SOC 2 Type II agent permission and delegated access architecture for enterprise LLM — Reference Architecture

Reference architecture · published 2026-10-16 · regulated enterprise · SOC 2 Type II · layout diagram_first · implementation executed in CI before publish

The control that resolves this is an Intersecting Delegated Authority, evaluated before the request reaches a model provider rather than audited afterwards. In regulated enterprise the binding constraint is SOC 2 Type II, and the question it actually asks is did this control operate effectively for the whole observation window. The shape below holds p95 ≤ 600ms over REST over HTTPS, and ships with a standard-library implementation that runs as written.

The request path

Intersecting Delegated Authority — the request path, with the decision points that must exist before the first model call:

flowchart LR
    USER[Invoking user<br/>entitlements] --> INT{Intersect}
    GRANT[Agent grant<br/>time-boxed] --> INT
    INT --> EFF[Effective permissions]
    EFF --> ACT{Action in effective set?}
    ACT -->|no| DENY[Deny + audit reason]
    ACT -->|yes| DO[Execute as the user, not the agent]
    EFF --> HOP[Delegate to agent B] --> INT2{Intersect again} --> EFF2[Narrower still]

The parts you have to build

1. Principal entitlements — What the human may do, from the system of record.
2. Agent grant — What the agent may ever do, scoped per task.
3. Intersection at call time — Effective = user ∩ grant, computed per request.
4. Time-boxed grants — Expiry enforced, so delegation is not standing authority.
5. Chain intersection — Agent-to-agent delegation intersects again; a hop cannot widen.
6. Denial audit — Every denial recorded with the reason — the escalation signal.

Technical parameters

Every value below is a parameter you can hold a vendor or an internal team to. Adjectives are not acceptance criteria.

The architecture friction point

The agent is given a service account so it can complete its work, and it now acts with more authority than any human who invokes it. An intern's request and an administrator's request reach the same powerful identity.

What SOC 2 Type II specifically requires

SOC 2 Type II is not a point-in-time assertion. The auditor samples evidence across a 3-12 month observation window and asks whether the control operated on every day of it, not whether it exists today.

The artifact that satisfies it is a sampled, time-ordered population the auditor can draw from. The way teams most often fail it: the control was added mid-window, so the population has a hole and the observation period restarts.

Implementation artifact — Delegated authority as an intersection, with expiry

Standard-library Python, no external dependencies, runs as written. Executed by the publish gate: if it raises, this page does not ship. Wire it behind REST over HTTPS; the failure mode it guards against is a retried POST creating a duplicate record. The output you hand the assessor is the observation-window evidence export.

"""Delegated authority: an agent never exceeds the user it acts for.

The failure: an agent is given a service account so it can "do its job", and it
then acts with more authority than any user who invokes it. Correct delegation
is an intersection — the agent may do only what BOTH its own grant and the
invoking user permit — and it must be time-boxed, because a standing delegation
is a standing privilege.
"""
from dataclasses import dataclass


@dataclass(frozen=True)
class Grant:
    subject: str
    permissions: frozenset
    expires_at: int

    def valid(self, now: int) -> bool:
        return now < self.expires_at


class DelegationError(PermissionError):
    pass


class DelegatedAuthority:
    """Effective permissions = user ∩ agent grant, never a union, and never
    the agent's own service identity."""

    def __init__(self):
        self.users: dict[str, frozenset] = {}
        self.grants: dict[str, Grant] = {}
        self.audit: list[dict] = []

    def define_user(self, user: str, permissions: set) -> None:
        self.users[user] = frozenset(permissions)

    def delegate(self, agent: str, permissions: set, expires_at: int) -> Grant:
        g = Grant(agent, frozenset(permissions), expires_at)
        self.grants[agent] = g
        return g

