diff --git a/go.mod b/go.mod
new file mode 100644
index 00000000..49c4407e
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module chat-agent-system
+
+go 1.27.1
diff --git a/internal/config/config.go b/internal/config/config.go
new file mode 100644
index 00000000..fd9447fa
--- /dev/null
+++ b/internal/config/config.go
@@ -0,0 +1,114 @@
+package config
+
+import (
+	"bufio"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+type Config struct {
+	Env              string        `json:"env"`
+	DataDir          string        `json:"data_dir"`
+	AgentBackend     string        `json:"agent_backend"`
+	AgentTimeout     time.Duration `json:"agent_timeout"`
+	CursorAPIKey     string        `json:"cursor_api_key"`
+	CursorModel      string        `json:"cursor_model"`
+	CursorBin        string        `json:"cursor_bin"`
+	CursorBridgeBin  string        `json:"cursor_bridge_bin"`
+	PiAgentBin       string        `json:"pi_agent_bin"`
+	PiAgentBridgeBin string        `json:"pi_agent_bridge_bin"`
+	PiAgentProvider  string        `json:"pi_agent_provider"`
+	PiAgentModel     string        `json:"pi_agent_model"`
+	KbDbHost         string        `json:"kb_db_host"`
+	KbDbPort         int           `json:"kb_db_port"`
+	KbDbUser         string        `json:"kb_db_user"`
+	KbDbPassword     string        `json:"kb_db_password"`
+	KbDbName         string        `json:"kb_db_name"`
+}
+
+func Load(path string) (*Config, error) {
+	cfg := &Config{
+		Env:              "dev",
+		DataDir:          "./data/dev",
+		AgentBackend:     "pi-agent",
+		AgentTimeout:     30 * time.Minute,
+		CursorModel:      "auto",
+		CursorBin:        "/usr/local/bin/cursor",
+		CursorBridgeBin:  "tools/cursor-bridge/index.mjs",
+		PiAgentBin:       "/opt/homebrew/bin/pi",
+		PiAgentBridgeBin: "tools/pi-bridge/index.mjs",
+		PiAgentProvider:  "anthropic",
+		PiAgentModel:     "claude-3-7-sonnet",
+		KbDbHost:         "127.0.0.1",
+		KbDbPort:         55432,
+		KbDbUser:         "regkb",
+		KbDbPassword:     "shared_kb_secret_pass",
+		KbDbName:         "regulations",
+	}
+
+	f, err := os.Open(path)
+	if err == nil {
+		defer f.Close()
+		scanner := bufio.NewScanner(f)
+		for scanner.Scan() {
+			line := strings.TrimSpace(scanner.Text())
+			if line == "" || strings.HasPrefix(line, "#") {
+				continue
+			}
+			parts := strings.SplitN(line, "=", 2)
+			if len(parts) != 2 {
+				continue
+			}
+			key := strings.TrimSpace(parts[0])
+			val := strings.TrimSpace(parts[1])
+			if commentIdx := strings.Index(val, " #"); commentIdx != -1 {
+				val = strings.TrimSpace(val[:commentIdx])
+			}
+
+			switch key {
+			case "ENV":
+				cfg.Env = val
+			case "DATA_DIR":
+				cfg.DataDir = val
+			case "AGENT_BACKEND":
+				cfg.AgentBackend = val
+			case "AGENT_TIMEOUT":
+				if d, err := time.ParseDuration(val); err == nil {
+					cfg.AgentTimeout = d
+				}
+			case "CURSOR_API_KEY":
+				cfg.CursorAPIKey = val
+			case "CURSOR_MODEL":
+				cfg.CursorModel = val
+			case "CURSOR_BIN":
+				cfg.CursorBin = val
+			case "CURSOR_BRIDGE_BIN":
+				cfg.CursorBridgeBin = val
+			case "PI_AGENT_BIN":
+				cfg.PiAgentBin = val
+			case "PI_AGENT_BRIDGE_BIN":
+				cfg.PiAgentBridgeBin = val
+			case "PI_AGENT_PROVIDER":
+				cfg.PiAgentProvider = val
+			case "PI_AGENT_MODEL":
+				cfg.PiAgentModel = val
+			case "KB_DB_HOST":
+				cfg.KbDbHost = val
+			case "KB_DB_PORT":
+				if p, err := strconv.Atoi(val); err == nil {
+					cfg.KbDbPort = p
+				}
+			case "KB_DB_USER":
+				cfg.KbDbUser = val
+			case "KB_DB_PASSWORD":
+				cfg.KbDbPassword = val
+			case "KB_DB_NAME":
+				cfg.KbDbName = val
+			}
+		}
+	}
+
+	return cfg, nil
+}
diff --git a/internal/config/config_test.go b/internal/config/config_test.go
new file mode 100644
index 00000000..bf369f19
--- /dev/null
+++ b/internal/config/config_test.go
@@ -0,0 +1,45 @@
+package config_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"chat-agent-system/internal/config"
+)
+
+func TestConfigLoadDefaultsAndFile(t *testing.T) {
+	tmpDir := t.TempDir()
+	envPath := filepath.Join(tmpDir, ".env")
+	envContent := `ENV=dev
+DATA_DIR=./data/test_data
+AGENT_BACKEND=pi-agent
+AGENT_TIMEOUT=15m
+KB_DB_PORT=55432
+`
+	if err := os.WriteFile(envPath, []byte(envContent), 0o644); err != nil {
+		t.Fatalf("failed to write test env: %v", err)
+	}
+
+	cfg, err := config.Load(envPath)
+	if err != nil {
+		t.Fatalf("unexpected error loading config: %v", err)
+	}
+
+	if cfg.Env != "dev" {
+		t.Errorf("expected Env 'dev', got %q", cfg.Env)
+	}
+	if cfg.DataDir != "./data/test_data" {
+		t.Errorf("expected DataDir './data/test_data', got %q", cfg.DataDir)
+	}
+	if cfg.AgentBackend != "pi-agent" {
+		t.Errorf("expected AgentBackend 'pi-agent', got %q", cfg.AgentBackend)
+	}
+	if cfg.AgentTimeout != 15*time.Minute {
+		t.Errorf("expected AgentTimeout 15m, got %v", cfg.AgentTimeout)
+	}
+	if cfg.KbDbPort != 55432 {
+		t.Errorf("expected KbDbPort 55432, got %d", cfg.KbDbPort)
+	}
+}