REOPENS the agent path — but only because possession is now actually proven.
EPT verification (api/app/ept.py): ES256 against Eternitas's published key set
at /.well-known/eternitas-keys. algorithms=['ES256'] makes alg:none and
algorithm confusion unrepresentable rather than merely unlikely; issuer and exp
are enforced by the library; an unknown kid is refused.
Order is deliberate: signature FIRST, trust lookup second. These EPTs live ~365
days and carry rev/tru baked in at issuance, so a year-old 'rev: false' proves
nothing — revocation and band still come from a live lookup on every request.
Found while building it: real EPTs put the passport in . The old code read
/, which no genuine EPT carries — so real agents were
never recognised and ONLY forged tokens ever authenticated. The bypass was not
just a hole, it was the only thing that worked.
Throttle (api/app/throttle.py): BAND_MULTIPLIER and rate_*_per_day were defined
and read by nothing. Now enforced on repo.create and grant.create, counted
against agent_actions (one source of truth, not a private counter that drifts
from the audit log). Fails CLOSED — a limiter that fails open protects you until
the moment something is wrong. Untrusted band is 403 read-only, not 429, because
'slow down' would be a lie.
Tests: 14 behavioral, signing real ES256 tokens with a locally-generated key so
they exercise the crypto path with no network dependency — genuine tokens
accepted, and alg:none / foreign key / tampered payload / expired / wrong issuer
/ unknown kid / missing claims all refused. 74 green.
Co-Authored-By: Claude (Fable 5) <noreply@anthropic.com>