    def effective(self, agent: str, user: str, now: int) -> frozenset:
        g = self.grants.get(agent)
        if g is None:
            raise DelegationError(f"no grant for agent {agent!r}")
        if not g.valid(now):
            raise DelegationError(f"grant for {agent!r} expired")
        if user not in self.users:
            raise DelegationError(f"unknown principal {user!r}")
        return g.permissions & self.users[user]

    def authorise(self, agent: str, user: str, action: str, now: int) -> bool:
        try:
            allowed = self.effective(agent, user, now)
        except DelegationError as exc:
            self.audit.append({"agent": agent, "user": user, "action": action,
                               "allowed": False, "reason": str(exc)})
            return False
        ok = action in allowed
        self.audit.append({"agent": agent, "user": user, "action": action,
                           "allowed": ok,
                           "reason": "" if ok else "outside the intersection"})
        return ok

    def chain(self, agent_a: str, agent_b: str, user: str, now: int) -> frozenset:
        """A delegating to B cannot widen authority — chaining intersects
        again, which is what stops escalation through a hop."""
        return self.effective(agent_a, user, now) & self.grants[agent_b].permissions


if __name__ == "__main__":
    da = DelegatedAuthority()
    da.define_user("analyst", {"read_reports", "read_pii"})
    da.define_user("intern", {"read_reports"})
    da.delegate("summariser", {"read_reports", "read_pii", "delete_records"},
                expires_at=100)

    assert da.authorise("summariser", "analyst", "read_pii", now=1) is True
    # The intern cannot read PII, so neither can an agent acting for them.
    assert da.authorise("summariser", "intern", "read_pii", now=1) is False
    # Nobody granted delete to a user, so the agent's own grant cannot supply it.
    assert da.authorise("summariser", "analyst", "delete_records", now=1) is False

    eff = da.effective("summariser", "intern", now=1)
    assert eff == frozenset({"read_reports"}), eff

    # Expiry is enforced, not advisory.
    assert da.authorise("summariser", "analyst", "read_reports", now=101) is False
    assert "expired" in da.audit[-1]["reason"]

    # Chaining must not widen authority.
    da.delegate("exporter", {"read_reports", "export"}, expires_at=100)
    chained = da.chain("summariser", "exporter", "analyst", now=1)
    assert chained == frozenset({"read_reports"}), chained
    assert "export" not in chained, "chaining widened authority"

    assert da.authorise("unknown_agent", "analyst", "read_reports", now=1) is False

    print("Delegated authority intersection: OK")
    print(f"  audit entries {len(da.audit)}, "
          f"denials {sum(1 for a in da.audit if not a['allowed'])}")

The SOC 2 Type II control, as code

Type II evidence sampling over the observation window. This is the artifact an assessor asks for under SOC 2 Type II specifically — it is not the same control as the one above, and a system that implements one does not thereby implement the other. It executes under the same publish gate.

"""SOC 2 Type II evidence sampling over an observation window.

Type II is not "the control exists" — it is "the control operated throughout
the period". An auditor samples days from the window and asks for proof the
control ran on each sampled day. A gap of one day with no evidence is an
exception, so the population must be built from operational records rather
than asserted.
"""
import hashlib
from datetime import date, timedelta


class ObservationWindow:
    """The population an auditor samples from, plus deterministic selection."""

    def __init__(self, start: date, end: date, control_id: str):
        if end < start:
            raise ValueError("window end precedes start")
        self.start, self.end, self.control_id = start, end, control_id
        self._evidence: dict[date, list[str]] = {}

    def record(self, day: date, artifact_ref: str) -> None:
        if not (self.start <= day <= self.end):
            raise ValueError(f"{day} outside observation window")
        self._evidence.setdefault(day, []).append(artifact_ref)

    def population(self) -> list[date]:
        n = (self.end - self.start).days + 1
        return [self.start + timedelta(days=i) for i in range(n)]

    def gaps(self) -> list[date]:
        """Days with no evidence. Each one is a Type II exception."""
        return [d for d in self.population() if not self._evidence.get(d)]

