ErrLookup › Unity-Technologies/ml-agents
Unity-Technologies/ml-agents
The Unity Machine Learning Agents Toolkit (ML-Agents) is an open-source project that enables games and simulations to serve as environments for training intelligent agents using deep reinforcement learning and imitation learning. · C# · 481 source files
Analyzed at 3ecb446f75 on 2026-09-02. 143 documented errors.
| Code / Message | Type | Severity | Tags |
|---|---|---|---|
| When using a recurrent network, memory size must be… | validation | error | config, recurrent-network, lstm, validation |
| Workers stuck in waiting state | exception | error | |
| Unknown reward signal type | exception | error | |
| Invalid trainer type | validation | error | config, ml-agents |
| Trying to export an attention mechanism that doesn't have a… | exception | error | |
| Index out of bounds, expected a number between 0 and | exception | error | unity, ml-agents, index-out-of-range, actions |
| Cannot move cell at row= | exception | error | unity, ml-agents, match3, index-out-of-range, edge-move, bounds |
| The reward provider's update method has not been… | exception | error | |
| UnityEnvironment worker: send failed. | exception | error | |
| The trainer was unable to process any of the provided… | exception | error | python, mlagents, configuration, sensors |
| Demonstration import error. | exception | error | unity, editor, asset-import, demonstration |
| The option was specified in your YAML file, but is invalid. | validation | error | |
| Unsupported reward signal configuration | validation | error | config, yaml, reward-signals, validation |
| UnityEnvironment worker: recv failed. | exception | error | |
| The DefaultTrainingAnalyticsSideChannel received a message… | exception | error | unity, side-channel, version-mismatch |
| If the environment name is None, the worker-id must be 0 in… | exception | error | configuration, editor-connection, worker-id |
| The reward provider's evaluate method has not been… | exception | error | |
| The option was specified in your YAML file for , but is… | validation | error | ml-agents, configuration, yaml, schema-validation, typo |
| No parent indices set | exception | error | unity, ml-agents, null-reference, sensor, initialization-order |
| Config doesn't specify a trainer type. Please specify… | exception | error | python, ml-agents, config, yaml, trainer-type |
| Could not initialize from | exception | error | ml-agents, file-not-found, checkpoint-loading, configuration |
| There was a problem reading a message in a SideChannel… | exception | error | unity, python, ml-agents, side-channel, version-mismatch, serialization |
| The communication API version is not compatible between… | exception | error | version-mismatch, protocol, ml-agents |
| num_areas must be set to a positive number >= 1. | validation | error | |
| __str__ not implemented for type | exception | warning | api-misuse, parameter-randomization, string-formatting |
| The one of the goals uses variable length observations… | exception | error | python, mlagents, unsupported-feature, entity-embeddings |
| Error when trying to launch environment - make sure… | exception | error | permissions, subprocess, environment-launch |
| Visual observation resolution | exception | error | python, mlagents, visual-observations, resolution, config |
| Unsupported config for . | validation | error | ml-agents, configuration, yaml, schema-validation, type-error |
| GetCompressedObservation() returned null data for sensor… | exception | error | unity, ml-agents, sensor, compression, null-reference |
| The shape for observation in demonstration do not match the… | exception | error | ml-agents, demonstrations, shape-mismatch, imitation-learning |
| Can't use Behavior Type | exception | critical | unity, ml-agents, configuration, inference |
| agent_id is did not request a decision at the previous step | exception | error | agent-id, decision-steps, validation |
| Invalid Compressed Channel Mapping: the mapping | exception | error | python, unity-ml-agents, observation, protocol-mismatch |
| agent_id is not present in the TerminalSteps | exception | error | python, ml-agents, keyerror, terminal-steps, agent-lifecycle |
| Communicator has exited. | exception | error | environment-crashed, communicator, process-exited |
| Couldn't launch the environment. Provided filename does not… | exception | error | python, ml-agents, environment-launch, file-not-found, executable |
| Couldn't start socket communication because worker number | exception | error | python, unity-ml-agents, port-in-use, network |
| StatsSideChannel should never receive messages. | exception | error | unity, python, ml-agents, side-channel, contract-violation, stats |
| The path provided is not a '.demo' file. | exception | error | ml-agents, file-path, demonstrations, valueerror |
| Variable Length Observations are not supported by the… | exception | error | unity, ml-agents, trainer-compatibility, observation, version-mismatch |
| Continuous NaN action detected. | exception | critical | ml-agents, nan, numerical-instability, training-divergence |
| The demonstrations do not have the same number of… | exception | error | ml-agents, demonstrations, observation-mismatch, imitation-learning |
| The folder containing the generated model could not be… | exception | error | python, mlagents, filesystem, permissions, output-path |
| Metadata not found, resuming from an incompatible version… | exception | error | python, ml-agents, resume, checkpoint-incompatible |
| The actions in demonstration do not match the policy's . | exception | error | runtimeerror, ml-agents, demonstrations, action-space-mismatch |
| Inf found | exception | critical | ml-agents, sac, nan, inf, training-divergence |
| The group does not correspond to an existing agent group in… | exception | error | behavior-name, agent-group, validation |
| Your final lesson definition contains completion_criteria… | console | warning | python, ml-agents, curriculum, lesson, config-warning |
| called recursively. This might happen if you call… | exception | critical | unity, ml-agents, recursion, environment-step |
