The Automated Negotiating Agents Competition at IJCAI 2026: Human-Agent Negotiation League

[Tim Baarslag]

### Call for Submissions

You are invited to submit a negotiating agent to the **Human-Agent Negotiation (HAN) League** of the
International Automated Negotiating Agents Competition (ANAC) as part of the IJCAI 2026
official competition track. Please see:

https://anac.cs.brown.edu/han

ANAC has been running since 2010 in conjunction with AAMAS/IJCAI. The HAN league focuses
on the specific challenges facing an agent negotiating with a human partner instead of
another agent.

### The Challenge

The participants are challenged to build a negotiation strategy that uses the alternating
offers protocol (AOP) augmented with text input/output to effectively negotiate with human
subjects. Strategies should be compatible with standard AOP but may use multi-modal
communication to influence or inform the human negotiator.


### Negotiation Protocol

Agents act as negotiators in a bilateral setting. The protocol follows these rules:

* **Alternating Offers**: Negotiators take turns making offers. On each turn, the negotiator (human or agent) can Accept, Reject (and counter), or End the negotiation.
* **Multi-modal Communication**: Agents can return Markdown-formatted text to provide context/offer or persuasion to the human partner. Moreover, the human partner can use free text for communication with the agent.
* **Scenario**: Different scenarios will be evaluated including Procurement, Resource Distribution, etc. Evaluation scenarios can differ from the examples provided in the submission template.

### Platform

The league is built on NegMAS (https://negmas.readthedocs.io/en/latest/), the same platform used for all ANAC 2026 leagues.

**Development**: Please download the template from https://anac.cs.brown.edu/files/han/y2026/han.zip and follow the installation steps in `README.md`

**API**: We provide multiple APIs that can be used to implement your agent:
 
  * You can implement a single `__call__()` method that receives an offer (containing text
    and/or proposal) and responds to it with a decision (accept/reject/end) and an
    optional counter offer (in case of rejection) with optional text.
  * You can modify the prompts used by an LLM to implement the negotiation strategy.
  * You can build your agent by combining existing or new offering strategies, acceptance
    strategies and opponent modeling methods.

A simple tutorial of how to implement and submit your agent can be found at https://anac.cs.brown.edu/files/han/y2026/template2026.pdf

### Competition Flow

The competition runs the following way:
    An *LLM round* will be conducted in which the participating agents negotiate against personality-adjusted
    verified LLM negotiators simulating human negotiators. Selected agents from the LLM round will then be evaluated against crowd-sourced human
    negotiators to select the finalists and then the winner(s).

### Evaluation

Agents are ranked based on the utility they achieve against a variety of human subjects. We will also evaluate agents based on the perception of human partners using questionnaires.

### Submission and Live Competition

- To participate in the competition, please register at https://anac.cs.brown.edu/register and download the official template from https://anac.cs.brown.edu/files/han/y2026/han.zip
- You can resubmit your agent as many times as you want until the deadline (with
  the same ID). Submitted agents will be used to run online tournaments which gives
  you feedback about the performance of your agent. Submitted code is never
  shared until the announcement of the winners.
- All submitted agents will be made publicly available after the announcement of the
  winners as per ANAC rules.
- You must accompany your final submission with a 2-pages academic report
  describing your agent which will also be made publicly available after the
  announcement of the winners.
 


### Organizing Committee

* **Yasser Mohammad**, NEC CORPORATION (main contact)
* **Reyhan Aydogan**, Özyeğin University & Delft University of Technology
* **Rafik Hadfi**, Kyoto University

### Important Dates

* **Registration on the competition website (Recommended)**: April 25th, 2026
* **Submission deadline**: June 1st, 2026
* **Academic Report submission deadline**: June 5th, 2026

### Sponsors

NEC CORPORATION