Metaworld

Meta-World is an open source benchmark for developing and evaluating multi-task and meta reinforcement learning algorithms for continuous control robotic manipulation environments, with various benchmarks to evaluate different aspects of reinforcement learning algorithms.

The documentation website is at metaworld.farama.org, and we have a public discord server (which we also use to coordinate development work) that you can join here: https://discord.gg/bnJ6kubTg6

Installation

To install Meta-World, use pip install metaworld

We support and test for Python 3.11, 3.12, and 3.13 on Linux and macOS. We will accept PRs related to Windows, but do not officially support it.

API

The Meta-World API follows the Gymnasium API for environment creation and environment interactions.

To create a benchmark and interact with it:

import gymnasium as gym
import metaworld


env = gym.make("Meta-World/MT1", env_name="reach-v3")

observation, info = env.reset()
for _ in range(500):
    action = env.action_space.sample()
    observation, reward, terminated, truncated, info = env.step(action)

env.close()

Available Benchmarks

Multi-Task Benchmarks

The MT1, MT10, and MT50 benchmarks are the Multi-Task Benchmarks. These benchmarks are used to learn a multi-task policy that can learn 1, 10, or 50 training tasks simultaneously. MT1 benchmarks can be created with any of the 50 tasks available in Meta-World. In the MT10 and MT50 benchmarks, the observations returned by the benchmark will come with one-hot task IDs appended to the state.

Meta-Learning Benchmarks

The ML1, ML10, and ML45 benchmarks are 3 meta-reinforcement learning benchmarks available in Meta-World. The ML1 benchmark can be used with any of the 50 tasks available in Meta-World. The ML1 benchmark tests for few-shot adaptation to goal variations within a single task. The ML10 and ML45 both test few-shot adaptation to new tasks. ML10 comprises 10 train tasks with 5 test tasks, while ML45 comprises of 45 training tasks with 5 test tasks.

Creating Multi-Task Benchmarks

MT1

import gymnasium as gym
import metaworld

seed = 42 # for reproducibility

env = gym.make('Meta-World/MT1', env_name='reach-v3', seed=seed) # MT1 with the reach environment

obs, info = env.reset()

a = env.action_space.sample() # randomly sample an action
obs, reward, truncate, terminate, info = env.step(a) # apply the randomly sampled action

MT10

MT10 has two different versions that can be returned by gym.make. The first version is the synchronous version of the benchmark where all environments are contained within the same process. For users with limited compute resources, the synchronous option needs the least resources.

import gymnasium as gym
import metaworld

seed = 42

envs = gym.make_vec('Meta-World/MT10', vector_strategy='sync', seed=seed) # this returns a Synchronous Vector Environment with 10 environments

obs, info = envs.reset() # reset all 10 environments

a = env.action_space.sample() # sample an action for each environment

obs, reward, truncate, terminate, info = envs.step(a) # step all 10 environments

Alternatively, for users with more compute we also provide the asynchronous version of the MT10 benchmark where each environment is isolated in it’s own process and must use inter-process messaging via pipes to communicate.

envs = gym.make_vec('Meta-World/MT10', vector_strategy='async', seed=seed) # this returns an Asynchronous Vector Environment with 10 environments

MT50

MT50 also contains two different versions, a synchronous and an asynchronous version, of the environments.

import gymnasium as gym
import metaworld

seed = 42

envs = gym.make_vec('Meta-World/MT50', vector_strategy='sync', seed=seed) # this returns a Synchronous Vector Environment with 50 environments

obs, info = envs.reset() # reset all 50 environments

a = env.action_space.sample() # sample an action for each environment

obs, reward, truncate, terminate, info = envs.step(a) # step all 50 environments

envs = gym.make_vec('Meta-World/MT50', vector_strategy='async', seed=seed) # this returns an Asynchronous Vector Environment with 50 environments

Meta-Learning Benchmarks

Each Meta-reinforcement learning benchmark has training and testing environments. These environments must be created separately as follows.

ML1

import gymnasium as gym
import metaworld

seed = 42


train_envs = gym.make('Meta-World/ML1-train', env_name='reach-V3', seed=seed)
test_envs = gym.make('Meta-World/ML1-test', env_name='reach-V3', seed=seed)

# training procedure use train_envs
# testing procedure use test_envs

ML10

Similar to the Multi-Task benchmarks, the ML10 and ML45 environments can be run in synchronous or asynchronous modes.

import gymnasium as gym
import metaworld

train_envs = gym.make_vec('Meta-World/ML10-train', vector_strategy='sync', seed=seed) # or vector_strategy='async'
test_envs = gym.make_vec('Meta-World/ML10-test', vector_strategy='sync', seed=seed) # or vector_strategy='async'

ML45

import gymnasium as gym
import metaworld

train_envs = gym.make_vec('Meta-World/ML45-train', vector_strategy='sync', seed=seed) # or vector_strategy='async'
test_envs = gym.make_vec('Meta-World/ML45-test', vector_strategy='sync', seed=seed) # or vector_strategy='async'

Custom Benchmarks

Finally, we also provide support for creating custom benchmarks by combining any number of Meta-World environments.

The prefix ‘mt’ will return environments that are goal observable for Multi-Task reinforcement learning, while the prefix ‘ml’ will return environments that are partially observable for Meta-reinforcement learning. Like the included MT and ML benchmarks, these environments can also be run in synchronous or asynchronous mode. In order to create a custom benchmark, the user must provide a list of environment names with the suffix ‘-v3’.

import gymnasium as gym
import metaworld

envs = gym.make_vec('Meta-World/custom-mt-envs',vector_strategy='sync', envs_list=['env_name_1-v3', 'env_name_2-v3', 'env_name_3-v3'], seed=seed) # or vector_strategy='async'
envs = gym.make_vec('Meta-World/custom-ml-envs',vector_strategy='sync', envs_list=['env_name_1-v3', 'env_name_2-v3', 'env_name_3-v3'], seed=seed) # or vector_strategy='async'

Development Roadmap

We have a roadmap for future development work for Gymnasium available here: https://github.com/Farama-Foundation/Metaworld/issues/500

Benchmark Code

Code for producing results found in the paper can be found at: https://github.com/rainx0r/metaworld-algorithms

Citation

You can cite Meta-World using our related paper (https://openreview.net/forum?id=1de3azE606) as:

@inproceedings{
mclean2025metaworld,
title={Meta-World+: An Improved, Standardized, {RL} Benchmark},
author={Reginald McLean and Evangelos Chatzaroulas and Luc McCutcheon and Frank R{\"o}der and Tianhe Yu and Zhanpeng He and K.R. Zentner and Ryan Julian and J K Terry and Isaac Woungang and Nariman Farsad and Pablo Samuel Castro},
booktitle={The Thirty-ninth Annual Conference on Neural Information Processing Systems Datasets and Benchmarks Track},
year={2025},
url={https://openreview.net/forum?id=1de3azE606}
}