From 90063cf5f0a0704d90c3ce0776d086ae0ffe780f Mon Sep 17 00:00:00 2001
From: tlongwell-block <109685178+tlongwell-block@users.noreply.github.com>
Date: Wed, 13 May 2026 09:40:41 -0400
Subject: [PATCH] fix: skip empty assistant turns instead of placeholder space
 (#560)

---
 crates/sprout-agent/src/llm.rs | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/crates/sprout-agent/src/llm.rs b/crates/sprout-agent/src/llm.rs
index 5aa912756..82b0c803f 100644
--- a/crates/sprout-agent/src/llm.rs
+++ b/crates/sprout-agent/src/llm.rs
@@ -127,9 +127,11 @@ fn anthropic_body(cfg: &Config, history: &[HistoryItem], tools: &[ToolDef]) -> V
                         "name": c.name, "input": c.arguments }));
                 }
                 if content.is_empty() {
-                    // Anthropic requires non-empty content arrays AND rejects
-                    // empty text blocks. A single space satisfies both.
-                    content.push(json!({ "type": "text", "text": " " }));
+                    // Empty assistant turn (no text, no tool calls) — skip it.
+                    // Anthropic rejects empty text blocks, and a placeholder
+                    // just defers the problem. No tool_use = no pairing
+                    // constraint, so omitting is safe.
+                    continue;
                 }
                 messages.push(json!({ "role": "assistant", "content": content }));
             }