fix: properly check that only the last message is kept when doing multi-turn conversations

src/runner/templates/agents/node/manual/template.njk

@@ -45,46 +45,50 @@ function trimMessages(messages, maxSize = 10000) {
 }
 
 function buildSentryMessages(messages) {
-  const sentryMessages = [];
-  const legacyMessages = [];
   let systemInstructions = null;
 
   for (const msg of messages) {
-    const { role, content } = msg;
-
-    if (role === "system") {
-      systemInstructions = typeof content === "string" ? content : JSON.stringify(content);
+    if (msg.role === "system") {
+      systemInstructions =
+        typeof msg.content === "string" ? msg.content : JSON.stringify(msg.content);
     }
+  }
 
-    const parts = [];
-    if (typeof content === "string") {
-      parts.push({ type: "text", text: content });
-    } else if (Array.isArray(content)) {
-      for (const part of content) {
-        if (part.type === "text") {
-          parts.push({ type: "text", text: part.text });
-        } else if (part.type === "image") {
-          parts.push({ type: "text", text: "[Blob substitute]" });
-        }
-      }
-    }
+  const lastMessage = messages[messages.length - 1];
+  if (!lastMessage) {
+    return { sentryMessages: [], legacyMessages: [], systemInstructions };
+  }
 
-    sentryMessages.push({
-      role,
-      content: typeof content === "string" ? content : "[multimodal]",
-      parts,
-    });
-
-    if (Array.isArray(content)) {
-      const redacted = content.map((part) =>
-        part.type === "image" ? { type: "text", text: "[Blob substitute]" } : part
-      );
-      legacyMessages.push({ role, content: redacted });
-    } else {
-      legacyMessages.push({ role, content });
+  const { role, content } = lastMessage;
+
+  const parts = [];
+  if (typeof content === "string") {
+    parts.push({ type: "text", text: content });
+  } else if (Array.isArray(content)) {
+    for (const part of content) {
+      if (part.type === "text") {
+        parts.push({ type: "text", text: part.text });
+      } else if (part.type === "image") {
+        parts.push({ type: "text", text: "[Blob substitute]" });
+      }
     }
   }
 
+  const sentryMessages = [{
+    role,
+    content: typeof content === "string" ? content : "[multimodal]",
+    parts,
+  }];
+
+  const legacyMessages = [Array.isArray(content)
+    ? {
+        role,
+        content: content.map((part) =>
+          part.type === "image" ? { type: "text", text: "[Blob substitute]" } : part,
+        ),
+      }
+    : { role, content }];
+
   return { sentryMessages, legacyMessages, systemInstructions };
 }
 
@@ -150,6 +154,10 @@ const TOOLS = {{ agent.tools | dump }};
         agentSpan.setAttribute("gen_ai.usage.output_tokens", outputTokens{{ loop.index }});
         agentSpan.setAttribute("gen_ai.usage.output_tokens.reasoning", Math.max(0, Math.floor(outputTokens{{ loop.index }} / 4)));
         agentSpan.setAttribute("gen_ai.usage.total_tokens", totalTokens{{ loop.index }});
+        agentSpan.setAttribute("gen_ai.input.messages", otelJson{{ loop.index }});
+        if (system{{ loop.index }} !== null) {
+          agentSpan.setAttribute("gen_ai.system_instructions", system{{ loop.index }});
+        }
 
         // Chat span (child of agent)
         const chatDesc{{ loop.index }} = `chat ${model{{ loop.index }}}`;

src/runner/templates/agents/python/manual/template.njk

@@ -48,46 +48,47 @@ def trim_messages(messages, max_size=10000):
 
 
 def build_sentry_messages(messages):
-    """Build gen_ai.input.messages and gen_ai.request.messages from raw messages."""
-    sentry_messages = []
-    legacy_messages = []
+    """Build gen_ai.input.messages and gen_ai.request.messages from the last raw message."""
     system_instructions = None
 
     for msg in messages:
-        role = msg["role"]
         content = msg.get("content", "")
-
-        if role == "system":
+        if msg["role"] == "system":
             system_instructions = content if isinstance(content, str) else json.dumps(content)
 
