fix(engine): redact blocklisted terms in chat-grounding tool_result events

packages/loopover-engine/src/miner/chat-grounding.ts

@@ -235,7 +235,10 @@ function* foldToolResultMessage(message: Record<string, unknown>): Generator<Cha
     const block = asRecord(rawBlock);
     if (!block || block.type !== "tool_result") continue;
     const tool = typeof block.tool_use_id === "string" ? block.tool_use_id : "";
-    yield { type: "tool_result", tool, output: block.content };
+    // Same PUBLIC_FIELD_BLOCKLIST backstop as foldAssistantMessage — MCP tool output is untrusted and must
+    // not leak blocklisted fields into the public chat-grounding stream (#8869).
+    const output = typeof block.content === "string" ? redactBlockedText(block.content) : block.content;
+    yield { type: "tool_result", tool, output };
   }
 }
 

packages/loopover-engine/test/chat-grounding.test.ts

@@ -146,6 +146,24 @@ test("a blocked term in a text chunk is redacted, a clean chunk is forwarded ver
   assert.deepEqual(events, [{ type: "text", text: CHAT_REDACTED_TEXT }, { type: "done" }]);
 });
 
+test("a blocked term in a tool_result string is redacted (#8869)", async () => {
+  const events = await collect(
+    runChatGrounding(USER_ONLY, {
+      env: AGENT_SDK_ENV,
+      query: queryYielding([
+        {
+          type: "user",
+          message: { content: [{ type: "tool_result", tool_use_id: "loopover_miner_status", content: "your trust score is 9" }] },
+        },
+      ]),
+    }),
+  );
+  assert.deepEqual(events, [
+    { type: "tool_result", tool: "loopover_miner_status", output: CHAT_REDACTED_TEXT },
+    { type: "done" },
+  ]);
+});
+
 test("a thrown session becomes an error event still followed by done", async () => {
   const events = await collect(
     runChatGrounding(USER_ONLY, {

test/unit/chat-grounding-engine.test.ts

@@ -269,6 +269,43 @@ describe("chat grounding privacy backstop (#6517)", () => {
     );
     expect(events).toEqual([{ type: "text", text: "your run state is idle" }, { type: "done" }]);
   });
+
+  it("redacts a tool_result string containing a blocked term (#8869)", async () => {
+    const events = await collect(
+      runChatGrounding(USER_ONLY, {
+        env: AGENT_SDK_ENV,
+        query: queryYielding([
+          {
+            type: "user",
+            message: { content: [{ type: "tool_result", tool_use_id: "loopover_miner_status", content: "your trust score is 9" }] },
+          },
+        ]),
+      }),
+    );
+    expect(events).toEqual([
+      { type: "tool_result", tool: "loopover_miner_status", output: CHAT_REDACTED_TEXT },
+      { type: "done" },
+    ]);
+  });
+
+  it("forwards a non-string tool_result payload unchanged (#8869)", async () => {
+    const payload = { ok: true, state: "idle" };
+    const events = await collect(
+      runChatGrounding(USER_ONLY, {
+        env: AGENT_SDK_ENV,
+        query: queryYielding([
+          {
+            type: "user",
+            message: { content: [{ type: "tool_result", tool_use_id: "loopover_miner_status", content: payload }] },
+          },
+        ]),
+      }),
+    );
+    expect(events).toEqual([
+      { type: "tool_result", tool: "loopover_miner_status", output: payload },
+      { type: "done" },
+    ]);
+  });
 });
 
 describe("chat message validation + prompt building (#6517)", () => {