diff --git a/contract/machines.go b/contract/machines.go
index 4c93d35..a19f30a 100644
--- a/contract/machines.go
+++ b/contract/machines.go
@@ -1,7 +1,23 @@
 package host
 
+import "time"
+
+type Machine struct {
+	ID             MachineID    `json:"id"`
+	Artifact       ArtifactRef  `json:"artifact"`
+	SystemVolumeID VolumeID     `json:"system_volume_id,omitempty"`
+	UserVolumeIDs  []VolumeID   `json:"user_volume_ids,omitempty"`
+	Phase          MachinePhase `json:"phase"`
+	RuntimeHost    string       `json:"runtime_host,omitempty"`
+	Error          string       `json:"error,omitempty"`
+	CreatedAt      time.Time    `json:"created_at"`
+	StartedAt      *time.Time   `json:"started_at,omitempty"`
+}
+
 type CreateMachineRequest struct {
-	MachineID MachineID `json:"machine_id"`
+	MachineID     MachineID   `json:"machine_id"`
+	Artifact      ArtifactRef `json:"artifact"`
+	UserVolumeIDs []VolumeID  `json:"user_volume_ids,omitempty"`
 }
 
 type CreateMachineResponse struct {
diff --git a/contract/storage.go b/contract/storage.go
new file mode 100644
index 0000000..59325ff
--- /dev/null
+++ b/contract/storage.go
@@ -0,0 +1,15 @@
+package host
+
+import "time"
+
+type ArtifactRef struct {
+	ID      ArtifactID      `json:"id"`
+	Version ArtifactVersion `json:"version"`
+}
+
+type Volume struct {
+	ID                VolumeID   `json:"id"`
+	Kind              VolumeKind `json:"kind"`
+	AttachedMachineID *MachineID `json:"attached_machine_id,omitempty"`
+	CreatedAt         time.Time  `json:"created_at"`
+}
diff --git a/contract/types.go b/contract/types.go
index 9470317..fa5a379 100644
--- a/contract/types.go
+++ b/contract/types.go
@@ -1,6 +1,8 @@
 package host
 
-import "time"
+type ArtifactID string
+
+type ArtifactVersion string
 
 type MachineID string
 
@@ -23,12 +25,3 @@ const (
 	VolumeKindSystem VolumeKind = "system"
 	VolumeKindUser   VolumeKind = "user"
 )
-
-type Machine struct {
-	ID          MachineID    `json:"id"`
-	Phase       MachinePhase `json:"phase"`
-	RuntimeHost string       `json:"runtime_host,omitempty"`
-	Error       string       `json:"error,omitempty"`
-	CreatedAt   time.Time    `json:"created_at"`
-	StartedAt   *time.Time   `json:"started_at,omitempty"`
-}
diff --git a/internal/model/types.go b/internal/model/types.go
index 7aa29f5..3c83b15 100644
--- a/internal/model/types.go
+++ b/internal/model/types.go
@@ -6,22 +6,40 @@ import (
 	contracthost "github.com/getcompanion-ai/computer-host/contract"
 )
 
-type MachineRecord struct {
-	ID          contracthost.MachineID
-	Phase       contracthost.MachinePhase
-	RuntimeHost string
-	Error       string
-	CreatedAt   time.Time
-	StartedAt   *time.Time
-}
-
 type StoragePool string
 
-type VolumeRecord struct {
-	ID        contracthost.VolumeID
-	MachineID contracthost.MachineID
-	Kind      contracthost.VolumeKind
-	Pool      StoragePool
-	Path      string
-	CreatedAt time.Time
+const (
+	StoragePoolArtifacts    StoragePool = "artifacts"
+	StoragePoolMachineDisks StoragePool = "machine-disks"
+	StoragePoolState        StoragePool = "state"
+	StoragePoolUserVolumes  StoragePool = "user-volumes"
+)
+
+type ArtifactRecord struct {
+	Ref             contracthost.ArtifactRef
+	KernelImagePath string
+	RootFSPath      string
+	CreatedAt       time.Time
+}
+
+type MachineRecord struct {
+	ID             contracthost.MachineID
+	Artifact       contracthost.ArtifactRef
+	SystemVolumeID contracthost.VolumeID
+	UserVolumeIDs  []contracthost.VolumeID
+	Phase          contracthost.MachinePhase
+	RuntimeHost    string
+	Error          string
+	CreatedAt      time.Time
+	StartedAt      *time.Time
+}
+
+type VolumeRecord struct {
+	ID                contracthost.VolumeID
+	Kind              contracthost.VolumeKind
+	AttachedMachineID *contracthost.MachineID
+	SourceArtifact    *contracthost.ArtifactRef
+	Pool              StoragePool
+	Path              string
+	CreatedAt         time.Time
 }
diff --git a/internal/store/store.go b/internal/store/store.go
index 57db4b2..0604683 100644
--- a/internal/store/store.go
+++ b/internal/store/store.go
@@ -8,9 +8,17 @@ import (
 )
 
 type Store interface {
+	PutArtifact(context.Context, model.ArtifactRecord) error
+	GetArtifact(context.Context, contracthost.ArtifactRef) (*model.ArtifactRecord, error)
+	ListArtifacts(context.Context) ([]model.ArtifactRecord, error)
 	CreateMachine(context.Context, model.MachineRecord) error
 	GetMachine(context.Context, contracthost.MachineID) (*model.MachineRecord, error)
 	ListMachines(context.Context) ([]model.MachineRecord, error)
 	UpdateMachine(context.Context, model.MachineRecord) error
 	DeleteMachine(context.Context, contracthost.MachineID) error
+	CreateVolume(context.Context, model.VolumeRecord) error
+	GetVolume(context.Context, contracthost.VolumeID) (*model.VolumeRecord, error)
+	ListVolumes(context.Context) ([]model.VolumeRecord, error)
+	UpdateVolume(context.Context, model.VolumeRecord) error
+	DeleteVolume(context.Context, contracthost.VolumeID) error
 }