Feature Request: Expose message timestamps to the model and display them in the UI

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

After a week-long session with Claude Code (April 10-17, 2026), I found that Claude has no awareness of when messages were sent, leading to repeated confusion about dates, timelines, and scheduling. This is a fundamental gap — even LINE and SMS have had per-message timestamps since 2011.

1. The model cannot see message timestamps. Each message has a timestamp in the infrastructure layer (confirmed via .jsonl transcript), but the model cannot access it. Claude must run date shell commands as a workaround, which is unreliable (sandbox clocks can be wrong, UTC/JST mismatches occur). Users end up correcting Claude about what day it is, repeatedly.

1. The UI does not display timestamps. Unlike LINE, iMessage, Slack, or virtually any messaging app, Claude Code's chat UI does not show timestamps on messages. Users scrolling through a multi-day conversation cannot tell when each exchange happened.

1. Routines have timezone issues. A daily-briefing routine running at 05:30 JST reported the date as April 15 when it was actually April 16. The system-injected "Today's date" appears to use UTC, causing a 1-day offset for JST users.

Workarounds I had to build in CLAUDE.md: (1) Step 0: run TZ=Asia/Tokyo date before anything, (2) every response must include current time, (3) never ask the user what day it is, (4) routine prompts include explicit date verification. These should be product defaults.

Environment: Claude Code web/CLI/iOS. Max 20x plan. Asia/Tokyo (UTC+9). 7-day continuous session.

Proposed Solution

A. Expose timestamps to the model (highest impact): Include the timestamp of each message in the context the model sees, e.g. "[2026-04-15 07:10 JST] User: おはよう。" This single change would eliminate most confusion.

B. Display timestamps in the UI: Show timestamps on messages like LINE does — always visible or revealed on hover/swipe, with date separators between days.

C. Fix Routine timezone handling: Inject the correct local date/time (based on user's timezone setting) into Routine sessions, not UTC.

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

Interactive mode (TUI)

Use Case Example

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Additional Context

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