diff --git a/packages/cli/src/types/sentry.ts b/packages/cli/src/types/sentry.ts
index 3a21f2be4..c9b9a137d 100644
--- a/packages/cli/src/types/sentry.ts
+++ b/packages/cli/src/types/sentry.ts
@@ -1056,7 +1056,13 @@ export type DetailedLogsResponse = InferOutput<
  */
 export const TraceItemAttributeSchema = variant("type", [
   object({ name: string(), type: literal("str"), value: string() }),
-  object({ name: string(), type: literal("int"), value: number() }),
+  // Sentry serializes int64 values as strings to avoid precision loss
+  // (e.g. project_id: "4508608809533441"); keep them as strings.
+  object({
+    name: string(),
+    type: literal("int"),
+    value: union([number(), string()]),
+  }),
   object({ name: string(), type: literal("float"), value: number() }),
   object({ name: string(), type: literal("bool"), value: boolean() }),
   // "array" is gated by organizations:trace-item-details-array-fields in Sentry backend
diff --git a/packages/cli/test/lib/api/traces.test.ts b/packages/cli/test/lib/api/traces.test.ts
index 432ca06eb..9b6cb5ac0 100644
--- a/packages/cli/test/lib/api/traces.test.ts
+++ b/packages/cli/test/lib/api/traces.test.ts
@@ -731,6 +731,29 @@ describe("getSpanDetails", () => {
       value: "db.query",
     });
   });
+
+  test("accepts int attributes serialized as strings", async () => {
+    mockOk({
+      ...DETAIL_RESPONSE,
+      attributes: [
+        { name: "project_id", type: "int", value: "4508608809533441" },
+        { name: "retry.count", type: "int", value: 3 },
+      ],
+    });
+
+    const result = await getSpanDetails(
+      "my-org",
+      "my-project",
+      "span-id-abc",
+      "trace-id-xyz",
+    );
+
+    // Strings are kept as-is so int64 IDs don't lose precision
+    expect(result.attributes).toEqual([
+      { name: "project_id", type: "int", value: "4508608809533441" },
+      { name: "retry.count", type: "int", value: 3 },
+    ]);
+  });
 });
 
 // ---------------------------------------------------------------------------