diff --git a/agent.go b/agent.go
index 54a83a56394f1e92cd2803dcf1cad87567829aaa..7fcf9cb2a9203d279c18c016b71df972abc287e1 100644
--- a/agent.go
+++ b/agent.go
@@ -868,7 +868,7 @@ func (a *agent) prepareTools(tools []AgentTool, activeTools []string, disableAll
 	return preparedTools
 }
 
-// validateAndRepairToolCall validates a tool call and attempts repair if validation fails
+// validateAndRepairToolCall validates a tool call and attempts repair if validation fails.
 func (a *agent) validateAndRepairToolCall(ctx context.Context, toolCall ToolCallContent, availableTools []AgentTool, systemPrompt string, messages []Message, repairFunc RepairToolCallFunction) ToolCallContent {
 	if err := a.validateToolCall(toolCall, availableTools); err == nil {
 		return toolCall
@@ -896,7 +896,7 @@ func (a *agent) validateAndRepairToolCall(ctx context.Context, toolCall ToolCall
 	}
 }
 
-// validateToolCall validates a tool call against available tools and their schemas
+// validateToolCall validates a tool call against available tools and their schemas.
 func (a *agent) validateToolCall(toolCall ToolCallContent, availableTools []AgentTool) error {
 	var tool AgentTool
 	for _, t := range availableTools {
@@ -1009,7 +1009,7 @@ func WithRepairToolCall(fn RepairToolCallFunction) AgentOption {
 	}
 }
 
-// processStepStream processes a single step's stream and returns the step result
+// processStepStream processes a single step's stream and returns the step result.
 func (a *agent) processStepStream(ctx context.Context, stream StreamResponse, opts AgentStreamCall, _ []StepResult) (StepResult, bool, error) {
 	var stepContent []Content
 	var stepToolCalls []ToolCallContent
diff --git a/content.go b/content.go
index f2f9aa93dbb6c583efd2b113232966c0035c992b..375f216972b1b46c951c54d6b3fa1e9454b07829 100644
--- a/content.go
+++ b/content.go
@@ -45,7 +45,7 @@ type ProviderOptions map[string]map[string]any
 // - `tool-calls`: model triggered tool calls
 // - `error`: model stopped because of an error
 // - `other`: model stopped for other reasons
-// - `unknown`: the model has not transmitted a finish reason
+// - `unknown`: the model has not transmitted a finish reason.
 type FinishReason string
 
 const (
@@ -450,7 +450,7 @@ func (p ProviderDefinedTool) GetName() string {
 	return p.Name
 }
 
-// Helpers
+// Helpers.
 func NewUserMessage(prompt string, files ...FilePart) Message {
 	content := []MessagePart{
 		TextPart{
diff --git a/providers/anthropic.go b/providers/anthropic.go
index b0ed3f36c2b3a808b68e14244222b0d0336a4068..61ea657896a549343d4c038166b3babee6400e2b 100644
--- a/providers/anthropic.go
+++ b/providers/anthropic.go
@@ -382,7 +382,7 @@ func toAnthropicTools(tools []ai.Tool, toolChoice *ai.ToolChoice, disableParalle
 				},
 			}
 		}
-		return
+		return anthropicTools, anthropicToolChoice, warnings
 	}
 
 	switch *toolChoice {
@@ -401,7 +401,7 @@ func toAnthropicTools(tools []ai.Tool, toolChoice *ai.ToolChoice, disableParalle
 			},
 		}
 	case ai.ToolChoiceNone:
-		return
+		return anthropicTools, anthropicToolChoice, warnings
 	default:
 		anthropicToolChoice = &anthropic.ToolChoiceUnionParam{
 			OfTool: &anthropic.ToolChoiceToolParam{
@@ -411,7 +411,7 @@ func toAnthropicTools(tools []ai.Tool, toolChoice *ai.ToolChoice, disableParalle
 			},
 		}
 	}
-	return
+	return anthropicTools, anthropicToolChoice, warnings
 }
 
 func toAnthropicPrompt(prompt ai.Prompt, sendReasoningData bool) ([]anthropic.TextBlockParam, []anthropic.MessageParam, []ai.CallWarning) {
diff --git a/providers/openai.go b/providers/openai.go
index 4615a359b18b96d081950e31e8b3a399b921c5d6..3e1832c4944b4109373d1874336c6f6a4c48e9c3 100644
--- a/providers/openai.go
+++ b/providers/openai.go
@@ -839,7 +839,7 @@ func toOpenAiTools(tools []ai.Tool, toolChoice *ai.ToolChoice) (openAiTools []op
 		})
 	}
 	if toolChoice == nil {
-		return
+		return openAiTools, openAiToolChoice, warnings
 	}
 
 	switch *toolChoice {
@@ -861,7 +861,7 @@ func toOpenAiTools(tools []ai.Tool, toolChoice *ai.ToolChoice) (openAiTools []op
 			},
 		}
 	}
-	return
+	return openAiTools, openAiToolChoice, warnings
 }
 
 func toOpenAiPrompt(prompt ai.Prompt) ([]openai.ChatCompletionMessageParamUnion, []ai.CallWarning) {
@@ -1129,7 +1129,7 @@ func toOpenAiPrompt(prompt ai.Prompt) ([]openai.ChatCompletionMessageParamUnion,
 	return messages, warnings
 }
 
-// parseAnnotationsFromDelta parses annotations from the raw JSON of a delta
+// parseAnnotationsFromDelta parses annotations from the raw JSON of a delta.
 func parseAnnotationsFromDelta(delta openai.ChatCompletionChunkChoiceDelta) []openai.ChatCompletionMessageAnnotation {
 	var annotations []openai.ChatCompletionMessageAnnotation