when upgrading the version from dify 1.10.1-fix.1 to 1.15.0,the originally normal chatflow doesn't work error: base_url is required when creating a real Agent backend client

[yanpx169]

Self Checks

• I have searched for existing issues search for existing issues, including closed ones.
• I confirm that I am using English to submit this report (我已阅读并同意 Language Policy).
• [FOR CHINESE USERS] 请务必使用英文提交 Issue，否则会被关闭。谢谢！:)
• Please do not modify this template :) and fill in all the required fields.

1. Is this request related to a challenge you're experiencing? Tell me about your story.

I am deploying in an offline docker compose environment, when upgrading the version from dify 1.10.1-fix.1 to 1.15.0, an error occurred, please guide me on how to resolve this?
The same chatflow runs normally on dify1.10.1-fix.1 version

error info:
base_url is required when creating a real Agent backend client

docker compose logs :

worker-1            | 2026-06-30 11:23:37.172 INFO [Dummy-10572] [workflow_execute_task.py:463] 8fecea0eb0915b18b69cfb7d3597e516 - workflow_based_app_execution_task run with params: app_id='214005a9-8312-4d83-a4d3-f75f63b2f955' workflow_id='435007cf-ec66-4265-88cb-2a42b5f45083' tenant_id='a1fe8e85-0347-4842-bddb-fa10c969c212' app_mode=<AppMode.ADVANCED_CHAT: 'advanced-chat'> user=_Account(TYPE=<_UserType.ACCOUNT: 'account'>, user_id='b0330fbc-b344-4886-96eb-da4facd463f7') args={'files': [{'type': 'document', 'transfer_method': 'local_file', 'url': '', 'upload_file_id': '69689320-86a4-4841-ba5f-9f3bf8e41338'}], 'inputs': {}, 'query': '语音', 'conversation_id': ''} invoke_from=<InvokeFrom.DEBUGGER: 'debugger'> streaming=True call_depth=0 root_node_id=None workflow_run_id='62445bc6-ea5b-4cf1-9142-b101e278c3c8'
worker-1            | 2026-06-30 11:23:37.528 ERROR [Thread-10573 (_generate_worker)] [graph.py:165] 8fecea0eb0915b18b69cfb7d3597e516 - Failed to create node instance for node_id 1756347762231
worker-1            | Traceback (most recent call last):
worker-1            |   File "/app/api/.venv/lib/python3.12/site-packages/graphon/graph/graph.py", line 163, in _create_node_instances
worker-1            |     node_instance = node_factory.create_node(node_config)
worker-1            |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
worker-1            |   File "/app/api/core/workflow/node_factory.py", line 456, in create_node
worker-1            |     node_init_kwargs = node_init_kwargs_factories.get(node_type, lambda: {})()
worker-1            |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
worker-1            |   File "/app/api/core/workflow/node_factory.py", line 454, in <lambda>
worker-1            |     BuiltinNodeTypes.AGENT: lambda: self._build_agent_node_init_kwargs(node_class=node_class),
worker-1            |                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
worker-1            |   File "/app/api/core/workflow/node_factory.py", line 496, in _build_agent_node_init_kwargs
worker-1            |     "agent_backend_client": create_agent_backend_run_client(
worker-1            |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
worker-1            |   File "/app/api/clients/agent_backend/factory.py", line 21, in create_agent_backend_run_client
worker-1            |     raise ValueError("base_url is required when creating a real Agent backend client")
worker-1            | ValueError: base_url is required when creating a real Agent backend client
worker-1            | 2026-06-30 11:23:37.539 WARNING [Dummy-10572] [workflow_execute_task.py:446] 8fecea0eb0915b18b69cfb7d3597e516 - Workflow stream for run 62445bc6-ea5b-4cf1-9142-b101e278c3c8 ended without a terminal event; publishing fallback terminal event
nginx-1             | 10.92.109.60 - - [30/Jun/2026:11:23:37 +0000] "POST /console/api/apps/214005a9-8312-4d83-a4d3-f75f63b2f955/advanced-chat/workflows/draft/run HTTP/1.1" 200 1104 "http://10.231.147.37/app/214005a9-8312-4d83-a4d3-f75f63b2f955/workflow" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/149.0.0.0 Safari/537.36" "-"
worker-1            | 2026-06-30 11:23:37.603 INFO [Dummy-10572] [trace.py:128] 8fecea0eb0915b18b69cfb7d3597e516 - Task tasks.app_generate.workflow_execute_task.workflow_based_app_execution_task[16d01524-862c-490b-8ac3-81d15a207739] succeeded in 0.4316029427573085s: None
nginx-1             | 10.92.109.60 - - [30/Jun/2026:11:23:38 +0000] "GET /console/api/apps/214005a9-8312-4d83-a4d3-f75f63b2f955/workflows/draft/system-variables HTTP/1.1" 200 13 "http://10.231.147.37/app/214005a9-8312-4d83-a4d3-f75f63b2f955/workflow" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/149.0.0.0 Safari/537.36" "-"
nginx-1             | 10.92.109.60 - - [30/Jun/2026:11:23:38 +0000] "GET /console/api/apps/214005a9-8312-4d83-a4d3-f75f63b2f955/workflows/draft/variables?page=1&limit=100 HTTP/1.1" 200 453 "http://10.231.147.37/app/214005a9-8312-4d83-a4d3-f75f63b2f955/workflow" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/149.0.0.0 Safari/537.36" "-"
nginx-1             | 10.92.109.60 - - [30/Jun/2026:11:23:38 +0000] "GET /console/api/apps/214005a9-8312-4d83-a4d3-f75f63b2f955/workflows/draft/conversation-variables HTTP/1.1" 200 505 "http://10.231.147.37/app/214005a9-8312-4d83-a4d3-f75f63b2f955/workflow" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/149.0.0.0 Safari/537.36" "-"
api-1               | 2026-06-30 11:23:39.007 WARNING [Dummy-277] [version.py:61] 3d7127476238540597d3b1de1783f40a - Check update version error: timed out.
nginx-1             | 10.92.109.60 - - [30/Jun/2026:11:23:39 +0000] "GET /console/api/version?current_version=1.15.0 HTTP/1.1" 200 155 "http://10.231.147.37/app/214005a9-8312-4d83-a4d3-f75f63b2f955/workflow" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/149.0.0.0 Safari/537.36" "-"

