conversation_participants

Overview

The conversation_participants table tracks which users belong to which conversations. It includes step-away tracking fields that record when a user has temporarily stepped away from a conversation, supporting the "absence is first-class" design principle.

Relevant Invariants

• Invariant #15: "Non-Interaction Is Valid" -- Step-away tracking normalizes absence
• Invariant #13: "Absence Is First-Class" -- Stepped-away state is an explicit, respected state

Schema

-- From 20260131_messaging_system.sql + 20260201_stepped_away_tracking.sql
CREATE TABLE conversation_participants (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  conversation_id UUID NOT NULL REFERENCES conversations(id) ON DELETE CASCADE,
  user_id UUID NOT NULL REFERENCES auth.users(id) ON DELETE CASCADE,
  joined_at TIMESTAMPTZ DEFAULT NOW(),
  -- Step-away tracking (20260201_stepped_away_tracking.sql)
  stepped_away_at TIMESTAMPTZ,
  step_away_prompted BOOLEAN DEFAULT FALSE,
  UNIQUE(conversation_id, user_id)
);

Columns

Column	Type	Nullable	Default	Description
id	uuid	No	gen_random_uuid()	Primary key
conversation_id	uuid	No	--	Conversation reference
user_id	uuid	No	--	Participant user
joined_at	timestamptz	No	NOW()	When user joined the conversation
stepped_away_at	timestamptz	Yes	--	When user stepped away (null = active)
step_away_prompted	boolean	No	FALSE	Whether user was prompted about stepping away

RLS Policies

-- SELECT: Conversation participants can see other participants
CREATE POLICY "Participants can view other participants"
  ON conversation_participants FOR SELECT
  USING (EXISTS (
    SELECT 1 FROM conversation_participants cp
    WHERE cp.conversation_id = conversation_participants.conversation_id
    AND cp.user_id = auth.uid()
  ));

-- UPDATE: Users can update their own participation (step away/return)
CREATE POLICY "Users can update own participation"
  ON conversation_participants FOR UPDATE
  USING (auth.uid() = user_id);

Related

• conversations -- Parent conversation
• profiles -- Participant user
• messages -- Messages in the conversation

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Last updated: 2026-02-07