init claude-code

memdir/memoryAge.ts

@@ -0,0 +1,53 @@
+/**
+ * Days elapsed since mtime.  Floor-rounded — 0 for today, 1 for
+ * yesterday, 2+ for older.  Negative inputs (future mtime, clock skew)
+ * clamp to 0.
+ */
+export function memoryAgeDays(mtimeMs: number): number {
+  return Math.max(0, Math.floor((Date.now() - mtimeMs) / 86_400_000))
+}
+
+/**
+ * Human-readable age string.  Models are poor at date arithmetic —
+ * a raw ISO timestamp doesn't trigger staleness reasoning the way
+ * "47 days ago" does.
+ */
+export function memoryAge(mtimeMs: number): string {
+  const d = memoryAgeDays(mtimeMs)
+  if (d === 0) return 'today'
+  if (d === 1) return 'yesterday'
+  return `${d} days ago`
+}
+
+/**
+ * Plain-text staleness caveat for memories >1 day old.  Returns ''
+ * for fresh (today/yesterday) memories — warning there is noise.
+ *
+ * Use this when the consumer already provides its own wrapping
+ * (e.g. messages.ts relevant_memories → wrapMessagesInSystemReminder).
+ *
+ * Motivated by user reports of stale code-state memories (file:line
+ * citations to code that has since changed) being asserted as fact —
+ * the citation makes the stale claim sound more authoritative, not less.
+ */
+export function memoryFreshnessText(mtimeMs: number): string {
+  const d = memoryAgeDays(mtimeMs)
+  if (d <= 1) return ''
+  return (
+    `This memory is ${d} days old. ` +
+    `Memories are point-in-time observations, not live state — ` +
+    `claims about code behavior or file:line citations may be outdated. ` +
+    `Verify against current code before asserting as fact.`
+  )
+}
+
+/**
+ * Per-memory staleness note wrapped in <system-reminder> tags.
+ * Returns '' for memories ≤ 1 day old.  Use this for callers that
+ * don't add their own system-reminder wrapper (e.g. FileReadTool output).
+ */
+export function memoryFreshnessNote(mtimeMs: number): string {
+  const text = memoryFreshnessText(mtimeMs)
+  if (!text) return ''
+  return `<system-reminder>${text}</system-reminder>\n`
+}