---
title: "TRACER: Early Failure Detection for — Nourbakhsh 2026"
description: "Most evaluation of task-oriented dialogue (TOD) systems judges a conversation only after it ends, when it is too late to rescue it."
authors: ["Erfan Nourbakhsh", "Rocky Slavin", "Ke Yang", "Anthony Rios"]
year: 2026
venue: "Proceedings of the 27th Annual Meeting of the Special Interest Group on Discourse and Dialogue"
source: "https://aclanthology.org/2026.sigdial-1.44/"
doi: "10.18653/v1/2026.sigdial-1.44"
licence: "CC BY 4.0 (ACL Anthology)"
licence_url: "https://creativecommons.org/licenses/by/4.0/"
summary_licence: "Elamur Cosmic License"
canonical: "https://research.elamur.ai/free/en/papers/nourbakhsh-2026-tracer-early-failure-detection-task/"
---
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# TRACER: Early Failure Detection for Task-Oriented Dialogue

**Authors:** Erfan Nourbakhsh, Rocky Slavin, Ke Yang, [Anthony Rios](https://md.research.elamur.ai/free/en/authors/anthony-rios/) · **Year:** 2026 · **Venue:** Proceedings of the 27th Annual Meeting of the Special Interest Group on Discourse and Dialogue · **Licence:** [CC BY 4.0 (ACL Anthology)](https://creativecommons.org/licenses/by/4.0/)

**Links:** [Publisher's page](https://aclanthology.org/2026.sigdial-1.44/) · [PDF](https://aclanthology.org/2026.sigdial-1.44.pdf) · [DOI 10.18653/v1/2026.sigdial-1.44](https://doi.org/10.18653/v1/2026.sigdial-1.44) · [OpenAlex](https://openalex.org/W7167585477)

**Citations:** 0 citations (OpenAlex, 2026-10-14)

## Summary
Most evaluation of task-oriented dialogue (TOD) systems judges a conversation only after it ends, when it is too late to rescue it. TRACER reframes this as forecasting: given only a prefix of a dialogue, it estimates the probability that the whole interaction will fail. Each visible prefix becomes a separate training example labeled with the dialogue's final outcome. The model has two input streams. One encodes the serialized belief state as text with RoBERTa. The other processes a sequence of turn-level trajectory features describing how the dialogue state evolves. The fused representation produces a risk score, and a threshold tuned on development data decides when to launch a recovery action. Experiments use both gold (oracle) and LLM-generated belief states, showing the model 25%, 50%, 75% or 100% of each dialogue. TRACER finds useful failure signals as early as the first quarter of a conversation. It outperforms heuristic, classical and single-stream baselines. This makes early warning a practical tool for live dialogue systems rather than a post-hoc diagnostic.

## Key points
- The trajectory stream uses a 5-dimensional vector per turn:
  - oscillation score (slots whose values keep changing),
  - coverage rate of required slots,
  - cumulative conflict count,
  - fill velocity,
  - number of domains visited.
- The text stream encodes the cumulative belief state with RoBERTa, serialized as "domain-slot: value" pairs following the MultiWOZ ontology.
- In the generated setting, belief states are predicted turn by turn by Qwen3-30B-A3B instead of being taken from gold annotations.
- Zero-shot baselines prompt Llama-3.1-8B, Mistral-7B-Instruct and Qwen2.5-7B to output a JSON success/failure prediction with a confidence score, which is mapped to a failure probability for AUC.
- For recovery, a feature-driven template method beats a fine-tuned T5 generator at targeting the actual source of instability, even though T5 produces fluent text. Code is available at github.com/erfan-nourbakhsh/TRACER.

*Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.*

Fields: [Linguistics & languages](https://md.research.elamur.ai/free/en/shelves/linguistics/)

Topics: [Dialogue systems](https://md.research.elamur.ai/free/en/topics/dialogue-systems/)

## Institutions

Also on the byline: [The University of Texas at San Antonio](https://ror.org/01kd65564).

## Cite

The paper itself, not this page. BibTeX from the library's record of the work.

```bibtex
@inproceedings{nourbakhsh2026tracer,
  title = {{TRACER: Early Failure Detection for Task-Oriented Dialogue}},
  author = {Nourbakhsh, Erfan and Slavin, Rocky and Yang, Ke and Rios, Anthony},
  booktitle = {Proceedings of the 27th Annual Meeting of the Special Interest Group on Discourse and Dialogue},
  year = {2026},
  doi = {10.18653/v1/2026.sigdial-1.44},
  url = {https://doi.org/10.18653/v1/2026.sigdial-1.44}
}
```

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