feat: Add MaxTokens option for AI model output control

Author: 2b3pro

cmd/generate_changelog/incoming/1747.txt

@@ -0,0 +1,7 @@
+### PR [#1747](https://github.com/danielmiessler/Fabric/pull/1747) by [2b3pro](https://github.com/2b3pro): feat: Add MaxTokens option for AI model output control
+
+- Add MaxTokens configuration option allowing users to specify the maximum number of tokens to generate in AI model responses
+- Integrate MaxTokens support across multiple AI providers including Anthropic, Gemini, and Ollama with updated CLI flags and example configuration
+- Enhance ParseFileChanges function to support both JSON format and markdown format for better compatibility with different AI model outputs
+- Support max_completion_tokens for GPT-5 models with conditional logic to map MaxTokens to the appropriate parameter for OpenAI API requests
+- Add test case to validate proper parameter mapping for GPT-5 models according to their specific API requirements

internal/cli/example.yaml

@@ -17,6 +17,9 @@ topp: 0.67
 temperature: 0.88
 seed: 42
 
+# Maximum number of tokens to generate
+maxTokens: 1000
+
 stream: true
 raw: false
 

internal/cli/flags.go

@@ -103,6 +103,7 @@ type Flags struct {
 	Notification                    bool                 `long:"notification" yaml:"notification" description:"Send desktop notification when command completes"`
 	NotificationCommand             string               `long:"notification-command" yaml:"notificationCommand" description:"Custom command to run for notifications (overrides built-in notifications)"`
 	Thinking                        domain.ThinkingLevel `long:"thinking" yaml:"thinking" description:"Set reasoning/thinking level (e.g., off, low, medium, high, or numeric tokens for Anthropic or Google Gemini)"`
+	MaxTokens                       int                  `long:"max-tokens" yaml:"maxTokens" description:"Maximum number of tokens to generate (provider-specific limits apply)"`
 	Debug                           int                  `long:"debug" description:"Set debug level (0=off, 1=basic, 2=detailed, 3=trace)" default:"0"`
 }
 
@@ -464,6 +465,7 @@ func (o *Flags) BuildChatOptions() (ret *domain.ChatOptions, err error) {
 		Raw:                 o.Raw,
 		Seed:                o.Seed,
 		Thinking:            o.Thinking,
+		MaxTokens:           o.MaxTokens,
 		ModelContextLength:  o.ModelContextLength,
 		Search:              o.Search,
 		SearchLocation:      o.SearchLocation,

internal/cli/help.go

@@ -91,6 +91,7 @@ var flagDescriptionMap = map[string]string{
 	"notification":               "send_desktop_notification",
 	"notification-command":       "custom_notification_command",
 	"thinking":                   "set_reasoning_thinking_level",
+	"max-tokens":                 "maximum_tokens_to_generate",
 	"debug":                      "set_debug_level",
 }