I guess there might be an anomaly in the Agent node, but I don't know how to solve it?

2. Additional context or comments

No response

[dosubot[bot]]

This error occurs because Dify 1.15.0 introduced a new Agent backend microservice architecture that requires a AGENT_BACKEND_BASE_URL environment variable to be set. This variable is not included in the default docker-compose configuration, so upgrading from 1.10.x will trigger this error for any workflow containing an Agent node [1].

The factory function raises the error when base_url is None [2]:

if base_url is None:
    raise ValueError("base_url is required when creating a real Agent backend client")

To fix this, add the following environment variable to your api and worker services in your docker-compose .env file:

AGENT_BACKEND_BASE_URL=http://your-agent-backend-service:port

However, if you haven't deployed the separate agent backend service (which is a new component in 1.15.0), you can use the fake client as a workaround:

AGENT_BACKEND_USE_FAKE=true
AGENT_BACKEND_FAKE_SCENARIO=success

This provides an in-process mock that lets workflows run without the external service [3].

Important note: A maintainer has indicated that the Agent Roster feature is "not yet ready" in v1.15.0 [4], so you may want to check whether the Agent node in your workflow was intentionally added or if it appeared during migration. If your workflow didn't originally use an Agent node (only LLM nodes, etc.), something may have changed during the upgrade that's incorrectly invoking the agent backend path.

To reply, just mention @dosu.

---

Share context across your team and agents. Try Dosu.

[yanpx169]

The problem was solved after adding the following parameters in the.env file. Thank you for your guidance

AGENT_BACKEND_USE_FAKE=true
AGENT_BACKEND_FAKE_SCENARIO=success