Constraint And Satisfiability-based Planning: an Exploratory Research Workshop (CASP:ER 2026)

Despite the widespread adoption of heuristic search and learning-based approaches in automated planning, Constraint and Satisfiability-based Planning (CSP/SAT-based Planning) remains a viable and promising paradigm. Historically, CSP and SAT approaches have demonstrated strong theoretical foundations and practical success in various domains. However, their usage has diminished in recent years due to the rise of alternative methods. The CASP:ER workshop aims to revisit and reinforce the relevance of CSP/SAT-based planning by showcasing recent advancements, discussing its applicability, and identifying opportunities for renewed adoption.

A surge of research on the topic of CSP/SAT-based planning in recent years has proven that it is far from obsolete. Advances in constraint programming, SAT solvers, and hybrid methodologies suggest that these techniques still have much to offer. The objectives of the workshop are thus as follows: (i) highlight recent breakthroughs in CSP/SAT-based planning and their impact on the field, (ii) explore novel applications where constraint-based planning remains competitive or superior, (iii) foster discussions on integrating CSP/SAT methods with modern AI approaches, such as machine learning and heuristic search (iv) bring together researchers and practitioners interested in constraint-based reasoning for planning, and (v) identify key challenges and future research directions that can rejuvenate interest in CSP/SAT-based planning.

This year’s edition is the second edition of CASP:ER – the first one was held at ICAPS 2025.

Important Dates

This year’s second edition of CASP:ER will be held on June 28th or 29th, 2026, as a workshop co-located with ICAPS 2026. Important dates

• Paper submission: April 27th May 5th, 2026 May 12th, 2026
• Notification: May 25th, 2026
• Camera-ready: June 1st, 2026
• Workshop: June 28th or 29th, 2026

Call for contributions

We invite contributions on various topics related to CSP/SAT-based planning. In order to lower the barrier to participation and acknowledge the increasing pressure on researchers to submit full papers to conferences, the CASP:ER workshop adopts a lightweight submission format. We require submissions in the form of short or extended abstracts, intended primarily to support a presentation and discussion at the workshop rather than a full archival publication. Submissions will be evaluated based on their relevance, novelty, and potential to stimulate discussion, rather than through a full peer-review process. We believe this format will encourage timely and exploratory contributions and foster a more open and interactive workshop environment.

Topics of interest include, but are not limited to:

1. Advances in constraint programming and sat solving for planning problems.
2. Hybrid approaches of csp/sat with heuristic search or reinforcement learning.
3. Scalability improvements in constraint-based planning methods.
4. Applications of csp/sat-based planning in real-world scenarios.
5. Comparisons between csp/sat-based planning and alternative paradigms.
6. Explainability and interpretability in constraint-based planning solutions.
7. Benchmarks, datasets, and evaluation methodologies for csp/sat-based planning.
8. Learning techniques aiding and helping csp/sat-based planning approaches.

Submitted papers should use the AAAI Author Kit. Short abstracts should not be longer than 1 page (plus references). Extended abstracts should not be longer than 4 pages (plus references). Submissions must be anonymous.

Submissions must be in PDF format and will be handled via the EasyChair Conference system.

Accepted Papers

• A Comparison of Unsolvability Certificates in Planning and Model Checking
  Malte Helmert and Tanja Schindler
• An Automata-Based Constraint Programming Framework for Optimal Classical Planning (Extended Abstract)
  Damien Van Meerbeeck, Arnaud Lequen, Gilles Pesant and Jendrik Seipp
• CP-WSP: A Declarative CP-SAT Framework for Configurable Multi-Constraint Workforce Scheduling
  Vipul Patel, Anirudh Deodhar and Dagnachew Birru
• Guiding CP Search for Recurring Vehicle Routing Problems with Learned Heuristics
  Marc-Emmanuel Coupvent des Graviers, Jeremy Turi and Christophe Guettier
• Learning Heuristics to Solve Routing Problems Increasingly Faster
  Marc-Emmanuel Coupvent des Graviers, Jeremy Turi and Christophe Guettier
• Transforming and Encoding FTS for SAT Solving: What Helps, What Hurts
  João Felipe, Álvaro Torralba and Gregor Behnke
• Lifted Planning as SMT
  Miquel Bofill, Cristina Borralleras and Josu Oca
• Towards Qualitative Constraint-Based HTN Planning: A Research Agenda
  Tobias Schwartz, Christopher Walther and Diedrich Wolter
• Leveraging CP for Numeric-to-Classical Planning Compilations
  Carla Davesa Sureda, Joan Espasa Arxer, Ian Miguel and Mateu Villaret
• An Insertion-Based Linked List Variable and Regular Constraint for Classical Planning with Constraint Programming
  Damien Van Meerbeeck
• Planning and Scheduling, What’s the Difference Anyway?
  Arthur Bit-Monnot

Workshop Schedule

Program Committee Chairs

• Gregor Behnke - University of Amsterdam
• Matteo Cardellini - University of Genova
• Nicola Gigante - Free University of Bozen-Bolzan
• Andrea Micheli - Fondazione Bruno Kessler

Contacts

For more information email to any of the program chairs at casper2026@easychair.org