TEN-WP-0002 T01-T03: service skeleton, domain model, storage layer

Python 3.12 + FastAPI, pyproject.toml + Makefile mirroring
qonto-assistant's exactly. src/tenant_engine/{domain,store,app,main}.py:

- domain.py: Tenant, CapabilityRole (PLTF/IAM/VEN/CUS), RoleGrant,
  PlanAssignment, create_role_grant() enforcing ADR-0014's invariants.
  Refinement made while implementing: platform_default grants are valid
  for trial-grouped tenants OR the reserved tenant:platform/tenant:coulomb
  tenants (their baseline roles were never purchased either) -- the task
  spec only named the trial case.
- store.py: TenantStore Protocol + InMemoryTenantStore, every mutation
  emits a DomainEvent per the boundary contract's Audit Correlation
  Contract.
- app.py/main.py: FastAPI factory + /health endpoint, verified live on
  127.0.0.1:8090.

29 tests passing, including non-exclusive role coexistence (CUS+VEN
simultaneously) and append-only revoke semantics.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Makefile

@@ -0,0 +1,33 @@
+VENV ?= .venv
+PYTHON ?= $(VENV)/bin/python
+PIP ?= $(PYTHON) -m pip
+PYTEST ?= $(PYTHON) -m pytest
+RUFF ?= $(VENV)/bin/ruff
+
+.PHONY: help install-dev test lint run
+
+help:
+	@echo "make install-dev  Create .venv and install runtime + dev dependencies"
+	@echo "make test         Run the test suite"
+	@echo "make lint         Run syntax and static checks"
+	@echo "make run          Start the local API on 127.0.0.1:8090"
+
+$(VENV)/bin/python:
+	python3 -m venv $(VENV)
+
+$(VENV)/.dev-installed: pyproject.toml $(VENV)/bin/python
+	$(PIP) install --upgrade pip
+	$(PIP) install -e ".[dev]"
+	@touch $(VENV)/.dev-installed
+
+install-dev: $(VENV)/.dev-installed
+
+test: $(VENV)/.dev-installed
+	$(PYTEST)
+
+lint: $(VENV)/.dev-installed
+	$(PYTHON) -m compileall src tests
+	$(RUFF) check src tests
+
+run: $(VENV)/.dev-installed
+	$(PYTHON) -m tenant_engine.main

pyproject.toml

@@ -0,0 +1,44 @@
+[build-system]
+requires = ["setuptools>=68", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "tenant-engine"
+version = "0.1.0"
+description = "Canonical owner of tenant-as-an-entity facts for NetKingdom: existence, onboarding grouping, capability roles, and plan/subscription assignment."
+readme = "README.md"
+requires-python = ">=3.12"
+license = { file = "LICENSE" }
+authors = [{ name = "Coulomb" }]
+dependencies = [
+    "fastapi>=0.115,<1.0",
+    "uvicorn[standard]>=0.30,<1.0",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest>=8.2,<9.0",
+    "httpx>=0.27,<1.0",
+    "ruff>=0.6,<1.0",
+]
+
+[project.scripts]
+tenant-engine = "tenant_engine.main:main"
+
+[tool.setuptools.packages.find]
+where = ["src"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+addopts = [
+    "--strict-markers",
+    "--disable-warnings",
+    "--tb=short",
+]
+
+[tool.ruff]
+line-length = 100
+target-version = "py312"
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "B"]

src/tenant_engine/__init__.py

@@ -0,0 +1 @@
+__version__ = "0.1.0"

src/tenant_engine/app.py

@@ -0,0 +1,19 @@
+from __future__ import annotations
+
+from fastapi import FastAPI
+
+from tenant_engine import __version__
+from tenant_engine.store import InMemoryTenantStore, TenantStore
+
+
+def create_app(*, store: TenantStore | None = None) -> FastAPI:
+    store = store or InMemoryTenantStore()
+
+    app = FastAPI(title="tenant-engine", version=__version__)
+    app.state.store = store
+
+    @app.get("/health")
+    async def health() -> dict[str, str]:
+        return {"status": "ok", "service": "tenant-engine", "version": __version__}
+
+    return app

