Skip to main content

​
Timezones

Fased standardizes timestamps so the model sees a single reference time.

​
Message envelopes (local by default)

Inbound messages are wrapped in an envelope like: 
[Provider ... 2026-01-05 16:26 PST] message text
The timestamp in the envelope is host-local by default, with minutes precision. You can override this with: 
{
  agents: {
    defaults: {
      envelopeTimezone: "local", // "utc" | "local" | "user" | IANA timezone
      envelopeTimestamp: "on", // "on" | "off"
      envelopeElapsed: "on", // "on" | "off"
    },
  },
}
  • envelopeTimezone: "utc" uses UTC.
  • envelopeTimezone: "user" uses agents.defaults.userTimezone (falls back to host timezone).
  • Use an explicit IANA timezone (e.g., "Europe/Vienna") for a fixed offset.
  • envelopeTimestamp: "off" removes absolute timestamps from envelope headers.
  • envelopeElapsed: "off" removes elapsed time suffixes (the +2m style).

​
Examples

Local (default): 
[Signal Alice +1555 2026-01-18 00:19 PST] hello
Fixed timezone: 
[Signal Alice +1555 2026-01-18 06:19 GMT+1] hello
Elapsed time: 
[Signal Alice +1555 +2m 2026-01-18T05:19Z] follow-up

​
Tool payloads (raw provider data + normalized fields)

Tool calls (channels.discord.readMessages, channels.slack.readMessages, etc.) return raw provider timestamps. We also attach normalized fields for consistency:
  • timestampMs (UTC epoch milliseconds)
  • timestampUtc (ISO 8601 UTC string)
Raw provider fields are preserved.

​
User timezone for the system prompt

Set agents.defaults.userTimezone to tell the model the user’s local time zone. If it is unset, Fased resolves the host timezone at runtime (no config write). 
{
  agents: { defaults: { userTimezone: "America/Chicago" } },
}
The system prompt includes a Current Date & Time section with:
  • Time zone: <resolved IANA timezone>
It intentionally does not include a live clock, date, or time format so prompt caching stays stable. Use session_status when the Agent needs the current time. agents.defaults.timeFormat (auto | 12 | 24) controls display in session_status and cron-style current-time lines, not the system prompt body. See Date & Time for the full behavior and examples.