Prefix user messages with local time (as a UserPromptSubmit hook can already do)

What's missing

Claude receives no time information between messages. In a long session it cannot situate events, measure elapsed durations, or notice that an hour has passed since the last exchange.

Suggestion

Prefix each user message with the local time, exactly as a UserPromptSubmit hook can already do:

Local time: 15:39

Why it matters — from an actual long session

I run this via a hook, and over an eleven-hour session it was used to:

• date the exact moment a background task was killed, and correlate it with system journals
• measure the real throughput of a long-running job (items completed per minute) and correct three successive wrong estimates — without timestamps, each of those measurements was either impossible or wrong
• notice a session had been running for seven hours, which redirected a diagnosis

Note

Since it's already achievable with a hook, the implementation is trivial. The value of making it native is that most users will never configure a hook, and silently lose this information.

Privacy

Local time indirectly reveals the timezone, so this should probably be a setting rather than an imposed default.