Content calendar gap-fill: Notion → Slack → Todoist

Build the "Content Calendar" database

Create a new page → Table. Properties: Title (Title), Publish Date (Date), Owner (Person), Status (Status — values must sit in Notion's three built-in groups To-do / In Progress / Complete; the API's status-group filter and this workflow's placeholders key off the group). If this same calendar already feeds an approval-and-schedule pipeline, reuse its Status options and set gap placeholders to a To-do-group value (e.g. Idea or Drafting) — do not invent a parallel Status vocabulary on the shared database. If you reuse the same database as an approval/schedule pipeline that already named the date property Publish At (with time), filter and sort on that exact property name — do not add a second date column. Gap detection still normalizes to date-only before the set diff.

Build the "Content Rotation" database, kept separate

A second database, not extra properties bolted onto the calendar — rotation state is read and written by different logic than content status, and merging them couples the two. Properties only: Person (Person), Active (Checkbox — uncheck someone who is out or off the team instead of deleting the row), Last Assigned (Date). No Order column: sorting Active rows by Last Assigned ascending already gives a self-balancing queue; a separate ordinal is a second place to keep the same information in sync.

Connect the integration to both databases

Settings → Connections → New internal connection, name it, copy the token (ntn_ on integrations created recently, or secret_ on older ones — both work as Bearer today). Then, on each database, ••• (top right) → Connections → Add connection → your connection. Content Calendar needs Read, Update, and Insert content (this workflow creates placeholder rows on gap days); Content Rotation only needs Read and Update. Skipping either grant is what turns into a 404 on the query below or a 403 on the write-back.

Retrieve the calendar data source id and confirm the 7-day query

GET /v1/databases/{database_id} on the calendar returns data_sources[].id — queries and writes target that data source id, not the database id (Notion-Version: 2026-03-11 split the two). Compute the two date bounds yourself from the job's own clock rather than a Notion relative filter like next_week, so the window does not depend on when Notion last recalculated anything. Use your date property name in the filter (this seed's example uses Publish Date; if the shared DB already uses Publish At, substitute that exact name).

{
  "filter": {
    "and": [
      { "property": "Publish Date", "date": { "on_or_after": "2026-08-10" } },
      { "property": "Publish Date", "date": { "before": "2026-08-17" } }
    ]
  },
  "sorts": [{ "property": "Publish Date", "direction": "ascending" }]
}

Retrieve the rotation data source id; plan the per-gap write-back

Same GET /v1/databases/{database_id} against Content Rotation. The flow queries Active rows sorted by Last Assigned ascending, takes the first Person, then PATCHes that row's Last Assigned to today before picking the next gap day — skipping the immediate write-back is what assigns every empty day in one run to the same person. Use the page id from the rotation query result; Notion-Version: 2026-03-11. Date property shape PENDING-WEB confirm on developers.notion.com/reference/page-property-values.

{
  "filter": { "property": "Active", "checkbox": { "equals": true } },
  "sorts": [{ "property": "Last Assigned", "direction": "ascending" }]
}
---
PATCH /v1/pages/{rotation_page_id}
{
  "properties": {
    "Last Assigned": { "date": { "start": "2026-08-09" } }
  }
}

Create the app and add bot scopes

api.slack.com/apps → Create New App → From scratch → OAuth & Permissions → Bot Token Scopes: users:read.email (resolve the rotation Person's email to a Slack user id — plain users:read is not enough), im:write (open the DM), chat:write (send it). Install to the workspace for the bot token.

Look up the user, open a DM, post — then check the body

users.lookupByEmail on the assigned rotation row's email, conversations.open with that user id to get a channel id, then chat.postMessage to it. Slack wraps failures in an HTTP 200 — a bad token or missing scope still comes back {"ok":false,"error":"..."} at status 200, so read ok from the body on every call, not just the status code.

curl -s -G "https://slack.com/api/users.lookupByEmail" \
  -H "Authorization: Bearer $SLACK_BOT_TOKEN" \
  --data-urlencode "email=owner@company.com"

curl -X POST "https://slack.com/api/conversations.open" \
  -H "Authorization: Bearer $SLACK_BOT_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"users":"U0REP123"}'

curl -X POST "https://slack.com/api/chat.postMessage" \
  -H "Authorization: Bearer $SLACK_BOT_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"channel":"D0XXXXXXX","text":"You are up: Aug 14 has no draft on the calendar. New placeholder row + Todoist task created."}'

Create the fallback channel for a fully inactive roster

Create #content-calendar (or reuse an existing editorial channel) and keep its channel id in config. When every Content Rotation row is unchecked, the flow cannot DM anyone — it posts the gap alert there instead. Skipping this step is fine only if you accept "all inactive → log and skip notify" as the failure mode; otherwise this channel is required for that branch.

Create a dedicated project

Make a "Content Calendar" project and copy its project_id from the URL (or GET /api/v1/projects), so gap-fill tasks land somewhere separate from anyone's personal to-do list.

Grab a personal API token

Todoist web app → avatar → Integrations → Developer → copy the API token. Bearer auth, no OAuth flow to run.

Pull collaborators once and check your plan tier

GET the project's collaborators to map each rotation Person's email to a Todoist user_id for assignee_id. Todoist's pricing page lists "Assigned tasks" under Pro/Business only, not Free/Beginner — on Free, drop assignee_id and put the owner's name in the task content instead. POST to /api/v1/tasks; /rest/v2/tasks returns 410 Gone.

curl -X POST "https://api.todoist.com/api/v1/tasks" \
  -H "Authorization: Bearer $TODOIST_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "content": "Draft: 2026-08-14 content slot (gap-fill)",
    "project_id": "2203306141",
    "due_date": "2026-08-13",
    "assignee_id": "6X6WMMqgq2PWxjCX"
  }'