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POST
/
threads
/
{thread_id}
/
stream
/
events
Protocol v2 Event Stream (SSE)
curl --request POST \
  --url https://api.example.com/threads/{thread_id}/stream/events \
  --header 'Content-Type: application/json' \
  --data '
{
  "channels": [
    "values"
  ],
  "namespaces": [
    [
      "<string>"
    ]
  ],
  "depth": 1,
  "since": 1
}
'
"<string>"

Documentation Index

Fetch the complete documentation index at: https://docs.langchain.com/llms.txt

Use this file to discover all available pages before exploring further.

Path Parameters

​
thread_id
string<uuid>
required

The ID of the thread to observe.

Body

application/json

Body of POST /threads/{thread_id}/stream/events. Filters the connection-scoped SSE stream.

​
channels
(enum<string> | string)[]
required

Channels to subscribe to for the lifetime of this connection.

Minimum array length: 1

Subscribable event channel. One of the eight fixed channels or a user-defined custom:<name> namespaced custom channel emitted by a stream transformer. debug and checkpoints were removed from the protocol in @langchain/protocol@0.0.10 — task-level debug info now flows on the tasks channel, and checkpoint pointers ride on values events as an attached checkpoint envelope.

Available options:
values,
updates,
messages,
tools,
lifecycle,
input,
tasks,
custom
​
namespaces
string[][]

Prefix-match filter. An event matches if its namespace starts with any of these prefixes. Omit for all namespaces.

Hierarchical path identifying a position in the agent tree. Empty array denotes the root agent; each segment names a nested subgraph.

​
depth
integer

Max depth below the namespace prefix. Omit for unbounded depth.

Required range: x >= 0
​
since
integer

Replay events with seq greater than this value before streaming live events.

Required range: x >= 0

Response

SSE event stream

Stream of ProtocolEvent frames. Each SSE frame uses the event's method as the event: field and a JSON-encoded ProtocolEvent as the data: field; id: is set to the event's seq.

Example frame:

id: 42

event: messages

data: {"type":"event","event_id":"42","seq":42,"method":"messages","params":{"namespace":[],"timestamp":1700000000000,"data":{...}}}