diff --git a/agent/agentcontainers/api.go b/agent/agentcontainers/api.go
index 3e42a73746..a6c2167ca8 100644
--- a/agent/agentcontainers/api.go
+++ b/agent/agentcontainers/api.go
@@ -1063,6 +1063,10 @@ func (api *API) maybeInjectSubAgentIntoContainerLocked(ctx context.Context, dc c
 		)
 		return nil
 	}
+	if proc.agent.ID == uuid.Nil {
+		proc.agent.Architecture = arch
+	}
+
 	agentBinaryPath, err := os.Executable()
 	if err != nil {
 		return xerrors.Errorf("get agent binary path: %w", err)
@@ -1107,6 +1111,8 @@ func (api *API) maybeInjectSubAgentIntoContainerLocked(ctx context.Context, dc c
 
 	subAgentConfig := proc.agent.CloneConfig(dc)
 	if proc.agent.ID == uuid.Nil || maybeRecreateSubAgent {
+		subAgentConfig.Architecture = arch
+
 		// Detect workspace folder by executing `pwd` in the container.
 		// NOTE(mafredri): This is a quick and dirty way to detect the
 		// workspace folder inside the container. In the future we will
diff --git a/agent/agentcontainers/api_test.go b/agent/agentcontainers/api_test.go
index 526c7432c3..3bf6206e2a 100644
--- a/agent/agentcontainers/api_test.go
+++ b/agent/agentcontainers/api_test.go
@@ -252,6 +252,15 @@ func (m *fakeSubAgentClient) Create(ctx context.Context, agent agentcontainers.S
 			}
 		}
 	}
+	if agent.Name == "" {
+		return agentcontainers.SubAgent{}, xerrors.New("name must be set")
+	}
+	if agent.Architecture == "" {
+		return agentcontainers.SubAgent{}, xerrors.New("architecture must be set")
+	}
+	if agent.OperatingSystem == "" {
+		return agentcontainers.SubAgent{}, xerrors.New("operating system must be set")
+	}
 	agent.ID = uuid.New()
 	agent.AuthToken = uuid.New()
 	if m.agents == nil {