "chat")
         span.set_attribute("gen_ai.provider.name", "openai")
         span.set_attribute("gen_ai.request.model", request_model)
-        span.set_attribute("gen_ai.tool.definitions", json.dumps([request_tool]))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([tool_definition]))
         result = lm(
             messages=messages,
             tools=[request_tool],
diff --git a/tests/python/google-adk/test_prototype.py b/tests/python/google-adk/test_prototype.py
index 3b2e02d4..ddf976c9 100644
--- a/tests/python/google-adk/test_prototype.py
+++ b/tests/python/google-adk/test_prototype.py
@@ -121,7 +121,15 @@ async def _run():
                 span.set_attribute("gen_ai.provider.name", "google_genai")
                 span.set_attribute("gen_ai.conversation.id", session.id)
                 span.set_attribute("gen_ai.request.model", request_model)
-                span.set_attribute("gen_ai.tool.definitions", json.dumps(tool_defs))
+                span.set_attribute("gen_ai.tool.definitions", json.dumps([
+                    {
+                        "type": "function",
+                        "name": t["name"],
+                        "description": t["description"],
+                        "parameters": t["parameters"],
+                    }
+                    for t in tool_defs
+                ]))
                 usage_metadata = None
                 finish_reason = None
                 try:
diff --git a/tests/python/google-genai/test_prototype.py b/tests/python/google-genai/test_prototype.py
index 1b1deda3..16b18ddc 100644
--- a/tests/python/google-genai/test_prototype.py
+++ b/tests/python/google-genai/test_prototype.py
@@ -115,17 +115,16 @@ def run_chat_tool_call():
         span.set_attribute("gen_ai.provider.name", "google_genai")
         span.set_attribute("gen_ai.request.model", request_model)
         span.set_attribute("gen_ai.tool.definitions", json.dumps([{
-            "function_declarations": [{
-                "name": "get_weather",
-                "description": "Get the current weather",
-                "parameters": {
-                    "type": "object",
-                    "properties": {
-                        "location": {"type": "string", "description": "City name"},
-                    },
-                    "required": ["location"],
+            "type": "function",
+            "name": "get_weather",
+            "description": "Get the current weather",
+            "parameters": {
+                "type": "object",
+                "properties": {
+                    "location": {"type": "string", "description": "City name"},
                 },
-            }]
+                "required": ["location"],
+            },
         }]))
         response = client.models.generate_content(
             model=request_model,
diff --git a/tests/python/groq/test_prototype.py b/tests/python/groq/test_prototype.py
index 4e67633a..496dbdbe 100644
--- a/tests/python/groq/test_prototype.py
+++ b/tests/python/groq/test_prototype.py
@@ -121,7 +121,15 @@ def run_chat_tool_call_prototype(client):
         span.set_attribute("gen_ai.operation.name", "chat")
         span.set_attribute("gen_ai.provider.name", "groq")
         span.set_attribute("gen_ai.request.model", request_model)
-        span.set_attribute("gen_ai.tool.definitions", json.dumps(tools))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([
+            {
+                "type": t["type"],
+                "name": t["function"]["name"],
+                "description": t["function"]["description"],
+                "parameters": t["function"]["parameters"],
+            }
+            for t in tools
+        ]))
         resp = client.chat.completions.create(
             model=request_model,
             messages=[{"role": "user", "content": "What's the weather in Seattle?"}],
diff --git a/tests/python/haystack/test_prototype.py b/tests/python/haystack/test_prototype.py
index c9d5811a..d90e2bef 100644
--- a/tests/python/haystack/test_prototype.py
+++ b/tests/python/haystack/test_prototype.py
@@ -119,6 +119,7 @@ def get_weather(location: str) -> str:
         },
     )
     tool_definition = {
+        "type": "function",
         "name": weather_tool.name,
         "description": weather_tool.description,
         "parameters": weather_tool.parameters,
diff --git a/tests/python/instructor/test_prototype.py b/tests/python/instructor/test_prototype.py
index dcf2c3f0..9a5fe069 100644
--- a/tests/python/instructor/test_prototype.py
+++ b/tests/python/instructor/test_prototype.py
@@ -101,7 +101,15 @@ class WeatherRequest(BaseModel):
         span.set_attribute("gen_ai.operation.name", "chat")
         span.set_attribute("gen_ai.provider.name", "openai")
