Two bugs from review, the second in both agents because identity.py is a copy.
The exchanged-token cache grew for the life of the process. It is keyed on
(subject token, scope) and the subject token is minted fresh every turn, so
every turn added keys nothing would ever read again — and expiry was checked on
read but never collected. A slow leak that only shows in a pod up for days,
which is the worst way to find one.
It now drops expired entries first and evicts oldest beyond a bound. Expired
first on purpose: an expired entry is dead weight wherever it sits in the
ordering, so evicting by age alone would keep it while discarding a live one.
The docstring was wrong before the code was: it claimed the cache lasted one
turn. It never did. Corrected rather than quietly made true.
message_id reused the context id, which is the conversation — and a conversation
makes several calls to the same peer, relaying an approval being exactly that.
A peer treating the second call as a replay of the first would surface as a
stale answer rather than an error.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Entry point for the estate: understands a request, consults the specialists
that can settle it, composes one answer. LangGraph 1.2.11, a2a-sdk 1.1.2, both
current as of August 2026.
It holds no data, and the realm is what enforces that rather than the prompt.
classic-models-agent-assistant is granted two optional scopes — one per
specialist, plus the inference endpoint — and every domain audience it could
request comes back Invalid scopes. An injection that succeeds here finds no
path to a domain because there is none. "No scopes at all" was too absolute:
the agent has to reason, and inference is not a domain.
The two-hop token chain was the heaviest unproven thing in the design and it
holds: sub stays the end user through all four hops, so their own roles apply
at the far end and the MCP server filters tool discovery for the right human.
azp names the last agent, not the first — Keycloak accepts actor_token and
emits no act claim, so an orchestrator's identity survives only in the traces.
Verified end to end: a routed question answered from the specialist's data; a
question outside every remit refused rather than answered from memory; and a
write proposed through the orchestrator, held by the specialist in
input-required, relayed here unchanged, approved by the user through the same
conversation, and written. The orchestrator never owns that decision.
The graph is plan → delegate → plan, tools described by what a specialist
decides rather than what it holds, delegations in one step run concurrently and
capped at eight counted in calls. Rebuilt per turn, because its tools carry the
user's token.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Stéphane Tailland