# 04 — Limitations

From primary blog / card (as of 2026-07-21). Do not invent extra failure modes.

## Stated limitations

1. **Harness overfitting** (phrase: harness overfitting)  
   May recall native `pool` tool schemas instead of third-party definitions on first use (e.g. Hermes Agent terminal tool with slight schema drift). Usually fixed by in-context retry if the harness rejects the bad call.

2. **Nested tool calls / JSON args**  
   Tool format is XML-style:

   ```xml
   <tool_call>terminal<arg_key>cmd</arg_key><arg_value>uname -a</arg_value></tool_call>
   ```

   When an argument expects a **JSON array**, the model may emit incorrectly escaped or invalid JSON.

3. **Overthinking**  
   Long monologues before progress, especially competition math. Future: effort control + efficiency work.

4. **Effort control**  
   Only **off / max** at launch (default max). No low/medium/high dial.

5. **Modality**  
   Text-to-text only. No native vision (browser case study used external measurement tricks — headless Chromium, numerical screenshot compare).

## Eval / reporting caveats

| Caveat | Detail |
|---|---|
| Harness mismatch | Scores in **pool**; peers often native harness or third-party max |
| DeepSWE | Leaderboard uses mini-swe-agent; Poolside reports pool |
| Internet / reward hack | SWE family needed anti-solution-copy prompts mid training |
| Active params of peers | Tables may list secondary actives (e.g. Kimi A50B) — cross-check primaries |

## Production tips

- Prefer **pool** or ACP clients for best behavior  
- Keep **preserved thinking** (`reasoning_content`) multi-turn  
- Use official tool/reasoning parsers (`poolside_v1` / `laguna`)  
- Validate tool schemas with reject-and-retry loops  
- Quantize for single-node; plan multi-GPU for BF16 (~236 GB)  
- For third-party harnesses: expect first-call schema drift; log and retry  

## Open / planned (not limitations, but gaps)

- Configurable thinking effort  
- Base (pre-SFT) weights on request only  
- Larger next Laguna (pretrain already started per blog)