end

open-sse/translator/request/antigravity-to-openai.js

@@ -138,12 +138,14 @@ function convertContent(content) {
 
     // Text with thoughtSignature = regular text after thinking
     if (part.thoughtSignature && part.text !== undefined) {
-      textParts.push({ type: OPENAI_BLOCK.TEXT, text: part.text });
+      if (part.text) {
+        textParts.push({ type: OPENAI_BLOCK.TEXT, text: part.text });
+      }
       continue;
     }
 
     // Regular text
-    if (part.text !== undefined) {
+    if (part.text !== undefined && part.text !== "") {
       textParts.push({ type: OPENAI_BLOCK.TEXT, text: part.text });
     }
 
@@ -180,8 +182,22 @@ function convertContent(content) {
     }
   }
 
-  // Content with only functionResponses → return array of tool messages
+  // Content with functionResponses — return array of tool result messages,
+  // plus an assistant message for any co-located tool calls / text.
   if (toolResults.length > 0) {
+    if (toolCalls.length > 0 || textParts.length > 0 || reasoningContent) {
+      const assistantMsg = { role: ROLE.ASSISTANT };
+      if (textParts.length > 0) {
+        assistantMsg.content = collapseTextParts(textParts);
+      }
+      if (reasoningContent) {
+        assistantMsg.reasoning_content = reasoningContent;
+      }
+      if (toolCalls.length > 0) {
+        assistantMsg.tool_calls = toolCalls;
+      }
+      return [...toolResults, assistantMsg];
+    }
     return toolResults;
   }
 

open-sse/translator/request/claude-to-kiro.js

@@ -393,9 +393,12 @@ export function claudeToKiroRequest(model, body, stream, credentials) {
     reconcileOrphanedToolResults(history, currentMessage);
   }
 
-  // API-key auth must never use the shared default ARN (403); OAuth/social fall back to it.
+  // api_key / idc / external_idp must never use the shared default ARN (belongs
+  // to another account → 403 "bearer token invalid"); OAuth/social fall back to it.
   const authMethod = credentials?.providerSpecificData?.authMethod;
-  const profileArn = authMethod === "api_key"
+  const accountBoundAuth =
+    authMethod === "api_key" || authMethod === "idc" || authMethod === "external_idp";
+  const profileArn = accountBoundAuth
     ? (credentials?.providerSpecificData?.profileArn || "")
     : (credentials?.providerSpecificData?.profileArn || resolveDefaultProfileArn(authMethod));
 

open-sse/translator/request/claude-to-openai.js

@@ -129,8 +129,24 @@ function fixMissingToolResponsesOpenAI(messages) {
   }
 }
 
+// Wrap mid-conversation system text so it ends as a user turn (avoids Anthropic prefill 400)
+function systemReminderText(content) {
+  const parts = Array.isArray(content)
+    ? content.filter(c => c?.type === CLAUDE_BLOCK.TEXT).map(c => c.text || "")
+    : [typeof content === "string" ? content : ""];
+  const text = parts.filter(Boolean).join("\n");
+  if (!text.trim()) return "";
+  return `<system-reminder>\n${text}\n</system-reminder>`;
+}
+
 // Convert single Claude message - returns single message or array of messages
 function convertClaudeMessage(msg) {
+  // Mid-conversation system message -> user (per Anthropic placement rules)
+  if (msg.role === ROLE.SYSTEM) {
+    const text = systemReminderText(msg.content);
+    return text ? { role: ROLE.USER, content: text } : null;
+  }
+
   const role = msg.role === ROLE.USER || msg.role === ROLE.TOOL ? ROLE.USER : ROLE.ASSISTANT;
   
   // Simple string content

open-sse/translator/request/openai-to-gemini.js

@@ -35,6 +35,17 @@ function sanitizeGeminiFunctionName(name) {
   return sanitized.substring(0, 64);
 }
 
+function normalizeGeminiContents(contents) {
+  const out = [];
+  for (const c of contents || []) {
+    if (!c?.role || !Array.isArray(c.parts) || c.parts.length === 0) continue;
+    const last = out.at(-1);
+    if (last?.role === c.role) last.parts.push(...c.parts);
+    else out.push({ ...c, parts: [...c.parts] });
+  }
+  return out;
+}
+
 // Core: Convert OpenAI request to Gemini format (base for all variants)
 function openaiToGeminiBase(model, body, stream, signature = DEFAULT_THINKING_AG_SIGNATURE) {
   const result = {
@@ -217,6 +228,7 @@ function openaiToGeminiBase(model, body, stream, signature = DEFAULT_THINKING_AG
     }
   }
 
+  result.contents = normalizeGeminiContents(result.contents);
   return result;
 }
 
@@ -299,7 +311,7 @@ function wrapInCloudCodeEnvelope(model, geminiCLI, credentials = null, isAntigra
 }
 
 // Wrap Claude format in Cloud Code envelope for Antigravity
-function wrapInCloudCodeEnvelopeForClaude(model, claudeRequest, credentials = null) {
+function wrapInCloudCodeEnvelopeForClaude(model, claudeRequest, credentials = null, signature = DEFAULT_THINKING_AG_SIGNATURE) {
   const projectId = credentials?.projectId || generateProjectId();
 
   const envelope = {
@@ -343,6 +355,7 @@ function wrapInCloudCodeEnvelopeForClaude(model, claudeRequest, credentials = nu
             parts.push({ text: block.text });
           } else if (block.type === CLAUDE_BLOCK.TOOL_USE) {
             parts.push({
+              thoughtSignature: signature,
               functionCall: {
                 id: block.id,
                 name: sanitizeGeminiFunctionName(block.name),
@@ -425,6 +438,7 @@ function wrapInCloudCodeEnvelopeForClaude(model, claudeRequest, credentials = nu
     envelope.request.systemInstruction = { role: GEMINI_ROLE.USER, parts: systemParts };
   }
 
+  envelope.request.contents = normalizeGeminiContents(envelope.request.contents);
   return envelope;
 }
 

open-sse/translator/request/openai-to-kiro.js

@@ -530,8 +530,15 @@ export function openaiToKiroRequest(model, body, stream, credentials) {
   // (the ARN doesn't belong to the key's account). So for api_key, only send a
   // profileArn that was actually resolved for this connection — never the default.
   // OAuth/social keep the default fallback (their tokens accept it).
+  // api_key / idc / external_idp carry an account-specific (or token-bound)
+  // profile. The shared builder-id/social default ARN belongs to a different
+  // account and triggers 403 "bearer token invalid", so never fall back to it —
+  // send the resolved ARN, or an empty string so CodeWhisperer uses the token's
+  // own default profile. Only OAuth/social keep the shared placeholder.
   const authMethod = credentials?.providerSpecificData?.authMethod;
-  const profileArn = authMethod === "api_key"
+  const accountBoundAuth =
+    authMethod === "api_key" || authMethod === "idc" || authMethod === "external_idp";
+  const profileArn = accountBoundAuth
     ? (credentials?.providerSpecificData?.profileArn || "")
     : (credentials?.providerSpecificData?.profileArn || resolveDefaultProfileArn(authMethod));