Fix: target agent component when updating chat flow system prompt

[Vchen7629]

Summary

Fixes #1514. update_chat_flow_system_prompt was targeting the LLM provider component (e.g. "Ollama", "WatsonX") instead of the Agent component where the system_prompt field lives. As a result, saving new agent instructions in OpenRAG settings never updates langflow

Changes:

• Updated update_chat_flow_system_prompt to use AGENT_COMPONENT_DISPLAY_NAME as the target component
• Added unit tests verifying the value is written to the Agent component in the flow

Summary by CodeRabbit

• Improvements

  • Simplified system prompt updates for Langflow flows.

• Tests

  • Added unit tests to verify system prompt functionality in Langflow flows.

[coderabbitai]

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Walkthrough

The PR simplifies system prompt updates for the Langflow Agent by removing provider-specific targeting. The FlowsService.update_chat_flow_system_prompt method removes its provider parameter and always targets the Agent node by fixed display name. The caller in langflow_sync.py is updated to stop deriving and passing the provider. New tests verify the Agent node structure and confirm the PATCH request correctly updates the system prompt field.

Changes

Agent System Prompt Update

Layer / File(s)	Summary
Service contract and implementation src/services/flows_service.py	update_chat_flow_system_prompt removes the provider parameter and always targets AGENT_COMPONENT_DISPLAY_NAME instead of deriving the target component ID from the provider.
Sync caller update src/api/settings/langflow_sync.py	_update_langflow_system_prompt no longer derives or passes llm_provider to the service method, calling update_chat_flow_system_prompt with only the system prompt.
Agent node verification tests tests/unit/test_langflow_agent_system_prompt.py	Test helpers load flow JSON and locate nodes by display name. Tests verify the Agent node contains a system_prompt field and that PATCH updates write the new prompt to template.system_prompt.value.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• langflow-ai/openrag#1742: Both PRs intersect on the Langflow openrag_agent.json Agent node/template, where this PR changes how system_prompt is PATCH-updated (and adds tests validating that path), while the retrieved PR substantially refreshes the embedded Agent component implementation in that same flow.

Suggested labels

bug

Suggested reviewers

• edwinjosechittilappilly

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: targeting the agent component instead of the LLM provider when updating the system prompt.
Linked Issues check	✅ Passed	The PR successfully addresses issue #1514 by fixing the system prompt update to target the Agent component instead of the LLM provider, which resolves the bug where agent instructions were not being applied to Langflow flows.
Out of Scope Changes check	✅ Passed	All changes are directly related to fixing the system prompt update mechanism and adding comprehensive tests; no out-of-scope modifications detected.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[Wallgau]

Great work!