> ## Documentation Index
> Fetch the complete documentation index at: https://help.doozy.live/llms.txt
> Use this file to discover all available pages before exploring further.
# Cohort Trigger
> Run tracks when a cohort opens, or for each person when the cohort starts.
The **Cohort** trigger attaches a track to a [cohort
program](/cohorts/overview), so the track runs as part of each cohort that
program creates. Use it for onboarding intakes, training groups, and any
experience where people who start together should move through content together.
Cohorts is rolling out gradually (see the [Cohorts overview](/cohorts/overview)).
The track builder never offers this trigger directly. A cohort track is created
from a cohort program's page, so you need a program first: see [Cohort
programs](/cohorts/set-up-cohorts).
## Created from the program, fixed for life
A cohort track starts on its program's page. **Create a cohort track** and
**Create a per-person track** open the track editor with the trigger, the run
mode, and the
program already filled in, and the builder shows the trigger as **Cohort · Once
per cohort** or **Cohort · For each person**. Attaching tracks to a program
needs editor access on it (see [the People
list](/cohorts/set-up-cohorts#people)).
| Run mode | What it does | Good for |
| ------------------- | ------------------------------------------------------------------ | --------------------------------------------------------- |
| **Once per cohort** | Runs a single time when the cohort opens | Kickoff messages and shared content in the cohort channel |
| **For each person** | Runs for each person when the cohort starts, in their own timezone | Onboarding sequences, check-ins, and quizzes |
A program has at most **one** Once per cohort track, counting drafts, and any
number of For each person tracks. Archiving the cohort track frees the slot.
The run mode and program are the track's identity, so they're fixed from then
on. The builder shows both read-only, and an existing track can't be re-pointed
at a different program, switched to the other run mode, or turned into a cohort
track later. Filters, steps, and everything else stay editable. To change the
run mode or program, archive the track and create a new one.
The run mode determines which step types the track can contain. Steps that act
on an individual person, like Introductions, Mentor Assignment, Tasks, Add to
Track, or Webhook, can't run once per cohort. Each one shows an inline error,
and publishing is blocked until you resolve or remove them.
Archiving any track that's attached to a cohort program, not just a track built
this way, warns you first: the confirmation names the program and, if it still
has active or upcoming cohorts, says they'll lose this content when you go
through with it. It's a warning, not a block: archiving still goes ahead once
you confirm.
## Start from an existing track
Instead of building from scratch, **Import an existing track** on the program's
page copies one of your existing tracks into a new draft already wired to this
program and run mode, and opens it in the builder. The source track is never
changed. Only your non-archived, non-cohort tracks are offered, since a cohort
track already belongs to a program and can't be moved to another.
The copy carries over every step. Any that don't fit the chosen run mode, like
an Introductions or Tasks step imported into a once-per-cohort track, are kept
but flagged as invalid in the builder, the same as if you'd added them there
directly. Resolve or remove them before you can activate the copy.
## When per-person tracks start
A cohort has one clock: its first day. Day 1 of every per-person track is the
first day of the cohort's dates, at the program's [start
time](/cohorts/set-up-cohorts#start-time), read in each person's own timezone. A
9:00 AM start lands at 9:00 AM local time for everyone, and later steps count
from that same day. Per-person cohort tracks are not timed from each person's
own start date; that anchor belongs to the [First day
trigger](/tracks/triggers/first-day), a separate feature.
Most people land in a cohort days before it starts, and their tracks don't start
early. Each person is enrolled when the cohort opens, so the cohort, and its
channel if it has one, exists before anything is sent. Someone who joins on the
start day converges onto that clock: steps already due are delivered right away,
and the rest keep their scheduled days. Someone who joins after the start day is
enrolled and invited to the channel right away, and their track runs from the
beginning at the next weekday slot during business hours, counting forward from
there, rather than delivering past days all at once.
## Where each run mode sends
A **Once per cohort** track speaks to the group. Its steps post to the **cohort
channel** by default, so the whole cohort receives messages, quizzes, or surveys
together. A step can instead target a specific Slack channel, that channel's
members, specific people, or groups. Destinations relative to one person (User,
Manager, Mentor, and the like) aren't offered, because the track runs once for
the whole cohort.
There's no group DM option for a cohort. Slack caps group DMs at 9 people, so
the cohort channel is the cohort's one shared space.
A **For each person** track is a personal journey. Its steps deliver to the
person being onboarded, or their manager, mentor, and the other per-person
destinations, and can't send to the cohort channel. Group announcements belong
in the cohort track.
Sending to the cohort channel only works when the program actually has a
channel, meaning its **Slack channel** setting is **Create automatically** or
**Link existing**. If a track sends to the cohort channel but the program is set
to **No channel**, the track editor warns you and offers a one-click fix that
switches the program to create a channel for each cohort. Publishing is blocked
until the mismatch is resolved. If a published track ends up in this state
anyway, for example because the program was edited later, the channel step fails
with a stated reason and the rest of the track continues.
## Editing a published cohort track
You can edit a cohort track while cohorts are running through it. Edits apply to
steps that haven't been sent yet, including in runs already in progress. The
editor shows a notice reminding you of this when you edit a live cohort track.
## Related
How cohort programs, cohorts, and tracks fit together
Create a program: membership, schedule, and channel
Put the people who run each cohort in its channel
The track builder, step by step