         span.set_attribute("gen_ai.request.model", request_model)
-        span.set_attribute("gen_ai.tool.definitions", json.dumps(tools))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([
+            {
+                "type": t["type"],
+                "name": t["function"]["name"],
+                "description": t["function"]["description"],
+                "parameters": t["function"]["parameters"],
+            }
+            for t in tools
+        ]))
         resp, completion = client.chat.completions.create_with_completion(
             model=request_model,
             messages=[{"role": "user", "content": "What's the weather in Seattle?"}],
diff --git a/tests/python/langchain/test_prototype.py b/tests/python/langchain/test_prototype.py
index 4b0a31cb..123e1d41 100644
--- a/tests/python/langchain/test_prototype.py
+++ b/tests/python/langchain/test_prototype.py
@@ -120,9 +120,10 @@ def get_weather(location: str) -> str:
         return "Sunny, 72°F"
 
     tool_definition = {
+        "type": "function",
         "name": get_weather.name,
         "description": get_weather.description,
-        "args_schema": get_weather.args_schema.model_json_schema(),
+        "parameters": get_weather.args_schema.model_json_schema(),
     }
 
     with _prototype_tracer.start_as_current_span("chat gpt-4o-mini") as span:
diff --git a/tests/python/litellm/test_prototype.py b/tests/python/litellm/test_prototype.py
index 5a02684c..8de9ca6c 100644
--- a/tests/python/litellm/test_prototype.py
+++ b/tests/python/litellm/test_prototype.py
@@ -171,7 +171,12 @@ def run_chat_tool_call():
         span.set_attribute("gen_ai.operation.name", "chat")
         span.set_attribute("gen_ai.provider.name", "openai")
         span.set_attribute("gen_ai.request.model", request_model)
-        span.set_attribute("gen_ai.tool.definitions", json.dumps([request_tool]))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([{
+            "type": request_tool["type"],
+            "name": request_tool["function"]["name"],
+            "description": request_tool["function"]["description"],
+            "parameters": request_tool["function"]["parameters"],
+        }]))
         span.set_attribute(
             "gen_ai.input.messages",
             json.dumps([
diff --git a/tests/python/llamaindex/test_prototype.py b/tests/python/llamaindex/test_prototype.py
index 47e5d665..28c697de 100644
--- a/tests/python/llamaindex/test_prototype.py
+++ b/tests/python/llamaindex/test_prototype.py
@@ -107,9 +107,10 @@ def get_weather(location: str) -> str:
 
     weather_tool = FunctionTool.from_defaults(fn=get_weather)
     tool_definition = {
+        "type": "function",
         "name": weather_tool.metadata.name,
         "description": weather_tool.metadata.description,
-        "fn_schema": weather_tool.metadata.fn_schema.model_json_schema(),
+        "parameters": weather_tool.metadata.fn_schema.model_json_schema(),
     }
     with _prototype_tracer.start_as_current_span("chat gpt-4o-mini") as span:
         span.set_attribute("gen_ai.operation.name", "chat")
diff --git a/tests/python/mistralai/test_prototype.py b/tests/python/mistralai/test_prototype.py
index 0c5ceb97..af73c662 100644
--- a/tests/python/mistralai/test_prototype.py
+++ b/tests/python/mistralai/test_prototype.py
@@ -98,7 +98,15 @@ def run_chat_tool_call(client):
         span.set_attribute("gen_ai.operation.name", "chat")
         span.set_attribute("gen_ai.provider.name", "mistral")
         span.set_attribute("gen_ai.request.model", request_model)
-        span.set_attribute("gen_ai.tool.definitions", json.dumps(tools))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([
+            {
+                "type": t["type"],
+                "name": t["function"]["name"],
+                "description": t["function"]["description"],
+                "parameters": t["function"]["parameters"],
+            }
+            for t in tools
+        ]))
         resp = client.chat.complete(
             model=request_model,
             messages=[{"role": "user", "content": "What's the weather in Seattle?"}],
diff --git a/tests/python/openai-agents/test_prototype.py b/tests/python/openai-agents/test_prototype.py
index 4d2abb0e..3dee469b 100644
--- a/tests/python/openai-agents/test_prototype.py
+++ b/tests/python/openai-agents/test_prototype.py
@@ -48,16 +48,12 @@ def get_weather(location: str) -> str:
         span.set_attribute("gen_ai.provider.name", "openai")
         span.set_attribute("gen_ai.request.model", request_model)
         span.set_attribute("gen_ai.response.model", request_model)
-        # OpenAI Agents SDK converts FunctionTools to OpenAI function-calling
-        # format before sending to the API, so we mirror that shape here.
