diff --git a/poc-memory/src/agents/knowledge.rs b/poc-memory/src/agents/knowledge.rs
index 03d3166..c77f7f2 100644
--- a/poc-memory/src/agents/knowledge.rs
+++ b/poc-memory/src/agents/knowledge.rs
@@ -143,6 +143,16 @@ fn run_one_agent_inner(
     // Rough estimate: 1 token ≈ 4 bytes. Reserve 16K tokens for output.
     let max_prompt_bytes = 800_000; // ~200K tokens, leaves room for output
     if agent_batch.prompt.len() > max_prompt_bytes {
+        // Log the oversized prompt for debugging
+        let oversize_dir = store::memory_dir().join("llm-logs").join("oversized");
+        fs::create_dir_all(&oversize_dir).ok();
+        let oversize_path = oversize_dir.join(format!("{}-{}.txt",
+            agent_name, store::compact_timestamp()));
+        let header = format!("=== OVERSIZED PROMPT ===\nagent: {}\nsize: {}KB (max {}KB)\nnodes: {:?}\n\n",
+            agent_name, prompt_kb, max_prompt_bytes / 1024, agent_batch.node_keys);
+        fs::write(&oversize_path, format!("{}{}", header, agent_batch.prompt)).ok();
+        log(&format!("oversized prompt logged to {}", oversize_path.display()));
+
         return Err(format!(
             "prompt too large: {}KB (max {}KB) — seed nodes may be oversized",
             prompt_kb, max_prompt_bytes / 1024,