src/tenant_engine/domain.py

@@ -0,0 +1,170 @@
+from __future__ import annotations
+
+from dataclasses import dataclass, replace
+from datetime import datetime
+from enum import Enum
+from typing import Literal
+
+# ADR-0013: onboarding-risk / entity-shape grouping. Orthogonal to
+# capability role (below) -- neither axis constrains the other except
+# through guardrail policy, which is a reserved, unimplemented concern.
+GROUPINGS = frozenset(
+    {
+        "trial",
+        "friendly",
+        "single",
+        "small",
+        "medium",
+        "large",
+        "enterprise",
+        "consumer",
+        "family",
+        "community",
+        "association",
+        "agentic",
+    }
+)
+
+# tenant:platform and tenant:coulomb predate the grouping taxonomy and stay
+# reserved, ungrouped identifiers (ADR-0013's Tenant Claim rationale).
+RESERVED_IDENTIFIERS = frozenset({"tenant:platform", "tenant:coulomb"})
+
+
+class InvalidTenantIdentifierError(ValueError):
+    """A tenant identifier does not match `tenant:<grouping>:<name>` or a reserved form."""
+
+
+class InvalidGrantError(ValueError):
+    """A role grant violates a domain invariant (ADR-0014)."""
+
+
+class CapabilityRole(str, Enum):
+    """ADR-0014: non-exclusive capability roles a tenant may hold."""
+
+    PLTF = "PLTF"
+    IAM = "IAM"
+    VEN = "VEN"
+    CUS = "CUS"
+
+
+GrantReason = Literal["plan_assignment", "manual_grant", "platform_default"]
+
+
+def parse_tenant_identifier(identifier: str) -> tuple[str | None, str]:
+    """Return (grouping, name). grouping is None only for reserved identifiers."""
+    if identifier in RESERVED_IDENTIFIERS:
+        return None, identifier.split(":", 1)[1]
+
+    parts = identifier.split(":")
+    if len(parts) != 3 or parts[0] != "tenant":
+        raise InvalidTenantIdentifierError(
+            f"Malformed tenant identifier: {identifier!r} (expected tenant:<grouping>:<name>)"
+        )
+    _, grouping, name = parts
+    if grouping not in GROUPINGS:
+        raise InvalidTenantIdentifierError(f"Unknown tenant grouping: {grouping!r}")
+    if not name:
+        raise InvalidTenantIdentifierError("Tenant name segment is empty")
+    return grouping, name
+
+
+@dataclass(frozen=True, slots=True)
+class Tenant:
+    tenant_id: str
+    identifier: str
+    grouping: str | None
+
+    @classmethod
+    def create(cls, *, tenant_id: str, identifier: str) -> "Tenant":
+        grouping, _name = parse_tenant_identifier(identifier)
+        return cls(tenant_id=tenant_id, identifier=identifier, grouping=grouping)
+
+    @property
+    def is_reserved(self) -> bool:
+        return self.grouping is None
+
+
+@dataclass(frozen=True, slots=True)
+class RoleGrant:
+    """Audited role grant record -- the Tenant Role & Plan Grant Contract shape.
+
+    Append-only: revocation produces a new record via `revoke()`, it never
+    deletes the original.
+    """
+
+    grant_id: str
+    tenant_id: str
+    role: CapabilityRole
+    grant_reason: GrantReason
+    plan_id: str | None
+    granted_by: str
+    granted_at: datetime
+    correlation_id: str
+    revoked_at: datetime | None = None
+
+    @property
+    def active(self) -> bool:
+        return self.revoked_at is None
+
+    def revoke(self, *, at: datetime) -> "RoleGrant":
+        if self.revoked_at is not None:
+            raise InvalidGrantError(f"Grant {self.grant_id!r} is already revoked")
+        return replace(self, revoked_at=at)
+
+
+@dataclass(frozen=True, slots=True)
+class PlanAssignment:
+    """A tenant's current plan, referenced by id only -- never resolved or
+
+    duplicated locally. Plan term definitions belong to adaptive-pricing.
+    """
+
+    tenant_id: str
+    plan_id: str
+    assigned_at: datetime
+
+
+def create_role_grant(
+    *,
+    tenant: Tenant,
+    grant_id: str,
+    role: CapabilityRole,
+    grant_reason: GrantReason,
+    plan_id: str | None,
+    granted_by: str,
+    correlation_id: str,
+    granted_at: datetime,
+) -> RoleGrant:
+    """Construct a RoleGrant, enforcing ADR-0014's domain invariants.
+
+    - `plan_assignment` grants always require a `plan_id`.
+    - `platform_default` grants never carry a `plan_id`, and are only valid
+      for `trial`-grouped tenants (ADR-0014: trial may hold any role,
+      unrestricted, for showcase purposes) or the reserved, ungrouped
+      `tenant:platform`/`tenant:coulomb` tenants (their baseline roles were
+      never purchased either).
+    - `manual_grant` carries no grouping restriction and an optional
+      `plan_id`.
+    """
+    if grant_reason == "plan_assignment" and plan_id is None:
+        raise InvalidGrantError("plan_assignment grants require a plan_id")
+
+    if grant_reason == "platform_default":
+        if plan_id is not None:
+            raise InvalidGrantError("platform_default grants must not carry a plan_id")
+        if tenant.grouping not in (None, "trial"):
+            raise InvalidGrantError(
+                "platform_default is only valid for trial-grouped or reserved tenants, "
+                f"got grouping={tenant.grouping!r}"
+            )
+
+    return RoleGrant(
+        grant_id=grant_id,
+        tenant_id=tenant.tenant_id,
+        role=role,
+        grant_reason=grant_reason,
+        plan_id=plan_id,
+        granted_by=granted_by,
+        granted_at=granted_at,
+        correlation_id=correlation_id,
+    )

