WIP: stable ordering for tool args

Right now we deserialize tool call definitions' arguments into golang
maps. These purposefully don't have a predictable iteration order,
whereas we want to maintain the order the user originally provided.

Unstable rendering of arguments means that we break the kv cache, which
this change fixes.

There's no way to build this in a fully backwards compatible way when
executing existing templates exactly as they are. We get around this by
rewriting templates dynamically just before they're rendered. This is
fragile, but perhaps the least bad option?

model/parsers/qwen3coder.go

@@ -268,17 +268,17 @@ func parseToolCall(raw qwenEventRawToolCall, tools []api.Tool) (api.ToolCall, er
 		}
 	}
 
-	toolCall.Function.Arguments = make(api.ToolCallFunctionArguments)
+	toolCall.Function.Arguments = api.NewToolCallFunctionArguments()
 	for _, parameter := range functionCall.Parameters {
 		// Look up the parameter type if we found the tool
 		var paramType api.PropertyType
-		if matchedTool != nil && matchedTool.Function.Parameters.Properties != nil {
-			if prop, ok := matchedTool.Function.Parameters.Properties[parameter.Name]; ok {
+		if matchedTool != nil && matchedTool.Function.Parameters.GetProperties() != nil {
+			if prop, ok := matchedTool.Function.Parameters.GetProperties().Get(parameter.Name); ok {
 				paramType = prop.Type
 			}
 		}
 
-		toolCall.Function.Arguments[parameter.Name] = parseValue(parameter.Value, paramType)
+		toolCall.Function.Arguments.Set(parameter.Name, parseValue(parameter.Value, paramType))
 	}
 
 	return toolCall, nil

model/parsers/qwen3coder_test.go

@@ -11,10 +11,25 @@ import (
 func tool(name string, props map[string]api.ToolProperty) api.Tool {
 	t := api.Tool{Type: "function", Function: api.ToolFunction{Name: name}}
 	t.Function.Parameters.Type = "object"
-	t.Function.Parameters.Properties = props
+	p := api.NewToolProperties()
+	for k, v := range props {
+		p.Set(k, v)
+	}
+	t.Function.Parameters.SetProperties(p)
 	return t
 }
 
+// Helper function to create ordered arguments for tests
+func makeArgs(pairs ...any) api.ToolCallFunctionArguments {
+	args := api.NewToolCallFunctionArguments()
+	for i := 0; i < len(pairs); i += 2 {
+		key := pairs[i].(string)
+		value := pairs[i+1]
+		args.Set(key, value)
+	}
+	return args
+}
+
 func TestQwenParserStreaming(t *testing.T) {
 	type step struct {
 		input      string
@@ -354,10 +369,7 @@ celsius
 			wantToolCall: api.ToolCall{
 				Function: api.ToolCallFunction{
 					Name: "get_current_temperature",
-					Arguments: map[string]any{
-						"location": "San Francisco",
-						"unit":     "celsius",
-					},
+					Arguments: makeArgs("location", "San Francisco", "unit", "celsius"),
 				},
 			},
 		},
@@ -375,10 +387,10 @@ celsius
 			wantToolCall: api.ToolCall{
 				Function: api.ToolCallFunction{
 					Name: "get current temperature",
-					Arguments: map[string]any{
-						"location with spaces": "San Francisco",
-						"unit with spaces":     "celsius",
-					},
+     Arguments: makeArgs(
+     	"location with spaces", "San Francisco",
+     	"unit with spaces", "celsius",
+     ),
 				},
 			},
 		},
@@ -400,10 +412,10 @@ San Francisco
 			wantToolCall: api.ToolCall{
 				Function: api.ToolCallFunction{
 					Name: "\"get current temperature\"",
-					Arguments: map[string]any{
-						"\"location with spaces\"": "San Francisco",
-						"\"unit with spaces\"":     "\"celsius\"",
-					},
+     Arguments: makeArgs(
+     	"\"location with spaces\"", "San Francisco",
+     	"\"unit with spaces\"", "\"celsius\"",
+     ),
 				},
 			},
 		},
@@ -434,12 +446,12 @@ true
 			wantToolCall: api.ToolCall{
 				Function: api.ToolCallFunction{
 					Name: "calculate",
-					Arguments: map[string]any{
-						"x":       3.14,
-						"y":       42,
-						"enabled": true,
-						"items":   []any{"a", "b", "c"},
-					},
+     Arguments: makeArgs(
+     	"x", 3.14,
+     	"y", 42,
+     	"enabled", true,
+     	"items", []any{"a", "b", "c"},
+     ),
 				},
 			},
 		},
@@ -455,9 +467,7 @@ ls && echo "done"
 			wantToolCall: api.ToolCall{
 				Function: api.ToolCallFunction{
 					Name: "exec",
-					Arguments: map[string]any{
-						"command": "ls && echo \"done\"",
-					},
+					Arguments: makeArgs("command", "ls && echo \"done\""),
 				},
 			},
 		},
@@ -472,9 +482,7 @@ ls && echo "a > b and a < b"
 			wantToolCall: api.ToolCall{
 				Function: api.ToolCallFunction{
 					Name: "exec",
-					Arguments: map[string]any{
-						"command": "ls && echo \"a > b and a < b\"",
-					},
+					Arguments: makeArgs("command", "ls && echo \"a > b and a < b\""),
 				},
 			},
 		},
@@ -492,10 +500,7 @@ Hello! 你好! 🌟 مرحبا
 			wantToolCall: api.ToolCall{
 				Function: api.ToolCallFunction{
 					Name: "获取天气",
-					Arguments: map[string]any{
-						"城市":      "北京",
-						"message": "Hello! 你好! 🌟 مرحبا",
-					},
+					Arguments: makeArgs("城市", "北京", "message", "Hello! 你好! 🌟 مرحبا"),
 				},
 			},
 		},