# Multi-Tenant RAG / User & Role Scoping ## Technical Documentation — Vocero S2S v0.2.11+ > Date: 01/09/2026 > Scope: RAG Server-Side module (`speech_to_speech.RAG`) + Realtime WebSocket --- ## 1. Goal This change introduces a **scope isolation mechanism** into the Speech-to-Speech pipeline RAG, enabling different clients (logged-in users, roles) to receive **only the Knowledge Base chunks they are authorised to access**, without sharing private information across different sessions. Before this release the RAG was **single and global**: every WS session could see the entire shared KB. Now the retrieval can be filtered by: - **`user_id`** (single logical user) - **`roles`** (role list: agent, supervisor, backoffice…) - **`allowed_source_prefixes`** (custom prefixes on chunk `source` fields) - **Arbitrary metadata** (`metadata_filter` with exact match + `*_in` suffix for OR-list matches) Filters are applied **BEFORE** the cosine-similarity ranking (via NumPy boolean mask), so there is no accuracy loss or measurable performance penalty. --- ## 2. Comparison: old system vs new system | Criterion | Before (≤ v0.2.11 vanilla) | After (v0.2.11 + RAG scoping) | |---|---|---| | **Retrieval scope** | `_GLOBAL_RAG` singleton → everybody sees everything | Still a singleton, but `search()` applies a per-session scope mask | | **Data isolation** | ❌ None: different clients share private chunks (PII) | ✅ Each WS session declares `user_id`/`roles`/`prefixes`; only authorised chunks become ranking candidates | | **Memory usage** | 1 index, 1 embedding model | 1 index, 1 embedding model (no increase — filter is O(n) with a numpy mask) | | **KB population** | `source` is free-form, `metadata` is optional | `source` and `metadata` must follow a convention for filters (see §4) | | **How to declare scope** | ❌ Did not exist | ✅ **WebSocket query-string** at connection time | | **Test filters via HTTP** | ❌ `/v1/rag/search` only accepted query/top_k/threshold | ✅ `/v1/rag/search` now also accepts `allowed_source_prefixes` and `metadata_filter` | | **Hot-patch scope mid-session** | — | ⚠️ Possible only by mutating `runtime_config` directly (not exposed via `session.update` — see §9.1) | | **LLM hook** | `_inject_rag_context` called `search(query, top_k, threshold)` | Same hook, but additionally passes `allowed_prefixes` and `meta_filter` derived from `runtime_config` | | **Retrieval logging** | Log contained `count` + `sources_summary` | Log now also includes `scope_prefixes` and `scope_meta` for audit & debugging | --- ## 3. Codebase changes | File | Layer | Description | |---|---|---| | `src/speech_to_speech/RAG/retriever.py` | Search core | Extended `search(...)` signature with `allowed_source_prefixes` and `metadata_filter`. Applies a NumPy boolean mask before ranking. Supports `*_in` OR-list semantics on metadata. | | `src/speech_to_speech/RAG/router.py` | HTTP API | `SearchRequest` schema + `POST /v1/rag/search` endpoint now forward the new filters. | | `src/speech_to_speech/api/openai_realtime/runtime_config.py` | Session state | Added 3 fields on `RuntimeConfig`: `rag_user_id`, `rag_roles` (CSV coerced → list), `rag_allowed_source_prefixes` (CSV coerced → list). | | `src/speech_to_speech/api/openai_realtime/websocket_router.py` | WS claim | Inside `realtime_endpoint`, right after `register()`, scope parameters are read from the WS query-string and written into the session's `ConnState.runtime_config`. | | `src/speech_to_speech/LLM/base_openai_compatible_language_model.py` | LLM hook | `_inject_rag_context(...)