docs/date-time.md
OpenClaw uses host-local time for transport timestamps and puts only the time zone in the system prompt.
Provider timestamps are preserved so tools keep their native semantics. When the agent needs the current
time, it runs the session_status tool.
Inbound messages are wrapped with a weekday plus second-precision timestamp:
[WhatsApp +1555 Mon 2026-01-05 16:26:34 PST] message text
The envelope timestamp is host-local by default, regardless of the provider timezone.
Override under agents.defaults:
{
agents: {
defaults: {
envelopeTimezone: "local", // "utc" | "local" | "user" | IANA timezone
envelopeTimestamp: "on", // "on" | "off"
envelopeElapsed: "on", // "on" | "off"
},
},
}
| Key | Values | Behavior |
|---|---|---|
envelopeTimezone | local (default), utc, user, explicit IANA name | user uses agents.defaults.userTimezone (host timezone when unset). An explicit IANA name (e.g. "America/Chicago") pins a fixed zone; unrecognized names fall back to UTC. |
envelopeTimestamp | on (default), off | off removes absolute timestamps from envelope headers, direct agent prompt prefixes, and embedded model-input prefixes. |
envelopeElapsed | on (default), off | off removes the elapsed-time suffix (the +30s / +2m style) shown since the previous message in the session. |
Local (default):
[WhatsApp +1555 Sun 2026-01-18 00:19:42 PST] hello
User timezone:
[WhatsApp +1555 Sun 2026-01-18 00:19:42 CST] hello
Elapsed time with envelopeTimezone: "utc":
[WhatsApp +1555 +30s Sun 2026-01-18T05:19:00Z] follow-up
The system prompt includes a Current Date & Time section with the time zone only (no clock or time format) so prompt caching stays stable:
Time zone: America/Chicago
The zone is agents.defaults.userTimezone when configured, otherwise the host timezone.
The prompt also instructs the agent to run the session_status tool whenever it needs the
current date, time, or day of week.
Queued system events inserted into agent context are prefixed with a timestamp using the
same envelopeTimezone selection as message envelopes (default: host-local).
System: [2026-01-12 12:19:17 PST] Model switched.
{
agents: {
defaults: {
userTimezone: "America/Chicago",
timeFormat: "auto", // auto | 12 | 24
},
},
}
userTimezone sets the user-local timezone for prompt context (and for envelopeTimezone: "user").timeFormat controls 12h/24h display in prompt-facing times. auto follows OS preferences.When timeFormat: "auto", OpenClaw inspects the OS preference (macOS and Windows)
and falls back to locale formatting. The detected value is cached per process
to avoid repeated system calls.
Channel tools return provider-native timestamps and add normalized fields for consistency:
timestampMs: epoch milliseconds (UTC)timestampUtc: ISO 8601 UTC stringRaw provider fields are preserved so nothing is lost.
If you need local time, convert it downstream using the known timezone.