diff --git a/pkg/providers/openai_compat/provider.go b/pkg/providers/openai_compat/provider.go
index 996a451ed..a614d52c2 100644
--- a/pkg/providers/openai_compat/provider.go
+++ b/pkg/providers/openai_compat/provider.go
@@ -545,13 +545,23 @@ func (p *Provider) finalizeTools(tools []ToolDefinition, options map[string]any)
 		return tools
 	}
 
-	// 3. Sanitization / Explicit Force Path
-	// Build compatible map based on 'useStrict' decision
+	// 3. Sanitization / Explicit Force Path / Edge Case Handling
+	// Decide whether to use strict mode
 	useStrict := isNative
 	if hasForce {
-		useStrict = forceStrict
+		if forceStrict && !isNative {
+			// Non-native providers don't support strict mode, ignore user setting
+			log.Printf(
+				"openai_compat: strict_mode=true ignored for non-OpenAI provider %q (unsupported field)",
+				p.apiBase,
+			)
+			useStrict = false
+		} else {
+			useStrict = forceStrict
+		}
 	}
 
+	// Build compatible map based on 'useStrict' decision
 	out := make([]any, 0, len(tools))
 	for _, t := range tools {
 		toolMap := map[string]any{
diff --git a/pkg/providers/openai_compat/provider_test.go b/pkg/providers/openai_compat/provider_test.go
index 41f278a1b..74000aeb7 100644
--- a/pkg/providers/openai_compat/provider_test.go
+++ b/pkg/providers/openai_compat/provider_test.go
@@ -841,3 +841,97 @@ func TestSerializeMessages_StripsSystemParts(t *testing.T) {
 		t.Fatal("system_parts should not appear in serialized output")
 	}
 }
+
+func TestFinalizeTools_StrictMode(t *testing.T) {
+	tools := []ToolDefinition{
+		{
+			Type: "function",
+			Function: ToolFunctionDefinition{
+				Name:        "test_func",
+				Description: "testing",
+				Parameters:  map[string]any{"type": "object"},
+			},
+		},
+	}
+
+	tests := []struct {
+		name       string
+		apiBase    string
+		options    map[string]any
+		wantStrict bool
+		wantSame   bool // whether it should be a direct pass-through
+	}{
+		{
+			name:       "native openai - default",
+			apiBase:    "https://api.openai.com/v1",
+			options:    nil,
+			wantStrict: false,
+			wantSame:   true,
+		},
+		{
+			name:       "native openai - force strict",
+			apiBase:    "https://api.openai.com/v1",
+			options:    map[string]any{"strict_mode": true},
+			wantStrict: true,
+			wantSame:   false,
+		},
+		{
+			name:       "native openai - force off",
+			apiBase:    "https://api.openai.com/v1",
+			options:    map[string]any{"strict_mode": false},
+			wantStrict: false,
+			wantSame:   false,
+		},
+		{
+			name:       "non-native - default (stripped)",
+			apiBase:    "https://api.deepseek.com/v1",
+			options:    nil,
+			wantStrict: false,
+			wantSame:   false,
+		},
+		{
+			name:       "non-native - force strict (ignored)",
+			apiBase:    "https://api.groq.com/openai/v1",
+			options:    map[string]any{"strict_mode": true},
+			wantStrict: false,
+			wantSame:   false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p := &Provider{apiBase: tt.apiBase}
+			res := p.finalizeTools(tools, tt.options)
+
+			if tt.wantSame {
+				if fmt.Sprintf("%p", res) != fmt.Sprintf("%p", tools) {
+					t.Errorf("expected pass-through, got new slice")
+				}
+				return
+			}
+
+			// Verify if it's a slice of maps with/without strict
+			resSlice, ok := res.([]any)
+			if !ok {
+				t.Fatalf("expected []any, got %T", res)
+			}
+			if len(resSlice) != 1 {
+				t.Fatalf("expected 1 tool, got %d", len(resSlice))
+			}
+
+			toolMap := resSlice[0].(map[string]any)
+			fnMap := toolMap["function"].(map[string]any)
+			val, hasStrict := fnMap["strict"]
+
+			if tt.wantStrict {
+				if !hasStrict || val != true {
+					t.Errorf("expected strict: true, got %v", val)
+				}
+			} else {
+				if hasStrict {
+					t.Errorf("did not expect strict field, got %v", val)
+				}
+			}
+		})
+	}
+}