Prediction Endpoint Streaming Intermittently Returns No Content

[EanMcDonaldWojciechowski]

Describe the bug

Streaming is inconsistently broken on the /prediction/{id} endpoint. Typically, Flowise will stream "event" => "metadata", "event" => "agentFlowEvent", "event" => "token" events, and a final {"data" => "[DONE]", "event" => "end"} indicating the response is complete.

Intermittently, Flowise returns only the metadata and the {"data" => "[DONE]", "event" => "end"} events. No content is streamed back. The agent's response does exist in the https://cloud.flowiseai.com/v2/agentcanvas/{id} View Messages modal.

Request:

curl -L \
  --request POST \
  --url 'https://cloud.flowiseai.com/api/v1/prediction/{flow id}' \
  --header 'Authorization: Bearer {token}' \
  --header 'Content-Type: application/json' \
  --data '{
    "question": "hello",
    "streaming": true
  }'

Bugged Response:

message:
data:{"event":"metadata","data":{"chatId":"redacted","chatMessageId":"redacted","question":"hello","sessionId":"cfaf8d8d-0079-4d90-8299-857006742201"}}

message
data:{"event":"end","data":"[DONE]"}

Screenshot from the View Messages modal. The agent did respond, but the API did not return the content of the agent's response.

To Reproduce

curl -L \
  --request POST \
  --url 'https://cloud.flowiseai.com/api/v1/prediction/{flow id}' \
  --header 'Authorization: Bearer {token}' \
  --header 'Content-Type: application/json' \
  --data '{
    "question": "hello",
    "streaming": true
  }'

1. create an agent flow
2. make a post request with any question and streaming: true
3. repeat until you experience the bug

Expected behavior

Flowise should respond with the content of the agent's response. Below is the expected streamed response.

curl -L \
  --request POST \
  --url 'https://cloud.flowiseai.com/api/v1/prediction/{flow id}' \
  --header 'Authorization: Bearer {token}' \
  --header 'Content-Type: application/json' \
  --data '{
    "question": "hello",
    "streaming": true
  }'

message:
data:{"event":"agentFlowEvent","data":"INPROGRESS"}

message:
data:{"event":"nextAgentFlow","data":{"nodeId":"startAgentflow_0","nodeLabel":"Start","status":"INPROGRESS"}}

...

message:
data:{"event":"token","data":""}

message:
data:{"event":"token","data":""}

message:
data:{"event":"token","data":"#"}

message:
data:{"event":"token","data":" Hello\n\nHello"}

message:
data:{"event":"token","data":", a"}

message:
data:{"event":"token","data":" wor"}

message:
data:{"event":"token","data":"d that"}

message:
data:{"event":"token","data":" opens"}

message:
data:{"event":"token","data":" doors and bridges"}

message:
data:{"event":"token","data":" distant"}

message:
data:{"event":"token","data":" souls"}

message:
data:{"event":"token","data":" with"}

...

message:
data:{"event":"agentFlowEvent","data":"FINISHED"}

message:
data:{"event":"metadata","data":{"chatId": redacted, "chatMessageId": redacted,"question":"hello","sessionId": redacted}}

message
data:{"event":"end","data":"[DONE]"}

Screenshots

No response

Flow

No response

Use Method

Flowise Cloud

Flowise Version

No response

Operating System

None

Browser

None

Additional context

No response