` now receives `runtime_config`, builds `allowed_prefixes` (shared + roles + user + custom) and `metadata_filter` (`user_id`, `roles_in`), then forwards them to `search()`. The inject log now also reports the actual scope. | No files were removed; backward compatibility is preserved (all new parameters default to `None`, so clients that send no scope continue to see the **entire** KB exactly like before — "legacy" behaviour). --- ## 4. Conventions: how to tag chunks per user/role ### 4.1 `source` field convention (MANDATORY if you use prefix-based scoping) The leading part of `source` controls visibility through the `allowed_source_prefixes` filter. Use these standard prefixes: ``` users// # ← only user sees these chunks roles// # ← only users with see them shared/ # ← everyone sees them (same as public/) public/ # ← everyone sees them / # ← visible ONLY if explicitly passed into # rag_allowed_source_prefixes at WS connect ``` **Valid examples:** ``` users/123/user_preferences users/123/anamnesis_2026 roles/agent/procedure/open_ticket roles/supervisor/reports/monthly_kpis shared/general_intro public/helpdesk_hours kb_customer_alpha/contracts/clause_23 # ← needs prefixes=kb_customer_alpha/ in WS ``` ### 4.2 `metadata` convention (recommended — used by `metadata_filter`) | Key | Type | Semantics | |---|---|---| | `user_id` | `str`/`int` | Owner user identifier. The WS auto-filter uses EXACT match. | | `roles` | `list[str]` | Allowed roles. The WS auto-filter uses `roles_in: [...]` (OR-match: any match passes). | | `scopes` | `list[str]` | Optional (not used by the automatic filter — for custom business logic). | **Valid JSON examples:** ```json {"user_id": "123", "note": "sensitive data"} {"roles": ["agent", "supervisor"], "version": 3} ``` ### 4.3 The two filters don't exclude — they AND together `allowed_source_prefixes` and `metadata_filter` are combined with logical AND: a chunk passes only if **both** coincide. > 💡 Practical tip: stick to **only one mechanism** to keep things simple. > The default WS plumbing uses **both** for defence in depth — if you mess up > the prefix, the metadata filter still prevents leakage, and vice versa. --- ## 5. How to use it ### 5.1 Upload scoped chunks Use `/v1/rag/add/document` (auto-chunked) or `/v1/rag/add/chunks` (pre-chunked): ```bash # ---------- Single user 123 ---------- curl -X POST http://127.0.0.1:12345/v1/rag/add/document \ -H 'Content-Type: application/json' \ -d '{ "text": "User 123 preferences: coffee without sugar, nut allergy.", "source": "users/123/user_preferences", "metadata": {"user_id": "123"} }' # ---------- Visible to roles agent + supervisor ---------- curl -X POST http://127.0.0.1:12345/v1/rag/add/document \ -H 'Content-Type: application/json' \ -d '{ "text": "Procedure: to open a ticket, email support@example.com with the customer ID.", "source": "roles/agent/procedure/open_ticket", "metadata": {"roles": ["agent", "supervisor"]} }' # ---------- Visible to EVERYBODY ---------- curl -X POST http://127.0.0.1:12345/v1/rag/add/document \ -H 'Content-Type: application/json' \ -d '{ "text": "Helpdesk hours: Mon-Fri 9-18.", "source": "shared/helpdesk_hours", "metadata": {"scopes": ["public"]} }' # ---------- Custom scope (e.g. a whole customer tenant) ---------- curl -X POST http://127.0.0.1:12345/v1/rag/add/document \ -H 'Content-Type: application/json' \ -d '{ "text": "Alpha contract clause 23: 5% penalty for delay > 10 days.", "source": "kb_customer_alpha/contracts/clause_23", "metadata": {"customer": "alpha"} }' ``` ### 5.2 Connect the WebSocket declaring the scope Scope is populated **at WS connection time** via **query-string** (simpler and more standard than stuffing custom fields inside `session.update`). | WS param | Aliases | Example | Explanation | |---|---|---|---| | `user_id` | `rag_user_id` | `user_id=123` | User