feedback_uk_local_time_default

Rule: All timestamps Claude writes (frontmatter date / lastmod, commit messages, prose dates, ntfy heartbeats, prompt output) must be in UK local time — BST (UTC+1) from the last Sunday of March to the last Sunday of October, GMT (UTC+0) otherwise. Per global CLAUDE.md §3, frontmatter is ISO 8601 local time, minute precision: YYYY-MM-DDTHH:MM. Prose dates include the weekday: Thursday 30 April 2026, 15:55 BST.

Why: Rich has repeatedly caught Claude writing wrong times in documents and prompts (latest correction: 2026-04-30, anchor “it is now 15:55”). The root cause is that Claude Code’s system context only injects currentDate (date) — not current time — so without an explicit anchor, time gets fabricated from training-data priors or stale session context, often defaulting to UTC, US-style, or “morning”. Wrong timestamps in lastmod break the ordering function of minute-precision frontmatter (§3 says “Multiple edits on the same day are common — date-only precision loses the ordering”) and corrupt the audit trail across all 7 in-scope repos.

How to apply:

• At session start, if the work involves writing timestamps, derive current UK local time from the most recent anchor in the conversation (user message, hook output, prior tool result). If no anchor exists and a timestamp matters, ASK Rich for the current time before writing — do not guess.
• DST awareness: today (2026-04-30) is BST. The DST window for 2026 is 2026-03-29 → 2026-10-25. Outside that window use GMT. Note “BST” or “GMT” explicitly in prose dates so Rich can verify at a glance.
• Frontmatter: date: 2026-04-30T15:55 and lastmod: 2026-04-30T15:55 — local time, no timezone suffix (per §3 convention).
• Prose: Thursday 30 April 2026, 15:55 BST — weekday + day + month + year + time + zone.
• Commit messages / ntfy / prompts: UK local time. If the only available anchor is hours old, prefer “this afternoon” / “earlier today” over fabricating HH:MM.
• Verification before completion: when you write a lastmod value, double-check it against the latest known anchor — wrong lastmod is the most common failure mode and the most damaging because it silently corrupts ordering.

Anti-pattern: writing lastmod: 2026-04-30T09:30 because “morning feels right” when the actual session anchor is 15:55 BST. Anchor-or-ask, never guess.