Feat issue 183 (#189)

* feat: add slash command support (e.g., /show model, /help)

* style: fix code formatting

* feat: implement robust context compression and error recovery with user notifications

pkg/agent/loop_test.go

@@ -2,6 +2,7 @@ package agent
 
 import (
 	"context"
+	"fmt"
 	"os"
 	"path/filepath"
 	"testing"
@@ -527,3 +528,99 @@ func TestToolResult_UserFacingToolDoesSendMessage(t *testing.T) {
 		t.Errorf("Expected 'Command output: hello world', got: %s", response)
 	}
 }
+
+// failFirstMockProvider fails on the first N calls with a specific error
+type failFirstMockProvider struct {
+	failures    int
+	currentCall int
+	failError   error
+	successResp string
+}
+
+func (m *failFirstMockProvider) Chat(ctx context.Context, messages []providers.Message, tools []providers.ToolDefinition, model string, opts map[string]interface{}) (*providers.LLMResponse, error) {
+	m.currentCall++
+	if m.currentCall <= m.failures {
+		return nil, m.failError
+	}
+	return &providers.LLMResponse{
+		Content:   m.successResp,
+		ToolCalls: []providers.ToolCall{},
+	}, nil
+}
+
+func (m *failFirstMockProvider) GetDefaultModel() string {
+	return "mock-fail-model"
+}
+
+// TestAgentLoop_ContextExhaustionRetry verify that the agent retries on context errors
+func TestAgentLoop_ContextExhaustionRetry(t *testing.T) {
+	tmpDir, err := os.MkdirTemp("", "agent-test-*")
+	if err != nil {
+		t.Fatalf("Failed to create temp dir: %v", err)
+	}
+	defer os.RemoveAll(tmpDir)
+
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				Workspace:         tmpDir,
+				Model:             "test-model",
+				MaxTokens:         4096,
+				MaxToolIterations: 10,
+			},
+		},
+	}
+
+	msgBus := bus.NewMessageBus()
+
+	// Create a provider that fails once with a context error
+	contextErr := fmt.Errorf("InvalidParameter: Total tokens of image and text exceed max message tokens")
+	provider := &failFirstMockProvider{
+		failures:    1,
+		failError:   contextErr,
+		successResp: "Recovered from context error",
+	}
+
+	al := NewAgentLoop(cfg, msgBus, provider)
+
+	// Inject some history to simulate a full context
+	sessionKey := "test-session-context"
+	// Create dummy history
+	history := []providers.Message{
+		{Role: "system", Content: "System prompt"},
+		{Role: "user", Content: "Old message 1"},
+		{Role: "assistant", Content: "Old response 1"},
+		{Role: "user", Content: "Old message 2"},
+		{Role: "assistant", Content: "Old response 2"},
+		{Role: "user", Content: "Trigger message"},
+	}
+	al.sessions.SetHistory(sessionKey, history)
+
+	// Call ProcessDirectWithChannel
+	// Note: ProcessDirectWithChannel calls processMessage which will execute runLLMIteration
+	response, err := al.ProcessDirectWithChannel(context.Background(), "Trigger message", sessionKey, "test", "test-chat")
+
+	if err != nil {
+		t.Fatalf("Expected success after retry, got error: %v", err)
+	}
+
+	if response != "Recovered from context error" {
+		t.Errorf("Expected 'Recovered from context error', got '%s'", response)
+	}
+
+	// We expect 2 calls: 1st failed, 2nd succeeded
+	if provider.currentCall != 2 {
+		t.Errorf("Expected 2 calls (1 fail + 1 success), got %d", provider.currentCall)
+	}
+
+	// Check final history length
+	finalHistory := al.sessions.GetHistory(sessionKey)
+	// We verify that the history has been modified (compressed)
+	// Original length: 6
+	// Expected behavior: compression drops ~50% of history (mid slice)
+	// We can assert that the length is NOT what it would be without compression.
+	// Without compression: 6 + 1 (new user msg) + 1 (assistant msg) = 8
+	if len(finalHistory) >= 8 {
+		t.Errorf("Expected history to be compressed (len < 8), got %d", len(finalHistory))
+	}
+}