Expose version/build metadata and improve provider error messaging

internal/openai/types.go

@@ -1,5 +1,10 @@
 package openai
 
+import (
+	"fmt"
+	"strings"
+)
+
 // ChatMessage represents a single message within a chat completion request or response.
 type ChatMessage struct {
 	Role    string `json:"role"`
@@ -50,6 +55,48 @@ type ChatCompletionStreamEvent struct {
 // ChatCompletionStreamHandler consumes streaming completion events.
 type ChatCompletionStreamHandler func(ChatCompletionStreamEvent) error
 
+// RequestError captures an error response returned by the API together with the HTTP status code.
+type RequestError struct {
+	Status   int
+	Response ErrorResponse
+}
+
+// Error implements the error interface.
+func (e *RequestError) Error() string {
+	if e == nil {
+		return ""
+	}
+	msg := strings.TrimSpace(e.Response.Error.Message)
+	if msg == "" {
+		return fmt.Sprintf("api error (status %d)", e.Status)
+	}
+	return fmt.Sprintf("api error (status %d): %s", e.Status, msg)
+}
+
+// StatusCode returns the originating HTTP status code.
+func (e *RequestError) StatusCode() int {
+	if e == nil {
+		return 0
+	}
+	return e.Status
+}
+
+// Message returns the raw message provided by the API, if any.
+func (e *RequestError) Message() string {
+	if e == nil {
+		return ""
+	}
+	return e.Response.Error.Message
+}
+
+// Type returns the OpenAI error type string, when present.
+func (e *RequestError) Type() string {
+	if e == nil {
+		return ""
+	}
+	return e.Response.Error.Type
+}
+
 // APIError captures structured error responses returned by the API.
 type APIError struct {
 	Message string `json:"message"`