id. Produces prefix `users/123/` + filter `metadata.user_id=="123"`. | | `roles` | `rag_roles` | `roles=agent,supervisor` | CSV role list. Produces prefixes `roles/agent/`, `roles/supervisor/` + filter `metadata.roles ∩ [agent,supervisor] ≠ ∅`. | | `prefixes` | `allowed_source_prefixes` / `rag_allowed_source_prefixes` | `prefixes=shared/,kb_customer_alpha/` | CSV list of EXTRA custom prefixes to add on top of user/role/shared. | **Example WS URL — User 123, role agent, also needs kb_customer_alpha/** ``` ws://host:12345/v1/realtime?user_id=123&roles=agent&prefixes=kb_customer_alpha/ ``` What the system AUTOMATICALLY includes from this URL: ``` allowed_source_prefixes = [ "shared/", # always (builtin public) "public/", # always (builtin public) "roles/agent/", # from roles=agent "users/123/", # from user_id=123 "kb_customer_alpha/" # from prefixes= ] metadata_filter = { "roles_in": ["agent"], # from roles=agent "user_id": "123" # from user_id=123 } ``` Both filters are passed to `search()`. Result: retrieval can only pick from authorised chunks. ### 5.3 Test via HTTP /v1/rag/search To debug without opening a WS, hit the HTTP endpoint by explicitly sending the filters: ```bash # Search as if we were "user 123 with role agent" curl -sS -X POST http://127.0.0.1:12345/v1/rag/search \ -H 'Content-Type: application/json' \ -d '{ "query": "how do I open a ticket", "top_k": 5, "threshold": 0.05, "allowed_source_prefixes": ["shared/", "users/123/", "roles/agent/"], "metadata_filter": { "user_id": "123", "roles_in": ["agent", "supervisor"] } }' | python3 -m json.tool ``` Response (structure is unchanged — only the candidate chunk pool changes): ```json { "query": "how do I open a ticket", "count": 1, "results": [ { "text": "Procedure: to open a ticket, email support@example.com...", "source": "roles/agent/procedure/open_ticket", "chunk_index": 0, "score": 0.71, "metadata": {"roles": ["agent", "supervisor"]} } ] } ``` ### 5.4 Cleanup Delete every chunk for one user: ```bash curl -X POST http://127.0.0.1:12345/v1/rag/remove \ -H 'Content-Type: application/json' \ -d '{"source_prefix": "users/123/", "exact": false, "persist": true}' ``` Delete every chunk for one role: ```bash curl -X POST http://127.0.0.1:12345/v1/rag/remove \ -H 'Content-Type: application/json' \ -d '{"source_prefix": "roles/backoffice/", "exact": false, "persist": true}' ``` Reload the index after editing files inside `kb/`: ```bash curl -X POST http://127.0.0.1:12345/v1/rag/reload \ -H 'Content-Type: application/json' \ -d '{"force_rebuild": true}' ``` --- ## 6. Logging & Debugging What to look for in the PM2 pipeline logs: | Event | Level | You'll see | |---|---|---| | WS connection with scope | INFO | `RAG scope loaded from WS — user_id=X roles=Y prefixes=Z` | | Scope parsing failed | WARNING | `error applying RAG scope from query-string: ...` | | No chunk matched the scope | DEBUG | `no relevant chunks for turn=... scope_prefixes=... scope_meta=...` | | Retrieval OK (prompt injection) | INFO | `injected N chunks for turn=... (scope_prefixes=..., scope_meta=...)` | Handy one-liner to watch active scopes live: ```bash pm2 logs start_pipeline_rag --lines 200 | grep -i "RAG scope" ``` --- ## 7. Full end-to-end example **Scenario:** An external CRM opens 2 WS sessions: one for user 123 (private email stored in the RAG) and one for user 456. ```bash # 1) Seed the KB curl -X POST http://127.0.0.1:12345/v1/rag/upsert/document -H 'Content-Type: application/json' \ -d '{"text":"Account 123: mario.rossi@secretmail.example","source":"users/123/contacts","metadata":{"user_id":"123"}}' curl -X POST http://127.0.0.1:12345/v1/rag/upsert/document -H 'Content-Type: application/json' \ -d '{"text":"Account 456: lucia.bianchi@other.example","source":"users/456/contacts","metadata":{"user_id":"456"}}' curl -X POST http://127.0.0.1:12345/v1/rag/upsert/document -H 'Content-Type: application/json' \ -d '{"text":"Secretary office hours 9-18","source":"shared/hours"}' ``` ``` # 2) User 123 connects ws://127.0.0.1:12345/v1/realtime?user_id=123 ``` User 123 asks by voice: *"What is my email address?"