| SAC does not support SharedActorCritic | exception | error | ml-agents, configuration, sac, incompatible-options |
| Compressed observation and its mapping had different number… | exception | error | python, unity-ml-agents, observation, protocol-mismatch |
| The batch size and training length requested for get_batch… | exception | error | training, buffer, rl, hyperparameters |
| Unsupported Sensor with specs | exception | error | python, mlagents, observations, unsupported-sensor |
| When using a recurrent network, memory size must be greater… | validation | error | ml-agents, configuration, validation, lstm, yaml |
| A side channel with id | exception | error | unity, ml-agents, side-channel, duplicate-registration, guid |
| There was a problem reading a message in a SideChannel… | exception | error | unity, side-channel, version-mismatch, protocol |
| agent_id is not present in the DecisionSteps | exception | error | python, ml-agents, keyerror, decision-steps, agent-lifecycle |
| The TrainingAnalyticsSideChannel received a message from… | exception | error | python, mlagents, side-channel, version-mismatch, communication |
| Can't load Demonstration data from an unsupported version | exception | error | ml-agents, demonstrations, version-incompatibility, serialization |
| {failedCheck.Message} | exception | error | unity, ml-agents, sentis, model-validation, shape-mismatch |
| row was , but must be between 0 and . | exception | error | unity, ml-agents, match3, index-out-of-range, bounds |
| Config doesn't specify use_recurrent. Please specify true… | exception | error | python, ml-agents, config, yaml, use-recurrent |
| The trainer config contains an unknown trainer type | exception | error | python, mlagents, config-validation, trainer-type |
| The behavior needs a continuous input of dimension for ( … | validation | error | python, ml-agents, action-space, shape-mismatch, validation |
| Trainer was unable to process any of the goals provided as… | exception | error | python, mlagents, configuration, empty-input |
| Unknown tensorProxy expected as input | exception | error | unity, ml-agents, inference, tensor, naming-mismatch |
| The BufferSensor was expecting an observation of size | exception | error | unity, ml-agents, sensors, buffer-sensor, shape-mismatch |
| Enumerator not started. | exception | error | unity, ml-agents, enumerator, invalid-operation |
| NotImplementedError | exception | error | python, mlagents, abstract-method, custom-trainer |
| The schedule is invalid. | exception | error | python, mlagents, config-validation, hyperparameters |
| Unknown StatsAggregationMethod encountered. | exception | error | trainer, stats, version-mismatch |
| Action spaces with both continuous and discrete actions are… | exception | error | unity, ml-agents, action-space, configuration |
| Sampler configuration does not contain sampler_parameters | validation | error | config, yaml, parameter-randomization, missing-key |
| Previous data from this run ID was found. Either specify a… | exception | error | ml-agents, trainer, output-directory, run-id |
| GridSensorComponent received no sensors. Specify at least… | exception | error | unity, ml-agents, grid-sensor, configuration, empty-list |
| No BrainParameters found in demonstration file at | exception | error | ml-agents, demonstrations, corrupt-file, serialization |
| shape and dimensionProperties must have the same length. | validation | error | unity, ml-agents, observation-spec, shape-mismatch, api-misuse |
| Expected parentIndices[0] to be -1, got | validation | error | unity, ml-agents, validation, hierarchy, debug-assert |
| Registering Object of unsupported type | exception | error | ml-agents, type-error, pytorch, api-misuse |
| No Unity environment is loaded. | exception | error | lifecycle, environment, reset |
| Previous data from this run ID was not found. Train a new… | exception | error | ml-agents, trainer, resume, run-id |
| The behavior name has not been specified in the trainer… | validation | error | config, ml-agents |
| Call to SendInfoToBrain when Agent hasn't been… | exception | error | unity, ml-agents, agent, initialization-order |
| Agent is already registered with a group. Unregister it… | exception | error | unity, ml-agents, agent, group-management |
| API versions of demonstration are incompatible. | exception | error | unity, ml-agents, demonstration, version-mismatch |
| Threshold for next lesson cannot be negative when the… | validation | error | config, curriculum, ml-agents |
| When using compression type | exception | error | unity, ml-agents, grid-sensor, normalization, compression |
| Decompressed observation did not have the expected shape -… | exception | error | python, unity-ml-agents, observation, compression, shape-mismatch |
| The provided had Infinite values. | exception | error | python, unity-ml-agents, infinity, numerical |
| Unsupported parameter randomization configuration | validation | error | config, yaml, parameter-randomization, validation |
| The EngineConfigurationChannel received a message from… | exception | error | unity, side-channel, version-mismatch |
| channel value must be in range [0, ] | validation | error | unity, ml-agents, observation-writer, bounds, index-out-of-range |
| The behavior needs a discrete input of dimension for ( , )… | validation | error | python, ml-agents, action-space, shape-mismatch, discrete-actions |
| Config file could not be found at | exception | error | config, file-not-found, ml-agents, cli |
| Observation at index= | exception | error | python, unity-ml-agents, observation, shape-mismatch |
| There can only be one behavior in a UnityEnvironment if it… | exception | error | gym, unity-environment, configuration |
| Enumerator has reached the end already. | exception | error | unity, ml-agents, enumerator, invalid-operation |
| Observation did not have the expected shape - got | exception | error | python, unity-ml-agents, observation, shape-mismatch |
| Error parsing yaml file. Please check for formatting… | exception | error | config, yaml, parse-error, ml-agents |