init claude-code

utils/contentArray.ts

@@ -0,0 +1,51 @@
+/**
+ * Utility for inserting a block into a content array relative to tool_result
+ * blocks. Used by the API layer to position supplementary content (e.g.,
+ * cache editing directives) correctly within user messages.
+ *
+ * Placement rules:
+ * - If tool_result blocks exist: insert after the last one
+ * - Otherwise: insert before the last block
+ * - If the inserted block would be the final element, a text continuation
+ *   block is appended (some APIs require the prompt not to end with
+ *   non-text content)
+ */
+
+/**
+ * Inserts a block into the content array after the last tool_result block.
+ * Mutates the array in place.
+ *
+ * @param content - The content array to modify
+ * @param block - The block to insert
+ */
+export function insertBlockAfterToolResults(
+  content: unknown[],
+  block: unknown,
+): void {
+  // Find position after the last tool_result block
+  let lastToolResultIndex = -1
+  for (let i = 0; i < content.length; i++) {
+    const item = content[i]
+    if (
+      item &&
+      typeof item === 'object' &&
+      'type' in item &&
+      (item as { type: string }).type === 'tool_result'
+    ) {
+      lastToolResultIndex = i
+    }
+  }
+
+  if (lastToolResultIndex >= 0) {
+    const insertPos = lastToolResultIndex + 1
+    content.splice(insertPos, 0, block)
+    // Append a text continuation if the inserted block is now last
+    if (insertPos === content.length - 1) {
+      content.push({ type: 'text', text: '.' })
+    }
+  } else {
+    // No tool_result blocks — insert before the last block
+    const insertIndex = Math.max(0, content.length - 1)
+    content.splice(insertIndex, 0, block)
+  }
+}