init claude-code

components/messages/nullRenderingAttachments.ts

@@ -0,0 +1,70 @@
+import type { Attachment } from 'src/utils/attachments.js'
+import type { Message, NormalizedMessage } from '../../types/message.js'
+
+/**
+ * Attachment types that AttachmentMessage renders as `null` unconditionally
+ * (no visible output regardless of runtime state). Messages.tsx filters these
+ * out BEFORE the render cap / message count so invisible entries don't consume
+ * the 200-message render budget (CC-724).
+ *
+ * Sync is enforced by TypeScript: AttachmentMessage's switch `default:` branch
+ * asserts `attachment.type satisfies NullRenderingAttachmentType`. Adding a new
+ * Attachment type without either a case or an entry here will fail typecheck.
+ */
+const NULL_RENDERING_TYPES = [
+  'hook_success',
+  'hook_additional_context',
+  'hook_cancelled',
+  'command_permissions',
+  'agent_mention',
+  'budget_usd',
+  'critical_system_reminder',
+  'edited_image_file',
+  'edited_text_file',
+  'opened_file_in_ide',
+  'output_style',
+  'plan_mode',
+  'plan_mode_exit',
+  'plan_mode_reentry',
+  'structured_output',
+  'team_context',
+  'todo_reminder',
+  'context_efficiency',
+  'deferred_tools_delta',
+  'mcp_instructions_delta',
+  'companion_intro',
+  'token_usage',
+  'ultrathink_effort',
+  'max_turns_reached',
+  'task_reminder',
+  'auto_mode',
+  'auto_mode_exit',
+  'output_token_usage',
+  'pen_mode_enter',
+  'pen_mode_exit',
+  'verify_plan_reminder',
+  'current_session_memory',
+  'compaction_reminder',
+  'date_change',
+] as const satisfies readonly Attachment['type'][]
+
+export type NullRenderingAttachmentType = (typeof NULL_RENDERING_TYPES)[number]
+
+const NULL_RENDERING_ATTACHMENT_TYPES: ReadonlySet<Attachment['type']> =
+  new Set(NULL_RENDERING_TYPES)
+
+/**
+ * True when this message is an attachment that AttachmentMessage renders as
+ * null with no visible output. Messages.tsx filters these out before counting
+ * and before applying the 200-message render cap, so invisible hook
+ * attachments (hook_success, hook_additional_context, hook_cancelled) don't
+ * inflate the "N messages" count or eat into the render budget (CC-724).
+ */
+export function isNullRenderingAttachment(
+  msg: Message | NormalizedMessage,
+): boolean {
+  return (
+    msg.type === 'attachment' &&
+    NULL_RENDERING_ATTACHMENT_TYPES.has(msg.attachment.type)
+  )
+}