* → the RAG returns theirs, **NOT** user 456's (filtered out). ``` # 3) User 456 connects ws://127.0.0.1:12345/v1/realtime?user_id=456 ``` Same question → the RAG returns user 456's email, never sees user 123's. Both users see `shared/hours` because it is force-included by default. --- ## 8. Backward compatibility - **With no WS params**: continues to behave exactly like before — no filter is applied, the entire KB is visible. Good for legacy scenarios. - **Existing `/v1/rag/*` APIs**: signatures unchanged; new fields are optional (`Optional[...]`) so pre-existing scripts **do not break**. - **On-disk persisted files**: no changes to `_dynamic.jsonl`, `_chunks.jsonl`, `_index.npz` — format is byte-identical. --- ## 9. Current limits & possible evolutions ### 9.1 Scope cannot be changed mid-session Today scope can only be fixed at `ws.accept()` via the query-string. Once the WS is connected you cannot update `user_id`/`roles` through `session.update` — you'd have to disconnect and reconnect. **Why:** `session.update` is typed as `RealtimeSessionCreateRequest` from the `openai-python` package, and we don't want to break SDK compatibility by attaching unofficial custom fields to it. **How to unlock it (future option):** add a custom event `session.scope_update` (non-standard) inside `RealtimeService.parse_client_event` that mutates `ConnState.runtime_config.rag_*`. ### 9.2 Soft (logical) isolation, not hard This is "Solution A": one shared index with a Python/NumPy vectorised filter. Sufficient for 90% of scenarios. It **does not** protect you from bugs that skip the filter (e.g. a future patch that forgets to thread it through). If you need process-level / index-level isolation (healthcare or finance data), you need "Solution B": a registry of multiple `RAGRetriever` instances, one per tenant, with separate NPZ indexes. ### 9.3 Multiple roles, but no permission hierarchy Today the `roles_in` filter is a flat OR. There is no concept of hierarchy (e.g. `supervisor` inherits every `agent` permission). **Workaround:** when writing `metadata.roles` list every role that should be allowed to read that chunk, not only the "base" one. E.g.: ```json {"roles": ["agent", "supervisor", "admin"]} # instead of just ["agent"] ``` ### 9.4 Embeddings cache The mask is recomputed on every `search()`. It is overwhelmingly fast up to `n < 500.000 chunks`; beyond that you could pre-compute one bitmask per discrete scope type and reuse it across sessions of the same kind. --- ## 10. Code references - Core filter: [RAGRetriever.search()](file:///home/azurian/speech-to-speech/src/speech_to_speech/RAG/retriever.py#L380-L489) - HTTP request schema: [SearchRequest](file:///home/azurian/speech-to-speech/src/speech_to_speech/RAG/router.py#L71-L82) - RuntimeConfig scope fields: [RuntimeConfig.rag_*](file:///home/azurian/speech-to-speech/src/speech_to_speech/api/openai_realtime/runtime_config.py#L40-L78) - WS query-string handler: [realtime_endpoint scope parsing](file:///home/azurian/speech-to-speech/src/speech_to_speech/api/openai_realtime/websocket_router.py#L626-L667) - LLM hook with injection: [_inject_rag_context](file:///home/azurian/speech-to-speech/src/speech_to_speech/LLM/base_openai_compatible_language_model.py#L292-L389)