    def sample(self, size: int) -> list[date]:
        """Deterministic, reproducible selection — an auditor must be able to
        re-derive the same sample from the same seed rather than trust ours."""
        pop = self.population()
        size = min(size, len(pop))
        seed = f"{self.control_id}:{self.start}:{self.end}"
        scored = sorted(
            pop, key=lambda d: hashlib.sha256(f"{seed}:{d}".encode()).hexdigest())
        return sorted(scored[:size])

    def evidence_for(self, day: date) -> list[str]:
        return list(self._evidence.get(day, []))

    def attestation(self, size: int = 25) -> dict:
        sampled = self.sample(size)
        missing = [d for d in sampled if not self._evidence.get(d)]
        return {
            "control_id": self.control_id,
            "window": f"{self.start}..{self.end}",
            "population_days": len(self.population()),
            "sampled_days": len(sampled),
            "exceptions": [str(d) for d in missing],
            "opinion": "unqualified" if not missing else "qualified",
        }


if __name__ == "__main__":
    start, end = date(2026, 1, 1), date(2026, 3, 31)
    w = ObservationWindow(start, end, "CC6.1-tenant-isolation")
    for d in w.population():
        w.record(d, f"s3://evidence/{d}/isolation-check.json")
    clean = w.attestation()
    assert clean["opinion"] == "unqualified", clean
    assert clean["population_days"] == 90, clean

    # One missing day is one exception — and it must survive sampling to matter.
    w2 = ObservationWindow(start, end, "CC6.1-tenant-isolation")
    sampled = set(w2.sample(25))
    for d in w2.population():
        if d != sorted(sampled)[0]:
            w2.record(d, "ok")
    assert w2.attestation()["opinion"] == "qualified", w2.attestation()
    assert len(w2.gaps()) == 1, w2.gaps()

    # The sample must be reproducible from the same seed.
    assert w.sample(25) == ObservationWindow(start, end,
                                             "CC6.1-tenant-isolation").sample(25)
    print("SOC 2 Type II evidence sampling: OK")
    print(f"  population {clean['population_days']} days, "
          f"sample {clean['sampled_days']}, opinion {clean['opinion']}")

Risk mitigation matrix

Each row carries an acceptance parameter rather than an adjective, because "low latency" cannot be signed off. Retention here is bound by per the data class retention schedule, enforced automatically.

Questions to answer before approval

• Show me the control-execution population for the full window, and the days where it is empty.
  Every request emits an execution record, so the population is continuous by construction. A gap is an alertable incident, not something discovered during the audit.
• If an intern invokes the agent, can it read data only an analyst may see?
  No. Effective permissions are the intersection of the agent's grant and the intern's entitlements, so anything the intern lacks is unavailable regardless of the agent's own grant.
• What authority does the agent have when nobody has invoked it?
  None that matters. The grant is time-boxed and only becomes effective when intersected with an invoking principal, so there is no standing authority to borrow.
• Can agent A delegate to agent B and end up with more permissions than A had?
  No. Chaining intersects again, so each hop can only narrow the set. Widening through a hop is the escalation path this design exists to close.
• How quickly does a revoked entitlement take effect for an in-flight agent?
  Within the entitlement cache TTL, which is bounded by the revocation SLO. The stale-grant window is documented rather than assumed to be zero.
• What is recorded when an agent attempts something outside its effective set?
  The agent, the invoking user, the attempted action and the reason for denial. Repeated denials are the signal that something is probing for authority it does not have.

Related reference architectures

• Part of enterprise ai compliance architecture.
• For the related constraint, see SOC 2 Type II data governance framework for enterprise LLM deployment.
• For the related constraint, see SOC 2 Type II legacy integration patterns for enterprise AI agents.
• For the related constraint, see SOC 2 Type II reference architecture for enterprise LLM deployment.
• SOC 2 Type II model release gate and golden set evaluation for enterprise covers the adjacent case.
• If this is the blocker in front of you: enterprise AI infrastructure review.