From d0614b4b4e950516ad4f1abc0516667a01f5f177 Mon Sep 17 00:00:00 2001
From: Shakker <shakkerdroid@gmail.com>
Date: Sun, 12 Apr 2026 03:43:25 +0100
Subject: [PATCH] fix: drop dangling signed-thinking tool turns during
 anthropic validation

---
 ...pi-embedded-helpers.validate-turns.test.ts | 44 +++++++++++++++----
 src/agents/pi-embedded-helpers/turns.ts       | 26 +++++++++--
 2 files changed, 58 insertions(+), 12 deletions(-)

diff --git a/src/agents/pi-embedded-helpers.validate-turns.test.ts b/src/agents/pi-embedded-helpers.validate-turns.test.ts
index 7730844dc0a..725249778f4 100644
--- a/src/agents/pi-embedded-helpers.validate-turns.test.ts
+++ b/src/agents/pi-embedded-helpers.validate-turns.test.ts
@@ -525,7 +525,37 @@ describe("validateAnthropicTurns strips dangling tool_use blocks", () => {
     ]);
   });
 
-  it("preserves assistant turns that include signed thinking blocks", () => {
+  it("preserves signed-thinking turns whose sibling tool calls still resolve", () => {
+    const msgs = asMessages([
+      { role: "user", content: [{ type: "text", text: "Use tool" }] },
+      {
+        role: "assistant",
+        content: [
+          { type: "thinking", thinking: "internal", thinkingSignature: "sig_1" },
+          { type: "toolCall", id: "tool-1", name: "gateway", arguments: {} },
+        ],
+      },
+      {
+        role: "toolResult",
+        toolCallId: "tool-1",
+        toolName: "gateway",
+        content: [{ type: "text", text: "ok" }],
+        isError: false,
+      },
+      { role: "user", content: [{ type: "text", text: "Continue" }] },
+    ]);
+
+    const result = validateAnthropicTurns(msgs);
+
+    expect(result).toHaveLength(4);
+    const assistantContent = (result[1] as { content?: unknown[] }).content;
+    expect(assistantContent).toEqual([
+      { type: "thinking", thinking: "internal", thinkingSignature: "sig_1" },
+      { type: "toolCall", id: "tool-1", name: "gateway", arguments: {} },
+    ]);
+  });
+
+  it("drops signed-thinking turns whose sibling tool calls are dangling", () => {
     const msgs = asMessages([
       { role: "user", content: [{ type: "text", text: "Use tool" }] },
       {
@@ -541,14 +571,13 @@ describe("validateAnthropicTurns strips dangling tool_use blocks", () => {
     const result = validateAnthropicTurns(msgs);
 
     expect(result).toHaveLength(3);
-    const assistantContent = (result[1] as { content?: unknown[] }).content;
-    expect(assistantContent).toEqual([
-      { type: "thinking", thinking: "internal", thinkingSignature: "sig_1" },
-      { type: "toolCall", id: "tool-1", name: "gateway", arguments: {} },
+    expect((result[1] as { role?: unknown }).role).toBe("assistant");
+    expect((result[1] as { content?: unknown[] }).content).toEqual([
+      { type: "text", text: "[tool calls omitted]" },
     ]);
   });
 
-  it("preserves assistant turns that include redacted thinking blocks", () => {
+  it("drops redacted-thinking turns whose sibling tool calls are dangling", () => {
     const msgs = asMessages([
       { role: "user", content: [{ type: "text", text: "Use tool" }] },
       {
@@ -566,8 +595,7 @@ describe("validateAnthropicTurns strips dangling tool_use blocks", () => {
     expect(result).toHaveLength(3);
     const assistantContent = (result[1] as { content?: unknown[] }).content;
     expect(assistantContent).toEqual([
-      { type: "redacted_thinking", data: "blob", thinkingSignature: "sig_1" },
-      { type: "toolUse", id: "tool-1", name: "gateway", arguments: {} },
+      { type: "text", text: "[tool calls omitted]" },
     ]);
   });
 
diff --git a/src/agents/pi-embedded-helpers/turns.ts b/src/agents/pi-embedded-helpers/turns.ts
index 43bcf77e79e..ea40dedb5b3 100644
--- a/src/agents/pi-embedded-helpers/turns.ts
+++ b/src/agents/pi-embedded-helpers/turns.ts
@@ -125,10 +125,6 @@ function stripDanglingAnthropicToolUses(messages: AgentMessage[]): AgentMessage[
       result.push(msg);
       continue;
     }
-    if (originalContent.some((block) => isThinkingLikeBlock(block))) {
-      result.push(msg);
-      continue;
-    }
     if (
       extractToolCallsFromAssistant(msg as Extract<AgentMessage, { role: "assistant" }>).length ===
       0
@@ -136,8 +132,30 @@ function stripDanglingAnthropicToolUses(messages: AgentMessage[]): AgentMessage[
       result.push(msg);
       continue;
     }
+    const hasThinking = originalContent.some((block) => isThinkingLikeBlock(block));
     const validToolUseIds = collectFutureToolResultIds(messages, i);
 
+    if (hasThinking) {
+      const allToolCallsResolvable = originalContent.every((block) => {
+        if (!block || !isToolCallBlock(block)) {
+          return true;
+        }
+        const blockId = normalizeOptionalString(block.id);
+        return blockId ? validToolUseIds.has(blockId) : false;
+      });
+      if (allToolCallsResolvable) {
+        result.push(msg);
+      } else {
+        result.push({
+          ...assistantMsg,
+          content: isAbortedAssistantTurn(msg)
+            ? []
+            : ([{ type: "text", text: "[tool calls omitted]" }] as AnthropicContentBlock[]),
+        } as AgentMessage);
+      }
+      continue;
+    }
+
     const filteredContent = originalContent.filter((block) => {
       if (!block) {
         return false;