src/tenant_engine/main.py

@@ -0,0 +1,13 @@
+from __future__ import annotations
+
+import uvicorn
+
+from tenant_engine.app import create_app
+
+
+def main() -> None:
+    uvicorn.run(create_app(), host="127.0.0.1", port=8090)
+
+
+if __name__ == "__main__":
+    main()

src/tenant_engine/store.py

@@ -0,0 +1,120 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from datetime import UTC, datetime
+from typing import Any, Protocol
+
+from tenant_engine.domain import CapabilityRole, PlanAssignment, RoleGrant, Tenant
+
+
+class TenantNotFoundError(KeyError):
+    pass
+
+
+class TenantAlreadyExistsError(ValueError):
+    pass
+
+
+class GrantNotFoundError(KeyError):
+    pass
+
+
+@dataclass(frozen=True, slots=True)
+class DomainEvent:
+    """Boundary contract's Audit Correlation Contract, in event form."""
+
+    event_type: str
+    tenant_id: str
+    at: datetime
+    payload: dict[str, Any]
+
+
+class TenantStore(Protocol):
+    """Swappable persistence seam -- domain/ and api/ depend on this, not a backend."""
+
+    def create_tenant(self, tenant: Tenant) -> None: ...
+
+    def get_tenant(self, tenant_id: str) -> Tenant: ...
+
+    def grant_role(self, grant: RoleGrant) -> None: ...
+
+    def revoke_role(self, *, tenant_id: str, grant_id: str, at: datetime) -> RoleGrant: ...
+
+    def active_roles(self, tenant_id: str) -> frozenset[CapabilityRole]: ...
+
+    def assign_plan(self, assignment: PlanAssignment) -> None: ...
+
+    def events(self) -> list[DomainEvent]: ...
+
+
+class InMemoryTenantStore:
+    def __init__(self) -> None:
+        self._tenants: dict[str, Tenant] = {}
+        self._grants: dict[str, dict[str, RoleGrant]] = {}
+        self._plans: dict[str, PlanAssignment] = {}
+        self._events: list[DomainEvent] = []
+
+    def create_tenant(self, tenant: Tenant) -> None:
+        if tenant.tenant_id in self._tenants:
+            raise TenantAlreadyExistsError(tenant.tenant_id)
+        self._tenants[tenant.tenant_id] = tenant
+        self._grants[tenant.tenant_id] = {}
+        self._emit(
+            "tenant_created",
+            tenant.tenant_id,
+            {"identifier": tenant.identifier, "grouping": tenant.grouping},
+        )
+
+    def get_tenant(self, tenant_id: str) -> Tenant:
+        try:
+            return self._tenants[tenant_id]
+        except KeyError:
+            raise TenantNotFoundError(tenant_id) from None
+
+    def grant_role(self, grant: RoleGrant) -> None:
+        self.get_tenant(grant.tenant_id)
+        self._grants[grant.tenant_id][grant.grant_id] = grant
+        self._emit(
+            "role_granted",
+            grant.tenant_id,
+            {
+                "grant_id": grant.grant_id,
+                "role": grant.role.value,
+                "grant_reason": grant.grant_reason,
+                "correlation_id": grant.correlation_id,
+            },
+        )
+
+    def revoke_role(self, *, tenant_id: str, grant_id: str, at: datetime) -> RoleGrant:
+        self.get_tenant(tenant_id)
+        try:
+            grant = self._grants[tenant_id][grant_id]
+        except KeyError:
+            raise GrantNotFoundError(grant_id) from None
+        revoked = grant.revoke(at=at)
+        self._grants[tenant_id][grant_id] = revoked
+        self._emit(
+            "role_revoked",
+            tenant_id,
+            {"grant_id": grant_id, "role": revoked.role.value},
+        )
+        return revoked
+
+    def active_roles(self, tenant_id: str) -> frozenset[CapabilityRole]:
+        self.get_tenant(tenant_id)
+        return frozenset(
+            grant.role for grant in self._grants.get(tenant_id, {}).values() if grant.active
+        )
+
+    def assign_plan(self, assignment: PlanAssignment) -> None:
+        self.get_tenant(assignment.tenant_id)
+        self._plans[assignment.tenant_id] = assignment
+        self._emit("plan_assigned", assignment.tenant_id, {"plan_id": assignment.plan_id})
+
+    def events(self) -> list[DomainEvent]:
+        return list(self._events)
+
+    def _emit(self, event_type: str, tenant_id: str, payload: dict[str, Any]) -> None:
+        self._events.append(
+            DomainEvent(event_type=event_type, tenant_id=tenant_id, at=datetime.now(UTC), payload=payload)
+        )

