diff --git a/crates/g3-core/src/fixed_filter_json.rs b/crates/g3-core/src/fixed_filter_json.rs
index 69dbf81..b86db42 100644
--- a/crates/g3-core/src/fixed_filter_json.rs
+++ b/crates/g3-core/src/fixed_filter_json.rs
@@ -106,6 +106,40 @@ pub fn fixed_filter_json_tool_calls(content: &str) -> String {
                     _ => {}
                 }
             }
+            
+            // CRITICAL FIX: After counting braces, if still in suppression mode,
+            // check if a new tool call pattern appears. This handles truncated JSON
+            // followed by complete JSON.
+            if state.suppression_mode {
+                let current_json_start = state.json_start_in_buffer.unwrap();
+                // Don't require newline - the new JSON might be concatenated directly
+                let tool_call_regex = Regex::new(r#"\{\s*"tool"\s*:\s*""#).unwrap();
+                
+                // Look for new tool call patterns after the current one
+                if let Some(captures) = tool_call_regex.find(&state.buffer[current_json_start + 1..]) {
+                    let new_json_start = current_json_start + 1 + captures.start() + captures.as_str().find('{').unwrap();
+                    
+                    debug!("Detected new tool call at position {} while processing incomplete one at {} - discarding old", new_json_start, current_json_start);
+                    
+                    // The previous JSON was incomplete/malformed
+                    // Return content before the old JSON (if any)
+                    let content_before_old_json = if current_json_start > state.content_returned_up_to {
+                        state.buffer[state.content_returned_up_to..current_json_start].to_string()
+                    } else {
+                        String::new()
+                    };
+                    
+                    // Update state to skip the incomplete JSON and position at the new one
+                    // We'll process the new JSON on the next call
+                    state.content_returned_up_to = new_json_start;
+                    state.suppression_mode = false;
+                    state.json_start_in_buffer = None;
+                    state.brace_depth = 0;
+                    
+                    return content_before_old_json;
+                }
+            }
+            
             // Still in suppression mode, return empty string (content is being accumulated)
             return String::new();
         }
diff --git a/crates/g3-core/src/fixed_filter_tests.rs b/crates/g3-core/src/fixed_filter_tests.rs
index f8997c8..39ae617 100644
--- a/crates/g3-core/src/fixed_filter_tests.rs
+++ b/crates/g3-core/src/fixed_filter_tests.rs
@@ -347,4 +347,38 @@ More text"#;
         let expected = "Some text before\n\nText after";
         assert_eq!(final_result, expected);
     }
+
+    /// Test handling of truncated JSON followed by complete JSON (the json_err pattern)
+    #[test]
+    fn test_truncated_then_complete_json() {
+        reset_fixed_json_tool_state();
+
+        // Simulate the pattern from json_err trace:
+        // 1. Incomplete/truncated JSON appears
+        // 2. Then the same complete JSON appears
+        let chunks = vec![
+            "Some text\n",
+            r#"{"tool": "str_replace", "args": {"diff":"...","file_path":"./crates/g3-cli"#,  // Truncated
+            r#"{"tool": "str_replace", "args": {"diff":"...","file_path":"./crates/g3-cli/src/lib.rs"}}"#,  // Complete
+            "\nMore text",
+        ];
+
+        let mut results = Vec::new();
+        for (i, chunk) in chunks.iter().enumerate() {
+            let result = fixed_filter_json_tool_calls(chunk);
+            println!("Chunk {}: {:?} -> {:?}", i, chunk, result);
+            results.push(result);
+        }
+
+        let final_result: String = results.join("");
+        println!("Final result: {:?}", final_result);
+
+        // The truncated JSON should be discarded when the complete one appears
+        // Both JSONs should be filtered out, leaving only the text
+        let expected = "Some text\n\nMore text";
+        assert_eq!(
+            final_result, expected,
+            "Failed to handle truncated JSON followed by complete JSON"
+        );
+    }
 }