---
license: apache-2.0
tags:
  - text2sql
  - sql
  - unknown-schema
  - tool-use
  - reinforcement-learning
  - arxiv:2603.16448
---

# TrustSQL

**Tool-Integrated Multi-Turn Reinforcement Learning for Text-to-SQL over Unknown Schemas**

[![arXiv](https://img.shields.io/badge/arXiv-2603.16448-b31b1b.svg)](https://arxiv.org/abs/2603.16448)
[![GitHub](https://img.shields.io/badge/GitHub-TrustSQL-black?logo=github)](https://github.com/JaneEyre0530/TrustSQL)
[![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://www.apache.org/licenses/LICENSE-2.0)

TrustSQL (**T**ruthful **R**easoning with **U**nknown **S**chema via **T**ools) is an agentic Text-to-SQL framework for settings where the complete database schema is not pre-loaded into the model context. Instead of passively translating a question from a full schema dump, the agent actively explores the database, verifies relevant metadata, generates candidate SQL, and confirms the final answer.

## Highlights

- **Unknown Schema reasoning:** retrieve only the metadata needed for the current question.
- **Four-phase interaction protocol:** `Explore → Propose → Generate → Confirm`, with iterative refinement when more information is needed.
- **Phase-Aware GRPO:** separate schema-grounding and SQL-generation learning signals with token-level masked advantages.
- **Execution-coupled schema reward:** give schema credit when the proposed schema is correct and the resulting SQL executes correctly.
- **Multiple scales:** released checkpoints include 4B and 8B variants; the research results also report a 14B variant.

## Collection

| Type | Repository | Description |
|---|---|---|
| Model | [`AIJian/TrustSQL-4B`](https://huggingface.co/AIJian/TrustSQL-4B) | 4B TrustSQL checkpoint based on Qwen3-4B |
| Model | [`AIJian/TrustSQL-8B`](https://huggingface.co/AIJian/TrustSQL-8B) | 8B TrustSQL checkpoint based on Qwen3-8B |
| Dataset | [`AIJian/TrustSQL-data`](https://huggingface.co/datasets/AIJian/TrustSQL-data) | Training data for TrustSQL |
| Overview | [`AIJian/TrustSQL`](https://huggingface.co/AIJian/TrustSQL) | Project overview, results, usage, citation, and links |

## Results

All results below use the **Unknown Schema** setting, without pre-loaded database metadata. Execution Accuracy (EX) measures whether the generated SQL returns the same result as the reference query.

### BIRD-Dev

| Model | Greedy | Majority voting |
|---|---:|---:|
| TRUST-SQL-4B | 64.9 | 67.2 |
| TRUST-SQL-8B | 65.8 | 67.7 |
| TRUST-SQL-14B | 68.1 | 70.1 |

### Robustness and compositional benchmarks

| Model | Spider-Test | Spider-DK | Spider-Syn | Spider-Realistic |
|---|---:|---:|---:|---:|
| TRUST-SQL-4B | 82.8 / 85.0 | 71.6 / 73.8 | 74.7 / 77.3 | 79.9 / 82.5 |
| TRUST-SQL-8B | 83.9 / 86.5 | 72.1 / 75.7 | 75.4 / 77.4 | 82.1 / 84.1 |
| TRUST-SQL-14B | 83.9 / 86.5 | 75.0 / 78.6 | 78.4 / 79.7 | 82.7 / 86.5 |

Each entry is `Greedy / Majority voting`.

On BIRD-Dev, the framework improves over the corresponding base models by an average of **30.6 absolute points** for the 4B model and **16.6 absolute points** for the 8B model across the five evaluation benchmarks.

## How it works

### 1. Explore Schema

Use metadata tools to discover tables, columns, foreign keys, and relevant value patterns. Schema knowledge must come from verified tool observations rather than model memory.

### 2. Propose Schema

Commit to the currently verified tables and columns. This explicit checkpoint reduces schema hallucination and defines the boundary for schema-specific credit assignment.

### 3. Generate SQL

Generate and execute a candidate SQL query using the proposed schema. The execution result provides feedback for query refinement.

### 4. Confirm Answer

Return the final SQL answer after the schema and query have been validated. The workflow can revisit earlier phases when additional evidence is needed.

## Training

The TrustSQL training recipe uses a two-stage pipeline:

1. **SFT warm-up:** 9.2k structured demonstrations teach the interaction protocol.
2. **Phase-Aware GRPO:** 11.6k RL samples optimize schema exploration and SQL generation with separate masked advantages.

The method is implemented with the SLIME training framework. The experiments use Qwen3-4B, Qwen3-8B, and Qwen3-14B as base models.

## Usage

The checkpoints are intended for **tool-integrated multi-turn inference**, not ordinary one-shot text completion. At inference time, the host application should expose database metadata and SQL execution tools, then enforce the four-phase action protocol.

Minimal loading example:

```python
from transformers import AutoModelForCausalLM, AutoTokenizer

model_id = "AIJian/TrustSQL-8B"

tokenizer = AutoTokenizer.from_pretrained(model_id, trust_remote_code=True)
model = AutoModelForCausalLM.from_pretrained(
    model_id,
    torch_dtype="auto",
    device_map="auto",
    trust_remote_code=True,
)
```

For the complete action schemas, prompts, training configuration, and evaluation pipeline, see the project repository:

`https://github.com/JaneEyre0530/TrustSQL`

## Important limitations

- Training and reported evaluations use SQLite-based benchmarks.
- Inference requires access to the target database or a compatible metadata/execution environment.
- The current implementation uses a fixed interaction budget; highly complex databases may benefit from adaptive horizons.
- The reported benchmark numbers are research results and should not be interpreted as a guarantee for production workloads.

## Citation

```bibtex
@article{jian2026trustsql,
  title   = {TRUST-SQL: Tool-Integrated Multi-Turn Reinforcement Learning for Text-to-SQL over Unknown Schemas},
  author  = {Jian, Ai and Zhang, Xiaoyun and Du, Wanrou and Ruan, Jingqing and Pei, Jiangbo and Zhang, Weipeng and Zeng, Ke and Cai, Xunliang},
  journal = {arXiv preprint arXiv:2603.16448},
  year    = {2026},
  url     = {https://arxiv.org/abs/2603.16448}
}
```

## License

The released model and dataset repositories are marked as Apache-2.0. The dataset may contain material derived from third-party benchmarks; users are responsible for complying with the original benchmark licenses and usage terms.

## Contact

For questions or feedback, please open an issue in the project repository or contact `jianai@bupt.edu.cn`.