tests/test_app.py

@@ -0,0 +1,13 @@
+from fastapi.testclient import TestClient
+
+from tenant_engine.app import create_app
+
+
+def test_health_endpoint() -> None:
+    client = TestClient(create_app())
+    response = client.get("/health")
+
+    assert response.status_code == 200
+    body = response.json()
+    assert body["status"] == "ok"
+    assert body["service"] == "tenant-engine"

tests/test_domain.py

@@ -0,0 +1,206 @@
+from datetime import UTC, datetime
+
+import pytest
+
+from tenant_engine.domain import (
+    CapabilityRole,
+    InvalidGrantError,
+    InvalidTenantIdentifierError,
+    Tenant,
+    create_role_grant,
+    parse_tenant_identifier,
+)
+
+
+def test_parse_tenant_identifier_reserved_platform() -> None:
+    grouping, name = parse_tenant_identifier("tenant:platform")
+    assert grouping is None
+    assert name == "platform"
+
+
+def test_parse_tenant_identifier_reserved_coulomb() -> None:
+    grouping, name = parse_tenant_identifier("tenant:coulomb")
+    assert grouping is None
+    assert name == "coulomb"
+
+
+def test_parse_tenant_identifier_grouped() -> None:
+    grouping, name = parse_tenant_identifier("tenant:friendly:binky")
+    assert grouping == "friendly"
+    assert name == "binky"
+
+
+@pytest.mark.parametrize(
+    "identifier",
+    [
+        "tenant:unknown-grouping:binky",
+        "tenant:friendly",
+        "tenant:friendly:",
+        "not-a-tenant:friendly:binky",
+        "friendly:binky",
+    ],
+)
+def test_parse_tenant_identifier_rejects_invalid_shapes(identifier: str) -> None:
+    with pytest.raises(InvalidTenantIdentifierError):
+        parse_tenant_identifier(identifier)
+
+
+def test_tenant_create_from_identifier() -> None:
+    tenant = Tenant.create(tenant_id="t-1", identifier="tenant:friendly:binky")
+    assert tenant.grouping == "friendly"
+    assert tenant.is_reserved is False
+
+
+def test_tenant_create_reserved_has_no_grouping() -> None:
+    tenant = Tenant.create(tenant_id="t-platform", identifier="tenant:platform")
+    assert tenant.grouping is None
+    assert tenant.is_reserved is True
+
+
+def _tenant(*, grouping: str | None, identifier: str | None = None) -> Tenant:
+    if identifier is None:
+        identifier = f"tenant:{grouping}:acme" if grouping else "tenant:platform"
+    return Tenant.create(tenant_id="t-1", identifier=identifier)
+
+
+def test_plan_assignment_grant_requires_plan_id() -> None:
+    tenant = _tenant(grouping="friendly")
+    with pytest.raises(InvalidGrantError):
+        create_role_grant(
+            tenant=tenant,
+            grant_id="g-1",
+            role=CapabilityRole.IAM,
+            grant_reason="plan_assignment",
+            plan_id=None,
+            granted_by="ops",
+            correlation_id="corr-1",
+            granted_at=datetime.now(UTC),
+        )
+
+
+def test_plan_assignment_grant_with_plan_id_succeeds() -> None:
+    tenant = _tenant(grouping="friendly")
+    grant = create_role_grant(
+        tenant=tenant,
+        grant_id="g-1",
+        role=CapabilityRole.IAM,
+        grant_reason="plan_assignment",
+        plan_id="plan-iam-dedicated",
+        granted_by="ops",
+        correlation_id="corr-1",
+        granted_at=datetime.now(UTC),
+    )
+    assert grant.active is True
+    assert grant.plan_id == "plan-iam-dedicated"
+
+
+def test_platform_default_allowed_for_trial_tenant_without_plan() -> None:
