From 11d2f3e5f8751cbdca35139cd7310ce0cdb7bad2 Mon Sep 17 00:00:00 2001
From: Dax Raad <d@ironbay.co>
Date: Fri, 26 Jun 2026 13:55:04 -0400
Subject: [PATCH] fix(llm): end reasoning before responses

---
 packages/llm/src/protocols/gemini.ts          | 32 +++++++++++++------
 packages/llm/src/protocols/openai-chat.ts     |  7 +++-
 packages/llm/test/provider/gemini.test.ts     |  5 ++-
 .../llm/test/provider/openai-chat.test.ts     |  2 +-
 4 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/packages/llm/src/protocols/gemini.ts b/packages/llm/src/protocols/gemini.ts
index 3a2311c8fd..c732460820 100644
--- a/packages/llm/src/protocols/gemini.ts
+++ b/packages/llm/src/protocols/gemini.ts
@@ -407,21 +407,35 @@ const step = (state: ParserState, event: GeminiEvent) => {
     if ("thoughtSignature" in part && part.thoughtSignature && "thought" in part && part.thought)
       reasoningSignature = part.thoughtSignature
     if ("text" in part && part.text.length > 0) {
-      lifecycle = part.thought
-        ? Lifecycle.reasoningDelta(
-            lifecycle,
-            events,
-            "reasoning-0",
-            part.text,
-            part.thoughtSignature ? googleMetadata({ thoughtSignature: part.thoughtSignature }) : undefined,
-          )
-        : Lifecycle.textDelta(lifecycle, events, "text-0", part.text)
+      if (part.thought) {
+        lifecycle = Lifecycle.reasoningDelta(
+          lifecycle,
+          events,
+          "reasoning-0",
+          part.text,
+          part.thoughtSignature ? googleMetadata({ thoughtSignature: part.thoughtSignature }) : undefined,
+        )
+        continue
+      }
+      lifecycle = Lifecycle.reasoningEnd(
+        lifecycle,
+        events,
+        "reasoning-0",
+        reasoningSignature ? googleMetadata({ thoughtSignature: reasoningSignature }) : undefined,
+      )
+      lifecycle = Lifecycle.textDelta(lifecycle, events, "text-0", part.text)
       continue
     }
 
     if ("functionCall" in part) {
       const input = part.functionCall.args
       const id = `tool_${nextToolCallId++}`
+      lifecycle = Lifecycle.reasoningEnd(
+        lifecycle,
+        events,
+        "reasoning-0",
+        reasoningSignature ? googleMetadata({ thoughtSignature: reasoningSignature }) : undefined,
+      )
       lifecycle = Lifecycle.stepStart(lifecycle, events)
       events.push(
         LLMEvent.toolCall({
diff --git a/packages/llm/src/protocols/openai-chat.ts b/packages/llm/src/protocols/openai-chat.ts
index e37eec95ec..4e41a34ce4 100644
--- a/packages/llm/src/protocols/openai-chat.ts
+++ b/packages/llm/src/protocols/openai-chat.ts
@@ -411,7 +411,12 @@ const step = (state: ParserState, event: OpenAIChatEvent) =>
     if (delta?.reasoning_content)
       lifecycle = Lifecycle.reasoningDelta(lifecycle, events, "reasoning-0", delta.reasoning_content)
 
-    if (delta?.content) lifecycle = Lifecycle.textDelta(lifecycle, events, "text-0", delta.content)
+    if (delta?.content) {
+      lifecycle = Lifecycle.reasoningEnd(lifecycle, events, "reasoning-0")
+      lifecycle = Lifecycle.textDelta(lifecycle, events, "text-0", delta.content)
+    }
+
+    if (toolDeltas.length) lifecycle = Lifecycle.reasoningEnd(lifecycle, events, "reasoning-0")
 
     for (const tool of toolDeltas) {
       const result = ToolStream.appendOrStart(
diff --git a/packages/llm/test/provider/gemini.test.ts b/packages/llm/test/provider/gemini.test.ts
index d30742c47d..1dc253c0ea 100644
--- a/packages/llm/test/provider/gemini.test.ts
+++ b/packages/llm/test/provider/gemini.test.ts
@@ -347,10 +347,10 @@ describe("Gemini route", () => {
         { type: "step-start", index: 0 },
         { type: "reasoning-start", id: "reasoning-0" },
         { type: "reasoning-delta", id: "reasoning-0", text: "thinking" },
+        { type: "reasoning-end", id: "reasoning-0" },
         { type: "text-start", id: "text-0" },
         { type: "text-delta", id: "text-0", text: "Hello" },
         { type: "text-delta", id: "text-0", text: "!" },
-        { type: "reasoning-end", id: "reasoning-0" },
         { type: "text-end", id: "text-0" },
         { type: "step-finish", index: 0, reason: "stop", usage, providerMetadata: undefined },
         {
@@ -399,6 +399,9 @@ describe("Gemini route", () => {
         providerMetadata: { google: { thoughtSignature: "thought_sig" } },
       })
       expect(toolCall).toMatchObject({ providerMetadata: { google: { thoughtSignature: "tool_sig" } } })
+      expect(response.events.findIndex((event) => event.type === "reasoning-end")).toBeLessThan(
+        response.events.findIndex((event) => event.type === "tool-call"),
+      )
 
       const prepared = yield* LLMClient.prepare<Gemini.GeminiBody>(
         LLM.request({
diff --git a/packages/llm/test/provider/openai-chat.test.ts b/packages/llm/test/provider/openai-chat.test.ts
index 5dbc89f1ae..02995c00ce 100644
--- a/packages/llm/test/provider/openai-chat.test.ts
+++ b/packages/llm/test/provider/openai-chat.test.ts
@@ -542,9 +542,9 @@ describe("OpenAI Chat route", () => {
         { type: "step-start", index: 0 },
         { type: "reasoning-start", id: "reasoning-0" },
         { type: "reasoning-delta", id: "reasoning-0", text: "thinking" },
+        { type: "reasoning-end", id: "reasoning-0" },
         { type: "text-start", id: "text-0" },
         { type: "text-delta", id: "text-0", text: "Hello" },
-        { type: "reasoning-end", id: "reasoning-0" },
         { type: "text-end", id: "text-0" },
         { type: "step-finish", index: 0, reason: "stop" },
         { type: "finish", reason: "stop" },