-        # New OTel format with parts
-        parts = []
-        if isinstance(content, str):
-            parts.append({"type": "text", "text": content})
-        elif isinstance(content, list):
-            for part in content:
-                if part.get("type") == "text":
-                    parts.append({"type": "text", "text": part["text"]})
-                elif part.get("type") == "image":
-                    parts.append({"type": "text", "text": "[Blob substitute]"})
-
-        sentry_messages.append({
-            "role": role,
-            "content": content if isinstance(content, str) else "[multimodal]",
-            "parts": parts,
-        })
-
-        # Legacy format with binary redaction
-        if isinstance(content, list):
-            redacted = []
-            for part in content:
-                if part.get("type") == "text":
-                    redacted.append(part)
-                elif part.get("type") == "image":
-                    redacted.append({"type": "text", "text": "[Blob substitute]"})
-            legacy_messages.append({"role": role, "content": redacted})
-        else:
-            legacy_messages.append({"role": role, "content": content})
+    if not messages:
+        return [], [], system_instructions
+
+    last_message = messages[-1]
+    role = last_message["role"]
+    content = last_message.get("content", "")
+
+    parts = []
+    if isinstance(content, str):
+        parts.append({"type": "text", "text": content})
+    elif isinstance(content, list):
+        for part in content:
+            if part.get("type") == "text":
+                parts.append({"type": "text", "text": part["text"]})
+            elif part.get("type") == "image":
+                parts.append({"type": "text", "text": "[Blob substitute]"})
+
+    sentry_messages = [{
+        "role": role,
+        "content": content if isinstance(content, str) else "[multimodal]",
+        "parts": parts,
+    }]
+
+    if isinstance(content, list):
+        redacted = []
+        for part in content:
+            if part.get("type") == "text":
+                redacted.append(part)
+            elif part.get("type") == "image":
+                redacted.append({"type": "text", "text": "[Blob substitute]"})
+        legacy_messages = [{"role": role, "content": redacted}]
+    else:
+        legacy_messages = [{"role": role, "content": content}]
 
     return sentry_messages, legacy_messages, system_instructions
 
@@ -151,6 +152,9 @@ TOOLS = {{ agent.tools | dump }}
         agent_span.set_data("gen_ai.usage.output_tokens", output_tokens)
         agent_span.set_data("gen_ai.usage.output_tokens.reasoning", max(0, output_tokens // 4))
         agent_span.set_data("gen_ai.usage.total_tokens", total_tokens)
+        agent_span.set_data("gen_ai.input.messages", otel_messages_json)
+        if system_instructions is not None:
+            agent_span.set_data("gen_ai.system_instructions", system_instructions)
 
         # Chat span (child of agent)
         chat_desc = f"chat {model}"

src/runner/templates/llm/node/manual/template.njk

@@ -45,48 +45,50 @@ function trimMessages(messages, maxSize = 10000) {
 }
 
 function buildSentryMessages(messages) {
-  const sentryMessages = [];
-  const legacyMessages = [];
   let systemInstructions = null;
 
   for (const msg of messages) {
-    const { role, content } = msg;
-
-    if (role === "system") {
-      systemInstructions = typeof content === "string" ? content : JSON.stringify(content);
+    if (msg.role === "system") {
+      systemInstructions =
+        typeof msg.content === "string" ? msg.content : JSON.stringify(msg.content);
     }
+  }
 
-    // New OTel format with parts
-    const parts = [];
-    if (typeof content === "string") {
-      parts.push({ type: "text", text: content });
-    } else if (Array.isArray(content)) {
-      for (const part of content) {
-        if (part.type === "text") {
-          parts.push({ type: "text", text: part.text });
-        } else if (part.type === "image") {
-          parts.push({ type: "text", text: "[Blob substitute]" });
-        }
-      }
-    }
+  const lastMessage = messages[messages.length - 1];
+  if (!lastMessage) {
+    return { sentryMessages: [], legacyMessages: [], systemInstructions };
+  }
 
