fix: target agent component when updating chat flow system prompt

[Vchen7629]

Summary

Port of PR #1918 to target main, 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

• Bug Fixes

  • System prompt updates now reliably apply to the chat agent component and no longer depend on provider-specific selection logic.
  • Updates are simplified to always target the agent’s system_prompt, improving consistency.

• Tests

  • Added unit tests to verify the Agent node includes a system_prompt template and that update requests send the correct PATCH payload reflecting the new prompt.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Reviewing files that changed from the base of the PR and between a42d5e6 and 65cf3dc.

📒 Files selected for processing (1)

• tests/unit/test_langflow_agent_system_prompt.py

💤 Files with no reviewable changes (1)

• tests/unit/test_langflow_agent_system_prompt.py

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Walkthrough

The chat settings path now updates Langflow through the Agent node directly, without passing a provider. New tests verify the flow contains an Agent node with system_prompt and that patching updates that field.

Changes

System prompt update fix

Layer / File(s)	Summary
Simplify update_chat_flow_system_prompt targeting src/services/flows_service.py, src/api/settings/langflow_sync.py	update_chat_flow_system_prompt drops the provider argument and always updates the Agent node by AGENT_COMPONENT_DISPLAY_NAME; the caller now passes only system_prompt.
Add flow-loading test helpers tests/unit/test_langflow_agent_system_prompt.py	Adds helpers to load a flow JSON file and find nodes by display name, plus a test that flows/openrag_agent.json contains an Agent node with a system_prompt field.
Verify Agent node patching tests/unit/test_langflow_agent_system_prompt.py	Adds an async test that mocks Langflow GET/PATCH calls, invokes update_chat_flow_system_prompt, and asserts the Agent node’s template.system_prompt.value is updated.

Estimated code review effort: 2 (Simple) | ~10 minutes

Suggested labels: bug

Suggested reviewers: phact, edwinjosechittilappilly

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main fix: updating the chat flow system prompt on the Agent component.
Linked Issues check	✅ Passed	The changes target the Agent component where system_prompt lives, which matches the bug report and expected behavior in #1514.
Out of Scope Changes check	✅ Passed	The PR stays focused on the system-prompt target fix and related tests without unrelated code changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch agent-system-instruction-fix

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[coderabbitai]

🧹 Nitpick comments (1)

tests/unit/test_langflow_agent_system_prompt.py (1)

8-10: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Relative flow path depends on process cwd.

_load_flow resolves "flows/openrag_agent.json" relative to the current working directory rather than the repository root or test file location. If pytest is invoked from a different directory, both tests will fail with FileNotFoundError.

♻️ Suggested fix: resolve path relative to test file

+from pathlib import Path
+
+_REPO_ROOT = Path(__file__).resolve().parents[2]
+
+
 def _load_flow(flow_path: str) -> dict:
     """Load a Langflow flow JSON file from the given path."""
-    return json.loads(Path(flow_path).read_text(encoding="utf-8"))
+    return json.loads((_REPO_ROOT / flow_path).read_text(encoding="utf-8"))

Also applies to: 27-27, 43-43

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@tests/unit/test_langflow_agent_system_prompt.py` around lines 8 - 10, The
helper _load_flow currently reads the flow JSON using a path that depends on the
process working directory, so tests can break when pytest runs elsewhere. Update
_load_flow in test_langflow_agent_system_prompt.py to resolve the flow path
relative to the test file or repository root before calling Path.read_text, and
make sure the two tests that use openrag_agent.json keep using that resolved
path.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@tests/unit/test_langflow_agent_system_prompt.py`:
- Around line 8-10: The helper _load_flow currently reads the flow JSON using a
path that depends on the process working directory, so tests can break when
pytest runs elsewhere. Update _load_flow in test_langflow_agent_system_prompt.py
to resolve the flow path relative to the test file or repository root before
calling Path.read_text, and make sure the two tests that use openrag_agent.json
keep using that resolved path.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

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Run ID: f7fc59d0-5364-4b86-8f5e-e329b83a352b

📥 Commits

Reviewing files that changed from the base of the PR and between 4f104ec and e48a6dd.

📒 Files selected for processing (3)

• src/api/settings/langflow_sync.py
• src/services/flows_service.py
• tests/unit/test_langflow_agent_system_prompt.py