fix: strip thinking blocks when converting messages, causing DeepSeek 400 errors on follow-up requests

Author: codex-mohan

.changeset/patch-thinking-echo-back.md

@@ -0,0 +1,5 @@
+---
+"@mohanscodex/spectra-ai": patch
+---
+
+Fix thinking/reasoning blocks being stripped when sending follow-up API requests to providers that require reasoning_content echo-back (DeepSeek, Qwen, etc.)

.gitignore

@@ -46,8 +46,13 @@ coverage/
 # Temporary
 *.tmp
 *.temp
+*.diff
 .tmp/
 
+# Analysis scratch files (root-level scripts for one-off debugging)
+trace_detail.py
+trace_query.py
+
 # Planning (local only)
 .planning/
 

packages/ai/src/providers/openai-completions.ts

@@ -320,13 +320,18 @@ function convertMessages(model: Model, context: Context): ChatCompletionMessageP
       }
     } else if (msg.role === "assistant") {
       const textBlocks = msg.content.filter((b) => b.type === "text") as TextContent[];
+      const thinkingBlocks = msg.content.filter((b) => b.type === "thinking" && !(b as ThinkingContent).redacted) as ThinkingContent[];
       const toolCalls = msg.content.filter((b) => b.type === "toolCall") as ToolCall[];
 
-      if (textBlocks.length > 0 || toolCalls.length > 0) {
-        const assistantMsg: ChatCompletionAssistantMessageParam = {
-          role: "assistant",
-          content: textBlocks.map((b) => sanitizeSurrogates(b.text)).join(""),
-        };
+      if (textBlocks.length > 0 || thinkingBlocks.length > 0 || toolCalls.length > 0) {
+        const assistantMsg = {
+          role: "assistant" as const,
+          content: textBlocks.map((b) => sanitizeSurrogates(b.text)).join("") || null,
+        } as Record<string, unknown>;
+
+        if (thinkingBlocks.length > 0) {
+          assistantMsg.reasoning_content = thinkingBlocks.map((t) => t.thinking).join("\n");
+        }
 
         if (toolCalls.length > 0) {
           assistantMsg.tool_calls = toolCalls.map((tc) => ({
@@ -336,7 +341,7 @@ function convertMessages(model: Model, context: Context): ChatCompletionMessageP
           }));
         }
 
-        params.push(assistantMsg);
+        params.push(assistantMsg as unknown as ChatCompletionAssistantMessageParam);
       }
     } else if (msg.role === "toolResult") {
       const textResult = msg.content

packages/ai/src/providers/openai-responses.ts

@@ -321,12 +321,19 @@ function convertResponsesMessages(model: Model, context: Context): unknown[] {
         messages.push({ role: "user", content });
       }
     } else if (msg.role === "assistant") {
+      const textBlocks = msg.content.filter((b) => b.type === "text") as TextContent[];
+      if (textBlocks.length > 0) {
+        messages.push({
+          type: "message",
+          role: "assistant",
+          content: textBlocks.map((b) => ({ type: "output_text" as const, text: sanitizeSurrogates(b.text) })),
+        });
+      }
       for (const block of msg.content) {
-        if (block.type === "text") {
+        if (block.type === "thinking" && !(block as ThinkingContent).redacted) {
           messages.push({
-            type: "message",
-            role: "assistant",
-            content: [{ type: "output_text", text: sanitizeSurrogates((block as TextContent).text) }],
+            type: "reasoning",
+            summary: [{ type: "summary_text" as const, text: (block as ThinkingContent).thinking }],
           });
         } else if (block.type === "toolCall") {
           const tc = block as ToolCall;