Deploys

A deploy marker tells Mast you just shipped. Mast checks every probe on that channel right away instead of waiting out each probe's interval. If a page opens within the hour, it starts by naming the deploy:

3 min after deploy v2026-10-20 (a1b2c3d), from GitHub Actions #418.

Add wait= and the marker becomes a gate: the request stays open until the probes have been checked, and it fails when one of them is down. Put it as the last step of a deploy job and a broken release fails the job that shipped it.

Every example uses a channel's URL, https://mast.tissue.dev/mk_8e2a…, the same one you send messages to. Probes that page into that channel are the ones a marker checks. GET and POST both work.

Send a marker

curl -fsS "https://mast.tissue.dev/mk_8e2a…/deploy?v=v2026-10-20&sha=a1b2c3d4e5f6"

The answer comes back at once with 202:

{"ok":true,"id":"dp_…","label":"v2026-10-20 (a1b2c3d)","version":"v2026-10-20","sha":"a1b2c3d4e5f6","at":"2026-10-20T14:02:11.402Z","burst":3,"check_at":"2026-10-20T14:02:11.402Z"}

burst is how many probes were moved up to check at check_at. They run on the prober's next round, within a few seconds.

Field	What it is
`v` or `version`	The version you shipped, up to 64 characters. A date plus the short commit reads well on a phone: `v2026-10-20`.
`sha` or `commit`	The commit, 4 to 64 hex digits. The page shows the first 7.
`source`	Where the deploy ran, up to 120 characters: `GitHub Actions #418`, `deploy.sh on build-01`.
`url`	A link to the run. It has to be `https://`. Anything else is dropped and the answer carries a `warning`.
`wait`	1 to 300 seconds. Hold the request until the probes settle. See the next section.

Send v, sha or both. The fields can go in the query string, a form body or a JSON body. When the same field is in both, the query string wins.

curl -fsS -X POST https://mast.tissue.dev/mk_8e2a…/deploy \
  -H 'content-type: application/json' \
  -d '{"version":"v2026-10-20","sha":"a1b2c3d4e5f6","source":"deploy.sh on build-01"}'

Wait for the probes

curl -fsS --max-time 200 "https://mast.tissue.dev/mk_8e2a…/deploy?v=v2026-10-20&sha=a1b2c3d4e5f6&wait=180"

With wait, the request answers once every probe on the channel has been checked after the marker and has settled:

Status	When
`200`	Every probe answered. `gate` is `up`, or `degraded` when one fails from some places but not enough to page.
`503`	A probe is confirmed down. It answers as soon as that happens. `gate` is `down` and `message` names the probe and what failed.
`504`	The wait ran out before every probe settled. `gate` is `pending`.

curl -f turns 503 and 504 into a failed step. The body lists each probe with its verdict, state, checked_at and detail, so the job log says which one broke.

A probe settles the same way it does for paging. A first failure is rechecked 10 seconds later before it counts as down, and a down probe needs two good rounds to come back. Allow a minute or more on top of the slowest probe's timeout. A channel with no probes answers 200 with a warning, because there was nothing to check.

Set curl's --max-time a little above wait, so curl doesn't give up before Mast answers.

GitHub Actions

- name: Tell Mast
  if: success()
  run: |
    curl -fsS --max-time 200 \
      "https://mast.tissue.dev/${{ secrets.MAST_KEY }}/deploy?wait=180" \
      --data-urlencode "v=v$(date -u +%Y-%m-%d)" \
      --data-urlencode "sha=${{ github.sha }}" \
      --data-urlencode "source=GitHub Actions #${{ github.run_number }}" \
      --data-urlencode "url=${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"

MAST_KEY is the mk_… part of the channel URL, kept as a repository secret. --data-urlencode makes this a POST with a form body.

On the page

When a probe or a vital on the channel goes down within an hour of a marker, the page and the incident card start with the deploy. The card's evidence keeps the full commit, the time and the link to the run. A deploy longer ago than that is listed in the evidence only.

The probe's screen in the app lists the channel's latest deploys.

Limits

A channel's probes are moved up at most once a minute. A second marker inside that minute is recorded, and its probes check a minute after the first burst.
An account can hold 5 wait requests open at once. A sixth gets 429 with Retry-After.
Markers count against the channel's send rate limit like any other message.
Markers are kept for 90 days, and they're deleted with their channel.

Reading them back

GET /v1/mast/deploys lists your markers, newest first. Add channel_id for one channel and limit for up to 50. GET /v1/mast/probes/{id} carries the newest 10 on the probe's channel as deploys. See the API.