From aa56045b492b1e01ad5836cabc43b2a4947b2bb3 Mon Sep 17 00:00:00 2001
From: Vignesh Natarajan <vigneshnatarajan92@gmail.com>
Date: Sat, 14 Feb 2026 20:09:04 -0800
Subject: [PATCH] fix (agents): harden transcript tool-call block sanitization

---
 .../session-transcript-repair.e2e.test.ts     | 26 +++++++++++++++++++
 src/agents/session-transcript-repair.ts       | 17 +++++++++++-
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/src/agents/session-transcript-repair.e2e.test.ts b/src/agents/session-transcript-repair.e2e.test.ts
index 8f2a30960..f03d9f6e0 100644
--- a/src/agents/session-transcript-repair.e2e.test.ts
+++ b/src/agents/session-transcript-repair.e2e.test.ts
@@ -223,6 +223,32 @@ describe("sanitizeToolCallInputs", () => {
     expect(out.map((m) => m.role)).toEqual(["user"]);
   });
 
+  it("drops tool calls with missing or blank name/id", () => {
+    const input: AgentMessage[] = [
+      {
+        role: "assistant",
+        content: [
+          { type: "toolCall", id: "call_ok", name: "read", arguments: {} },
+          { type: "toolCall", id: "call_empty_name", name: "", arguments: {} },
+          { type: "toolUse", id: "call_blank_name", name: "   ", input: {} },
+          { type: "functionCall", id: "", name: "exec", arguments: {} },
+        ],
+      },
+    ];
+
+    const out = sanitizeToolCallInputs(input);
+    const assistant = out[0] as Extract<AgentMessage, { role: "assistant" }>;
+    const toolCalls = Array.isArray(assistant.content)
+      ? assistant.content.filter((block) => {
+          const type = (block as { type?: unknown }).type;
+          return typeof type === "string" && ["toolCall", "toolUse", "functionCall"].includes(type);
+        })
+      : [];
+
+    expect(toolCalls).toHaveLength(1);
+    expect((toolCalls[0] as { id?: unknown }).id).toBe("call_ok");
+  });
+
   it("keeps valid tool calls and preserves text blocks", () => {
     const input: AgentMessage[] = [
       {
diff --git a/src/agents/session-transcript-repair.ts b/src/agents/session-transcript-repair.ts
index c8a6286e5..1ac325b1d 100644
--- a/src/agents/session-transcript-repair.ts
+++ b/src/agents/session-transcript-repair.ts
@@ -58,6 +58,18 @@ function hasToolCallInput(block: ToolCallBlock): boolean {
   return hasInput || hasArguments;
 }
 
+function hasNonEmptyStringField(value: unknown): boolean {
+  return typeof value === "string" && value.trim().length > 0;
+}
+
+function hasToolCallId(block: ToolCallBlock): boolean {
+  return hasNonEmptyStringField(block.id);
+}
+
+function hasToolCallName(block: ToolCallBlock): boolean {
+  return hasNonEmptyStringField(block.name);
+}
+
 function extractToolResultId(msg: Extract<AgentMessage, { role: "toolResult" }>): string | null {
   const toolCallId = (msg as { toolCallId?: unknown }).toolCallId;
   if (typeof toolCallId === "string" && toolCallId) {
@@ -118,7 +130,10 @@ export function repairToolCallInputs(messages: AgentMessage[]): ToolCallInputRep
     let droppedInMessage = 0;
 
     for (const block of msg.content) {
-      if (isToolCallBlock(block) && !hasToolCallInput(block)) {
+      if (
+        isToolCallBlock(block) &&
+        (!hasToolCallInput(block) || !hasToolCallId(block) || !hasToolCallName(block))
+      ) {
         droppedToolCalls += 1;
         droppedInMessage += 1;
         changed = true;