Stéphane Tailland
109 lines
4.4 KiB
Markdown
109 lines
4.4 KiB
Markdown
# Assistant — the orchestrating agent
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The single entry point for users. Understands a request, consults the
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specialists that can settle it, and composes one answer.
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**Framework:** LangGraph · **Mode:** conversational · **Client id:**
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`classic-models-agent-assistant`
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## It holds nothing, and that is enforced by the realm
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This is the component that sees raw user text, so it is the prompt-injection
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target. It has no MCP server, no domain scope, and no data of its own. That is
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not a convention in the prompt — it is what the realm grants:
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```
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OBTAINED classic-models-agent-catalogue-audience aud=[classic-models-agent-catalogue]
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refused mcp-catalog-audience → Invalid scopes
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refused mcp-sales-audience → Invalid scopes
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refused catalog-api-audience → Invalid scopes
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```
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An injection that succeeds against this agent finds no path to a domain,
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because there is none to find. Its two optional scopes are one specialist and
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the inference endpoint — inference is not a domain, and the agent has to reason.
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Adding a specialist is an entry in `specialists.py` plus an audience scope
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granted in the realm. Add the entry without the grant and every call to it fails
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at the token exchange with `Invalid scopes`, loudly, before any data moves.
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## The chain
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Four hops, `sub` unchanged throughout — which is what makes the end user's own
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roles apply at the far end:
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```
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1. user sub=pm-user azp=librechat aud=[…-agent-assistant]
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2. assistant→cat sub=pm-user azp=classic-models-agent-assistant aud=[…-agent-catalogue]
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3. cat→mcp sub=pm-user azp=classic-models-agent-catalogue aud=[mcp-catalog, token-exchange-broker]
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4. MCP call → 200
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```
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`azp` names the last agent in the chain, not the first. Keycloak accepts
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`actor_token` and emits no `act` claim, so an orchestrator's identity does not
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survive a second exchange — the delegation is visible in the traces, not in the
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token.
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## What it does with an answer
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A specialist returns an answer, never data. The orchestrator composes; it does
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not aggregate records it was not given.
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Two behaviours worth naming, both verified end to end:
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- **Out of remit → it says so.** Asked for a company-wide revenue figure, it
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reports that no specialist can settle it rather than answering from what the
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model knows. An invented answer is indistinguishable from one the estate gave.
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- **A held write is relayed verbatim.** Catalogue parks a proposed write in
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`input-required`; this agent passes that message through unchanged and stops.
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The user's `approve` comes back through the same conversation and reaches the
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specialist, which owns the decision. The orchestrator never approves on
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anyone's behalf.
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## The graph
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`plan → delegate → plan → …` until the model stops calling tools. One tool per
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specialist, described by what it *decides*. Delegations in the same step run
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concurrently — that is the point of fanning out at all — and are capped by
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`ASSISTANT_MAX_DELEGATIONS` (8), counted in calls rather than model turns,
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because one specialist consulted twice for the same question is the loop worth
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catching.
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The graph is rebuilt per turn: its tools carry the user's token, and a graph
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held across turns would be a token held across turns.
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## Running it
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```
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uv venv && uv pip install -e '.[dev]'
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ASSISTANT_CLIENT_SECRET=… ASSISTANT_CA_BUNDLE=… \
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ASSISTANT_URL_CATALOGUE=http://localhost:8099/ \
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python -m assistant_agent
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```
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`ASSISTANT_URL_<NAME>` overrides a specialist's address, for running outside the
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cluster against a port-forward. In the cluster nothing sets it.
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macOS resolves every `.local` name through mDNS before falling back to
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`/etc/hosts`, at a flat ~5s per host. `ASSISTANT_HTTP_TIMEOUT` defaults to 60s
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for that reason; in the cluster the names resolve instantly.
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## Deployment
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```
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gitea.sttlab.eu/stt/classic-models-agent-assistant:v0.2.1
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```
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`k8s/` is what runs, `dev/` is the Flux plumbing. Two manual applies close the
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loop once — the `agents` namespace and the `sttlab-ca` ConfigMap already exist,
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created by the catalogue agent's repo, and are deliberately not declared here so
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two Kustomizations do not fight over pruning them.
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```
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kubectl apply -f dev/gitrepository.yaml
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kubectl apply -f dev/bootstrap-kustomization.yaml
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```
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`replicas: 1` is a constraint: conversation history lives in the process, and a
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specialist's approval round trip passes back through here.
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