+    tenant = _tenant(grouping="trial")
+    grant = create_role_grant(
+        tenant=tenant,
+        grant_id="g-1",
+        role=CapabilityRole.VEN,
+        grant_reason="platform_default",
+        plan_id=None,
+        granted_by="platform",
+        correlation_id="corr-1",
+        granted_at=datetime.now(UTC),
+    )
+    assert grant.grant_reason == "platform_default"
+    assert grant.plan_id is None
+
+
+def test_platform_default_allowed_for_reserved_tenant() -> None:
+    tenant = _tenant(grouping=None, identifier="tenant:platform")
+    grant = create_role_grant(
+        tenant=tenant,
+        grant_id="g-1",
+        role=CapabilityRole.PLTF,
+        grant_reason="platform_default",
+        plan_id=None,
+        granted_by="platform",
+        correlation_id="corr-1",
+        granted_at=datetime.now(UTC),
+    )
+    assert grant.role is CapabilityRole.PLTF
+
+
+def test_platform_default_rejected_for_non_trial_grouped_tenant() -> None:
+    tenant = _tenant(grouping="enterprise")
+    with pytest.raises(InvalidGrantError):
+        create_role_grant(
+            tenant=tenant,
+            grant_id="g-1",
+            role=CapabilityRole.VEN,
+            grant_reason="platform_default",
+            plan_id=None,
+            granted_by="platform",
+            correlation_id="corr-1",
+            granted_at=datetime.now(UTC),
+        )
+
+
+def test_platform_default_rejected_when_plan_id_present() -> None:
+    tenant = _tenant(grouping="trial")
+    with pytest.raises(InvalidGrantError):
+        create_role_grant(
+            tenant=tenant,
+            grant_id="g-1",
+            role=CapabilityRole.VEN,
+            grant_reason="platform_default",
+            plan_id="plan-x",
+            granted_by="platform",
+            correlation_id="corr-1",
+            granted_at=datetime.now(UTC),
+        )
+
+
+def test_manual_grant_allows_missing_plan_id_for_any_grouping() -> None:
+    tenant = _tenant(grouping="enterprise")
+    grant = create_role_grant(
+        tenant=tenant,
+        grant_id="g-1",
+        role=CapabilityRole.CUS,
+        grant_reason="manual_grant",
+        plan_id=None,
+        granted_by="ops",
+        correlation_id="corr-1",
+        granted_at=datetime.now(UTC),
+    )
+    assert grant.grant_reason == "manual_grant"
+
+
+def test_grant_revoke_is_append_only() -> None:
+    tenant = _tenant(grouping="friendly")
+    grant = create_role_grant(
+        tenant=tenant,
+        grant_id="g-1",
+        role=CapabilityRole.CUS,
+        grant_reason="manual_grant",
+        plan_id=None,
+        granted_by="ops",
+        correlation_id="corr-1",
+        granted_at=datetime.now(UTC),
+    )
+    revoked = grant.revoke(at=datetime.now(UTC))
+
+    assert grant.revoked_at is None, "original record must be untouched"
+    assert revoked.revoked_at is not None
+    assert revoked.grant_id == grant.grant_id
+
+
+def test_revoking_twice_raises() -> None:
+    tenant = _tenant(grouping="friendly")
+    grant = create_role_grant(
+        tenant=tenant,
+        grant_id="g-1",
+        role=CapabilityRole.CUS,
+        grant_reason="manual_grant",
+        plan_id=None,
+        granted_by="ops",
+        correlation_id="corr-1",
+        granted_at=datetime.now(UTC),
+    ).revoke(at=datetime.now(UTC))
+
+    with pytest.raises(InvalidGrantError):
+        grant.revoke(at=datetime.now(UTC))

