> ## Documentation Index > Fetch the complete documentation index at: https://9cf5990-opencomputer.manicule.dev/llms.txt > Use this file to discover all available pages before exploring further. > For every page in one file, fetch https://9cf5990-opencomputer.manicule.dev/llms-full.txt (large). > To search and read these docs as tools, connect the MCP server at https://9cf5990-opencomputer.manicule.dev/api/mcp. > Every agent surface: https://9cf5990-opencomputer.manicule.dev/.well-known/llms-manifest.json # Events (/api/events) Related: [Overview](/api/overview.md), [Sessions](/api/sessions.md), [Turns](/api/turns.md), [Asks](/api/asks.md), [Subagents](/api/subagents.md), [Terminals](/api/terminals.md) > A session's events are numbered by `seq` from 1 with no gaps; read them over HTTP or follow them live over WebSocket ```json {"id":"ev_0123456789abcdef","seq":412,"createdAt":"2026-01-01T12:00:00.000Z","sessionId":"cs_0123456789abcdef","turnId":"tn_0123456789ab","actor":{"id":"usr_...","name":"Ada","via":"opc","client":"opc/0.1.0"},"type":"message.received","data":{"input":"Add a test for the empty case","ifBusy":"steer","delivery":"steered","interruptedTurnIds":[],"declinedAskIds":[]}} ``` `actor` is who caused the event (`via` is `slack`, `opc`, `dashboard` or `api`), or null. Event types and their `data` fields: [API schema](/reference/api-schema#events). A client must ignore types it does not know. ## Read a range `events.list` (`GET /sessions/{id}/events`) returns events in `seq` order. To follow a session over HTTP, loop on it with `after` and `waitMs`. ``` GET /sessions/cs_0123456789abcdef/events?after=400&limit=100&types=turn.*,ask.opened ``` | Param | Meaning | | ----------- | ---------------------------------------------------------------------------------------------------------------------------------- | | `after` | Return events with `seq` greater than this. Default 0, the start of the journal | | `limit` | 1 to 500 events. Default 100 | | `tailTurns` | Start at the last 1 to 50 turns instead; `earlierTurns` in the result holds the turns before them. Cannot be combined with `after` | | `turnId` | Only events of this turn | | `types` | A comma-separated list of types. A trailing `*` matches a prefix | | `waitMs` | When there is nothing after `after`, wait up to this long (at most 60,000) for an event | The result is `events`, `earlierTurns`, `lastSeq` (the journal's last `seq`) and `hasMore`. | `hasMore` | Next `after` | | --------- | --------------------------------------------------------------------------- | | true | The `seq` of the last event returned | | false | `lastSeq`. With a filter, the page may be shorter than the range it covered | | Error | Cause | | ------------------ | ----------------------------------------------------------------------------------------------------------------------------- | | `409 cursor_ahead` | `after` is beyond the journal's last `seq`: the journal's epoch changed. See [Session journal](/api/overview#session-journal) | ## Follow live [Attach](/api/sessions#attach) over WebSocket. Each event arrives as an `event` notification whose `params` is the event: ```json {"jsonrpc":"2.0","method":"event","params":{"id":"ev_...","seq":413,"type":"turn.steered","...":"..."}} ``` Order on one connection: * Events of a session arrive in `seq` order, each once. * The response to `sessions.attach` arrives before any replayed event. * The response to a write arrives before any event of that session the write caused. When the whole connection closes, reconnect and attach with `after` set to the last `seq` processed. A runner starting or stopping does not interrupt the subscription. | Error | Cause | What to do | | ---------------- | -------------------------------------------------- | ----------------------------------------------------------------- | | `too_far_behind` | Attach with `after` more than 10,000 events behind | Read the gap with `events.list` first, or attach with `tailTurns` | ### Acknowledge Send `sessions.ack` notifications as events are processed: ```json {"jsonrpc":"2.0","method":"sessions.ack","params":{"sessionId":"cs_0123456789abcdef","seq":413}} ``` The backlog of a session is its events not yet sent or, once the client has sent an ack, not yet acknowledged. When it passes 10,000 events or 8 MiB, the server detaches that session with `too_far_behind`. ### Deltas An attach with `deltas: true` also receives `delta` notifications. Types: [API schema](/reference/api-schema#deltas). | Property | Detail | | ------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------- | | Content | Message and reasoning text as it is written, a tool call being prepared and its output, compaction, subagent progress | | Storage | No `seq`, not stored, not replayed | | Completeness | Each block of deltas is followed by an event with the whole text (`message.completed`, `reasoning.completed`, `tool.completed`). A client may ignore deltas | | Backlog | Sent only to a subscription that has been sent every event. Deltas of one block that wait are merged | ### Detached When the server ends a subscription it sends `session.detached` with a `reason`: | `reason` | Cause | What to do | | ---------------- | ---------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------- | | `too_far_behind` | The backlog passed its limit | Attach again with `after` set to the last `seq` processed | | `access_lost` | The member no longer has access to the session | Nothing | | `epoch_changed` | The journal was rebuilt. The notification carries the new `logEpoch` and `epochStartSeq` | Discard events from `epochStartSeq` on and attach with `after` set to `epochStartSeq - 1` | | `unavailable` | The session's writer could not be reached | Attach again later |