         span.set_attribute("gen_ai.tool.definitions", json.dumps([
             {
                 "type": "function",
-                "function": {
-                    "name": t.name,
-                    "description": t.description,
-                    "parameters": t.params_json_schema,
-                },
+                "name": t.name,
+                "description": t.description,
+                "parameters": t.params_json_schema,
             }
             for t in tools
             if isinstance(t, FunctionTool)
diff --git a/tests/python/openai-assistants/common.py b/tests/python/openai-assistants/common.py
index 2daf3fda..9e359192 100644
--- a/tests/python/openai-assistants/common.py
+++ b/tests/python/openai-assistants/common.py
@@ -78,7 +78,15 @@ def run_invoke_agent(client):
         span.set_attribute("gen_ai.agent.id", assistant.id)
         span.set_attribute("gen_ai.agent.name", assistant.name or "")
         span.set_attribute("gen_ai.request.model", "gpt-4o-mini")
-        span.set_attribute("gen_ai.tool.definitions", json.dumps(tool_defs))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([
+            {
+                "type": t["type"],
+                "name": t["function"]["name"],
+                "description": t["function"]["description"],
+                "parameters": t["function"]["parameters"],
+            }
+            for t in tool_defs
+        ]))
         span.set_attribute("server.address", _SERVER_ADDRESS)
         span.set_attribute("server.port", _SERVER_PORT)
         try:
diff --git a/tests/python/openai/test_prototype.py b/tests/python/openai/test_prototype.py
index e7be94b5..7bc5bea3 100644
--- a/tests/python/openai/test_prototype.py
+++ b/tests/python/openai/test_prototype.py
@@ -147,7 +147,15 @@ def run_chat_tool_call_prototype(client):
         span.set_attribute("gen_ai.operation.name", "chat")
         span.set_attribute("gen_ai.provider.name", "openai")
         span.set_attribute("gen_ai.request.model", request_model)
-        span.set_attribute("gen_ai.tool.definitions", json.dumps(tools))
+        span.set_attribute("gen_ai.tool.definitions", json.dumps([
+            {
+                "type": t["type"],
+                "name": t["function"]["name"],
+                "description": t["function"]["description"],
+                "parameters": t["function"]["parameters"],
+            }
+            for t in tools
+        ]))
         if endpoint.hostname:
             span.set_attribute("server.address", endpoint.hostname)
         if endpoint.port is not None:
diff --git a/tests/python/pydantic-ai/test_prototype.py b/tests/python/pydantic-ai/test_prototype.py
index 63602f69..8db43a34 100644
--- a/tests/python/pydantic-ai/test_prototype.py
+++ b/tests/python/pydantic-ai/test_prototype.py
@@ -155,16 +155,12 @@ def get_weather(location: str) -> str:
                 {"role": "user", "parts": [{"type": "text", "content": prompt_text}]},
             ]),
         )
-        # Pydantic AI converts tools to OpenAI function-calling format before
-        # sending to the API, so we mirror that shape here.
         span.set_attribute("gen_ai.tool.definitions", json.dumps([
             {
                 "type": "function",
-                "function": {
-                    "name": t.name,
-                    "description": t.description,
-                    "parameters": t.function_schema.json_schema,
-                },
+                "name": t.name,
+                "description": t.description,
+                "parameters": t.function_schema.json_schema,
             }
             for t in tools
         ]))
diff --git a/tests/python/vertexai/test_prototype.py b/tests/python/vertexai/test_prototype.py
index 47cbd8e6..2248fe1b 100644
--- a/tests/python/vertexai/test_prototype.py
+++ b/tests/python/vertexai/test_prototype.py
@@ -136,17 +136,16 @@ def run_chat_tool_call():
         span.set_attribute("gen_ai.provider.name", "vertex_ai")
         span.set_attribute("gen_ai.request.model", request_model)
         span.set_attribute("gen_ai.tool.definitions", json.dumps([{
-            "function_declarations": [{
-                "name": "get_weather",
-                "description": "Get the current weather",
-                "parameters": {
-                    "type": "object",
-                    "properties": {
-                        "location": {"type": "string", "description": "City name"},
-                    },
-                    "required": ["location"],
+            "type": "function",
+            "name": "get_weather",
+            "description": "Get the current weather",
+            "parameters": {
+                "type": "object",
+                "properties": {
+                    "location": {"type": "string", "description": "City name"},
                 },
-            }]
+                "required": ["location"],
+            },
         }]))
         with warnings.catch_warnings():
             warnings.simplefilter("ignore", DeprecationWarning)