-    sentryMessages.push({
-      role,
-      content: typeof content === "string" ? content : "[multimodal]",
-      parts,
-    });
-
-    // Legacy format with binary redaction
-    if (Array.isArray(content)) {
-      const redacted = content.map((part) =>
-        part.type === "image" ? { type: "text", text: "[Blob substitute]" } : part
-      );
-      legacyMessages.push({ role, content: redacted });
-    } else {
-      legacyMessages.push({ role, content });
+  const { role, content } = lastMessage;
+
+  const parts = [];
+  if (typeof content === "string") {
+    parts.push({ type: "text", text: content });
+  } else if (Array.isArray(content)) {
+    for (const part of content) {
+      if (part.type === "text") {
+        parts.push({ type: "text", text: part.text });
+      } else if (part.type === "image") {
+        parts.push({ type: "text", text: "[Blob substitute]" });
+      }
     }
   }
 
+  const sentryMessages = [{
+    role,
+    content: typeof content === "string" ? content : "[multimodal]",
+    parts,
+  }];
+
+  const legacyMessages = [Array.isArray(content)
+    ? {
+        role,
+        content: content.map((part) =>
+          part.type === "image" ? { type: "text", text: "[Blob substitute]" } : part,
+        ),
+      }
+    : { role, content }];
+
   return { sentryMessages, legacyMessages, systemInstructions };
 }
 {% endblock %}

src/runner/templates/llm/python/manual/template.njk

@@ -44,46 +44,47 @@ def trim_messages(messages, max_size=10000):
 
 
 def build_sentry_messages(messages):
-    """Build gen_ai.input.messages and gen_ai.request.messages from raw messages."""
-    sentry_messages = []
-    legacy_messages = []
+    """Build gen_ai.input.messages and gen_ai.request.messages from the last raw message."""
     system_instructions = None
 
     for msg in messages:
-        role = msg["role"]
         content = msg.get("content", "")
-
-        if role == "system":
+        if msg["role"] == "system":
             system_instructions = content if isinstance(content, str) else json.dumps(content)
 
-        # New OTel format with parts
-        parts = []
-        if isinstance(content, str):
-            parts.append({"type": "text", "text": content})
-        elif isinstance(content, list):
-            for part in content:
-                if part.get("type") == "text":
-                    parts.append({"type": "text", "text": part["text"]})
-                elif part.get("type") == "image":
-                    parts.append({"type": "text", "text": "[Blob substitute]"})
-
-        sentry_messages.append({
-            "role": role,
-            "content": content if isinstance(content, str) else "[multimodal]",
-            "parts": parts,
-        })
-
-        # Legacy format with binary redaction
-        if isinstance(content, list):
-            redacted = []
-            for part in content:
-                if part.get("type") == "text":
-                    redacted.append(part)
-                elif part.get("type") == "image":
-                    redacted.append({"type": "text", "text": "[Blob substitute]"})
-            legacy_messages.append({"role": role, "content": redacted})
-        else:
-            legacy_messages.append({"role": role, "content": content})
+    if not messages:
+        return [], [], system_instructions
+
+    last_message = messages[-1]
+    role = last_message["role"]
+    content = last_message.get("content", "")
+
+    parts = []
+    if isinstance(content, str):
+        parts.append({"type": "text", "text": content})
+    elif isinstance(content, list):
+        for part in content:
+            if part.get("type") == "text":
+                parts.append({"type": "text", "text": part["text"]})
+            elif part.get("type") == "image":
+                parts.append({"type": "text", "text": "[Blob substitute]"})
+
+    sentry_messages = [{
+        "role": role,
+        "content": content if isinstance(content, str) else "[multimodal]",
+        "parts": parts,
+    }]
+
+    if isinstance(content, list):
+        redacted = []
+        for part in content:
+            if part.get("type") == "text":
+                redacted.append(part)
+            elif part.get("type") == "image":
+                redacted.append({"type": "text", "text": "[Blob substitute]"})
+        legacy_messages = [{"role": role, "content": redacted}]
+    else:
+        legacy_messages = [{"role": role, "content": content}]
 
     return sentry_messages, legacy_messages, system_instructions
 {% endblock %}