tests/test_store.py

@@ -0,0 +1,124 @@
+from datetime import UTC, datetime
+
+import pytest
+
+from tenant_engine.domain import CapabilityRole, PlanAssignment, Tenant, create_role_grant
+from tenant_engine.store import (
+    GrantNotFoundError,
+    InMemoryTenantStore,
+    TenantAlreadyExistsError,
+    TenantNotFoundError,
+)
+
+
+def _store_with_tenant(*, grouping: str = "friendly", name: str = "binky") -> tuple[InMemoryTenantStore, Tenant]:
+    store = InMemoryTenantStore()
+    tenant = Tenant.create(tenant_id=f"t-{name}", identifier=f"tenant:{grouping}:{name}")
+    store.create_tenant(tenant)
+    return store, tenant
+
+
+def test_create_and_get_tenant() -> None:
+    store, tenant = _store_with_tenant()
+    assert store.get_tenant(tenant.tenant_id) == tenant
+
+
+def test_create_duplicate_tenant_raises() -> None:
+    store, tenant = _store_with_tenant()
+    with pytest.raises(TenantAlreadyExistsError):
+        store.create_tenant(tenant)
+
+
+def test_get_unknown_tenant_raises() -> None:
+    store = InMemoryTenantStore()
+    with pytest.raises(TenantNotFoundError):
+        store.get_tenant("does-not-exist")
+
+
+def test_grant_and_active_roles() -> None:
+    store, tenant = _store_with_tenant()
+    grant = create_role_grant(
+        tenant=tenant,
+        grant_id="g-1",
+        role=CapabilityRole.CUS,
+        grant_reason="manual_grant",
+        plan_id=None,
+        granted_by="ops",
+        correlation_id="corr-1",
+        granted_at=datetime.now(UTC),
+    )
+    store.grant_role(grant)
+
+    assert store.active_roles(tenant.tenant_id) == frozenset({CapabilityRole.CUS})
+
+
+def test_revoke_removes_role_from_active_set_but_keeps_record() -> None:
+    store, tenant = _store_with_tenant()
+    grant = create_role_grant(
+        tenant=tenant,
+        grant_id="g-1",
+        role=CapabilityRole.VEN,
+        grant_reason="manual_grant",
+        plan_id=None,
+        granted_by="ops",
+        correlation_id="corr-1",
+        granted_at=datetime.now(UTC),
+    )
+    store.grant_role(grant)
+    revoked = store.revoke_role(tenant_id=tenant.tenant_id, grant_id="g-1", at=datetime.now(UTC))
+
+    assert revoked.revoked_at is not None
+    assert store.active_roles(tenant.tenant_id) == frozenset()
+
+
+def test_revoke_unknown_grant_raises() -> None:
+    store, tenant = _store_with_tenant()
+    with pytest.raises(GrantNotFoundError):
+        store.revoke_role(tenant_id=tenant.tenant_id, grant_id="missing", at=datetime.now(UTC))
+
+
+def test_non_exclusive_roles_coexist() -> None:
+    store, tenant = _store_with_tenant()
+    for role in (CapabilityRole.CUS, CapabilityRole.VEN):
+        store.grant_role(
+            create_role_grant(
+                tenant=tenant,
+                grant_id=f"g-{role.value}",
+                role=role,
+                grant_reason="manual_grant",
+                plan_id=None,
+                granted_by="ops",
+                correlation_id="corr-1",
+                granted_at=datetime.now(UTC),
+            )
+        )
+
+    assert store.active_roles(tenant.tenant_id) == frozenset({CapabilityRole.CUS, CapabilityRole.VEN})
+
+
+def test_assign_plan() -> None:
+    store, tenant = _store_with_tenant()
+    store.assign_plan(PlanAssignment(tenant_id=tenant.tenant_id, plan_id="plan-x", assigned_at=datetime.now(UTC)))
+
+    events = store.events()
+    assert any(event.event_type == "plan_assigned" and event.payload["plan_id"] == "plan-x" for event in events)
+
+
+def test_every_mutation_emits_an_event() -> None:
+    store, tenant = _store_with_tenant()
+    grant = create_role_grant(
+        tenant=tenant,
+        grant_id="g-1",
+        role=CapabilityRole.CUS,
+        grant_reason="manual_grant",
+        plan_id=None,
+        granted_by="ops",
+        correlation_id="corr-1",
+        granted_at=datetime.now(UTC),
+    )
+    store.grant_role(grant)
+    store.revoke_role(tenant_id=tenant.tenant_id, grant_id="g-1", at=datetime.now(UTC))
+    store.assign_plan(PlanAssignment(tenant_id=tenant.tenant_id, plan_id="plan-x", assigned_at=datetime.now(UTC)))
+
+    event_types = [event.event_type for event in store.events()]
+    assert event_types == ["tenant_created", "role_granted", "role_revoked", "plan_assigned"]

