diff --git a/cmd/generate_changelog/incoming/1828.txt b/cmd/generate_changelog/incoming/1828.txt
new file mode 100644
index 00000000..9ad30b0d
--- /dev/null
+++ b/cmd/generate_changelog/incoming/1828.txt
@@ -0,0 +1,6 @@
+### PR [#1828](https://github.com/danielmiessler/Fabric/pull/1828) by [ksylvan](https://github.com/ksylvan): Fix empty string detection in chatter and AI clients
+
+- Chore: improve message handling by trimming whitespace in content checks
+- Remove default space in `BuildSession` message content
+- Trim whitespace in `anthropic` message content check
+- Trim whitespace in `gemini` message content check
diff --git a/internal/core/chatter.go b/internal/core/chatter.go
index 02ba28a0..a1a60371 100644
--- a/internal/core/chatter.go
+++ b/internal/core/chatter.go
@@ -175,7 +175,7 @@ func (o *Chatter) BuildSession(request *domain.ChatRequest, raw bool) (session *
 	if request.Message == nil {
 		request.Message = &chat.ChatCompletionMessage{
 			Role:    chat.ChatMessageRoleUser,
-			Content: " ",
+			Content: "",
 		}
 	}
 
diff --git a/internal/plugins/ai/anthropic/anthropic.go b/internal/plugins/ai/anthropic/anthropic.go
index 5ddb3048..67cb2066 100644
--- a/internal/plugins/ai/anthropic/anthropic.go
+++ b/internal/plugins/ai/anthropic/anthropic.go
@@ -356,7 +356,7 @@ func (an *Client) toMessages(msgs []*chat.ChatCompletionMessage) (ret []anthropi
 	lastRoleWasUser := false
 
 	for _, msg := range msgs {
-		if msg.Content == "" {
+		if strings.TrimSpace(msg.Content) == "" {
 			continue // Skip empty messages
 		}
 
diff --git a/internal/plugins/ai/gemini/gemini.go b/internal/plugins/ai/gemini/gemini.go
index af68ba0a..251d92a7 100644
--- a/internal/plugins/ai/gemini/gemini.go
+++ b/internal/plugins/ai/gemini/gemini.go
@@ -456,7 +456,7 @@ func (o *Client) convertMessages(msgs []*chat.ChatCompletionMessage) []*genai.Co
 			content.Role = "user"
 		}
 
-		if msg.Content != "" {
+		if strings.TrimSpace(msg.Content) != "" {
 			content.Parts = append(content.Parts, &genai.Part{Text: msg.Content})
 		}