diff --git a/agents/registry_build_test.go b/agents/registry_build_test.go
new file mode 100644
index 0000000..5a3c9a5
--- /dev/null
+++ b/agents/registry_build_test.go
@@ -0,0 +1,173 @@
+package agents
+
+import (
+	"log/slog"
+	"os"
+	"testing"
+
+	"github.com/enmanuel/agents/internal/config"
+	toolmemory "github.com/enmanuel/agents/tools/memorytools"
+)
+
+func TestBuildToolRegistry_MinimalConfig(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelError}))
+	cfg := &config.AgentConfig{
+		Agent: config.AgentMeta{ID: "test-agent"},
+	}
+	roomCtx := &toolmemory.RoomContext{}
+
+	reg := buildToolRegistry(cfg, nil, nil, nil, nil, nil, nil, nil, nil, roomCtx, logger)
+
+	// Always-registered tools: current_time, weather, matrix_send
+	names := reg.Names()
+	if len(names) < 3 {
+		t.Fatalf("expected at least 3 always-on tools, got %d: %v", len(names), names)
+	}
+	assertToolRegistered(t, reg, "current_time")
+	assertToolRegistered(t, reg, "get_weather")
+	assertToolRegistered(t, reg, "matrix_send")
+}
+
+func TestBuildToolRegistry_HTTPEnabled(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelError}))
+	cfg := &config.AgentConfig{
+		Agent: config.AgentMeta{ID: "test-agent"},
+		Tools: config.ToolsCfg{
+			HTTP: config.HTTPToolCfg{Enabled: true, AllowedDomains: []string{"example.com"}},
+		},
+	}
+	roomCtx := &toolmemory.RoomContext{}
+
+	reg := buildToolRegistry(cfg, nil, nil, nil, nil, nil, nil, nil, nil, roomCtx, logger)
+
+	assertToolRegistered(t, reg, "http_get")
+	assertToolRegistered(t, reg, "http_post")
+}
+
+func TestBuildToolRegistry_HTTPDisabled(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelError}))
+	cfg := &config.AgentConfig{
+		Agent: config.AgentMeta{ID: "test-agent"},
+	}
+	roomCtx := &toolmemory.RoomContext{}
+
+	reg := buildToolRegistry(cfg, nil, nil, nil, nil, nil, nil, nil, nil, roomCtx, logger)
+
+	assertToolNotRegistered(t, reg, "http_get")
+	assertToolNotRegistered(t, reg, "http_post")
+}
+
+func TestBuildToolRegistry_FileOpsReadOnly(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelError}))
+	cfg := &config.AgentConfig{
+		Agent: config.AgentMeta{ID: "test-agent"},
+		Tools: config.ToolsCfg{
+			FileOps: config.FileOpsCfg{Enabled: true, ReadOnly: true, AllowedPaths: []string{"/tmp"}},
+		},
+	}
+	roomCtx := &toolmemory.RoomContext{}
+
+	reg := buildToolRegistry(cfg, nil, nil, nil, nil, nil, nil, nil, nil, roomCtx, logger)
+
+	assertToolRegistered(t, reg, "read_file")
+	assertToolRegistered(t, reg, "list_directory")
+	assertToolNotRegistered(t, reg, "write_file")
+	assertToolNotRegistered(t, reg, "append_file")
+	assertToolNotRegistered(t, reg, "delete_file")
+}
+
+func TestBuildToolRegistry_FileOpsReadWrite(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelError}))
+	cfg := &config.AgentConfig{
+		Agent: config.AgentMeta{ID: "test-agent"},
+		Tools: config.ToolsCfg{
+			FileOps: config.FileOpsCfg{Enabled: true, ReadOnly: false, AllowedPaths: []string{"/tmp"}},
+		},
+	}
+	roomCtx := &toolmemory.RoomContext{}
+
+	reg := buildToolRegistry(cfg, nil, nil, nil, nil, nil, nil, nil, nil, roomCtx, logger)
+
+	assertToolRegistered(t, reg, "read_file")
+	assertToolRegistered(t, reg, "list_directory")
+	assertToolRegistered(t, reg, "write_file")
+	assertToolRegistered(t, reg, "append_file")
+	assertToolRegistered(t, reg, "delete_file")
+}
+
+func TestBuildToolRegistry_IMDbEnabled(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelError}))
+	cfg := &config.AgentConfig{
+		Agent: config.AgentMeta{ID: "test-agent"},
+		Tools: config.ToolsCfg{
+			IMDb: config.IMDbToolCfg{Enabled: true},
+		},
+	}
+	roomCtx := &toolmemory.RoomContext{}
+
+	reg := buildToolRegistry(cfg, nil, nil, nil, nil, nil, nil, nil, nil, roomCtx, logger)
+
+	assertToolRegistered(t, reg, "imdb_search")
+}
+
+func TestBuildToolRegistry_SSHEnabled(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelError}))
+	cfg := &config.AgentConfig{
+		Agent: config.AgentMeta{ID: "test-agent"},
+		Tools: config.ToolsCfg{
+			SSH: config.SSHToolCfg{Enabled: true},
+		},
+	}
+	roomCtx := &toolmemory.RoomContext{}
+
+	// SSH tool requires an executor; passing nil is fine for registration (only used at exec time)
+	reg := buildToolRegistry(cfg, nil, nil, nil, nil, nil, nil, nil, nil, roomCtx, logger)
+
+	assertToolRegistered(t, reg, "ssh_command")
+}
+
+func TestBuildToolRegistry_ToolCount(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelError}))
+
+	// Enable everything that doesn't need external deps
+	cfg := &config.AgentConfig{
+		Agent: config.AgentMeta{ID: "test-agent"},
+		Tools: config.ToolsCfg{
+			HTTP:    config.HTTPToolCfg{Enabled: true},
+			SSH:     config.SSHToolCfg{Enabled: true},
+			FileOps: config.FileOpsCfg{Enabled: true, AllowedPaths: []string{"/tmp"}},
+			IMDb:    config.IMDbToolCfg{Enabled: true},
+		},
+	}
+	roomCtx := &toolmemory.RoomContext{}
+
+	reg := buildToolRegistry(cfg, nil, nil, nil, nil, nil, nil, nil, nil, roomCtx, logger)
+
+	// 3 always-on + 2 HTTP + 1 SSH + 5 file + 1 IMDb = 12
+	expected := 12
+	if got := reg.Len(); got != expected {
+		t.Errorf("expected %d tools, got %d: %v", expected, got, reg.Names())
+	}
+}
+
+// ── Test helpers ────────────────────────────────────────────────────────────
+
+func assertToolRegistered(t *testing.T, reg interface{ Names() []string }, name string) {
+	t.Helper()
+	for _, n := range reg.Names() {
+		if n == name {
+			return
+		}
+	}
+	t.Errorf("expected tool %q to be registered, but it was not. Registered: %v", name, reg.Names())
+}
+
+func assertToolNotRegistered(t *testing.T, reg interface{ Names() []string }, name string) {
+	t.Helper()
+	for _, n := range reg.Names() {
+		if n == name {
+			t.Errorf("expected tool %q NOT to be registered, but it was", name)
+			return
+		}
+	}
+}