discovery(rag): NeuralMeshRetriever never injected into RAGService._mesh_retriever in production — mesh_retriever_enabled flag permanently dead

[mrveiss]

Discovery

Issues #2059 and #2056 (Neural Mesh RAG Phase 3) are closed, but RAGService._mesh_retriever is never assigned in any non-test production code path. The mesh_retriever_enabled config flag defaults to False, so even if a NeuralMeshRetriever instance existed, it would not be used.

Evidence

rag_service.py:71 — field defaults to None and is never set outside tests:

self._mesh_retriever: Optional[Any] = None
# "set externally when Phase 3 is active" — but nothing sets it

rag_service.py:616 — guarded by two conditions, both always False in production:

if self.config.mesh_retriever_enabled and self._mesh_retriever is not None:
    return await self._run_mesh_retriever(query, max_results)

Grep result for _mesh_retriever = across all non-test Python files:

(empty — only test files assign it)

rag_config.py:61:

mesh_retriever_enabled: bool = False  # never flipped to True in production

The only non-test reference is services/neural_mesh/query_decomposer.py:102:

self.mesh_retriever = mesh_retriever  # different attribute, different class

Impact

• NeuralMeshRetriever service exists with tests but is never called in production
• The entire Neural Mesh RAG Phase 3 retrieval path is dead code
• RAG always falls through to AdvancedRAGOptimizer regardless of config
• mesh_retriever_enabled in RAGConfig / GET /api/rag/config response is misleading — turning it on does nothing

Fix Options

1. Wire it up: Find where NeuralMeshRetriever is instantiated and inject it into RAGService._mesh_retriever during app startup (in the relevant API startup/lifespan handler)
2. Remove it: If Phase 3 was abandoned, remove _mesh_retriever, _run_mesh_retriever(), mesh_retriever_enabled, and the mesh test file — clean dead code

Needs investigation to determine which path is correct.

Affected Files

• autobot-backend/services/rag_service.py — _mesh_retriever field + _run_mesh_retriever()
• autobot-backend/services/rag_config.py — mesh_retriever_enabled
• autobot-backend/services/neural_mesh/ — NeuralMeshRetriever implementation (check if still intended)

[mrveiss]

✅ Closed with proof of implementation

Commit: c10419c — fix(rag): remove dead NeuralMeshRetriever injection gate from RAGService (#4686)
PR: #4715 → merged to Dev_new_gui

Acceptance Criteria Met:

• ✅ _mesh_retriever field removed from RAGService
• ✅ _run_mesh_retriever() method removed
• ✅ mesh_retriever guard block in advanced_search() removed
• ✅ mesh_retriever_enabled removed from RAGConfig.to_dict()
• ✅ NeuralMeshRetriever class retained (has own tests)

Note: Recovered from git reflog after worktree was accidentally cleaned before push.