workplans/TEN-WP-0002-domain-model-and-scaffold.md

@@ -34,7 +34,7 @@ enforcement.
 
 ```task
 id: TEN-WP-0002-T01
-status: todo
+status: done
 priority: high
 state_hub_task_id: "d22b0ce8-3f25-4c8d-b54f-ba44c65159c1"
 ```
@@ -47,11 +47,19 @@ routers), from day one — not refactored in later.
 Done when: `make test` runs an empty/smoke suite; `make run` starts a bare
 FastAPI app with a `/health` endpoint.
 
+**Done 2026-07-23:** `pyproject.toml` + `Makefile` land, mirroring
+`qonto-assistant`'s exactly (`install-dev`/`test`/`lint`/`run`).
+`src/tenant_engine/{domain,store,app,main}.py` scaffolded per the planned
+layering (`domain.py` pure, `store.py` the persistence seam, `app.py` the
+FastAPI factory). Verified live: `python -m tenant_engine.main` starts on
+`127.0.0.1:8090`, `GET /health` returns
+`{"status": "ok", "service": "tenant-engine", "version": "0.1.0"}`.
+
 ## Task: Domain model — tenant, grouping, capability role, plan grant
 
 ```task
 id: TEN-WP-0002-T02
-status: todo
+status: done
 priority: high
 state_hub_task_id: "cfceea30-f383-4781-a7e4-226653aafca9"
 ```
@@ -84,11 +92,23 @@ Validation rules encoded as domain invariants, not just API-layer checks:
 Done when: unit tests cover valid/invalid grouping values, the trial/
 no-plan-required exception, and grant/revoke as append-only operations.
 
+**Done 2026-07-23:** `domain.py` implements `Tenant`, `CapabilityRole`,
+`RoleGrant`, `PlanAssignment`, and `create_role_grant()` exactly as
+specified. One refinement made while implementing, not pre-specified in the
+task text: `platform_default` is valid for `trial`-grouped tenants **or**
+the reserved, ungrouped `tenant:platform`/`tenant:coulomb` tenants (their
+baseline roles were never purchased either) — the task only mentioned the
+`trial` case. Also enforced `platform_default` grants must not carry a
+`plan_id` (implied by "no `plan_id`" in the task text, made an explicit
+invariant). `tests/test_domain.py` covers all listed cases plus the
+reserved-tenant extension and double-revoke rejection. `pytest` →
+29 passed (whole-repo total, includes T03's tests below).
+
 ## Task: Storage layer
 
 ```task
 id: TEN-WP-0002-T03
-status: todo
+status: done
 priority: high
 state_hub_task_id: "ade9374a-ed26-45da-a424-a0d21effe520"
 ```
@@ -103,6 +123,14 @@ Contract — the event bus itself can be a simple in-process list for now.
 Done when: unit tests cover create/read/grant/revoke/assign-plan through the
 store interface, plus event emission for each mutation.
 
+**Done 2026-07-23:** `store.py`'s `TenantStore` Protocol +
+`InMemoryTenantStore` implement create/get/grant/revoke/active_roles/
+assign_plan, each emitting a `DomainEvent`. `tests/test_store.py` covers
+the full lifecycle, non-exclusive role coexistence (`CUS` + `VEN`
+simultaneously, proving ADR-0014's non-exclusivity isn't just a comment),
+revoke-keeps-record-but-clears-active-set, and asserts the exact event
+sequence for a full mutation chain. `python -m compileall src tests` clean.
+
 ## Task: Cache-read API (for key-cape)
 
 ```task