NLU Workbench properties
Summarize
Summary of NLU Workbench properties
The NLU Workbench properties enable ServiceNow customers to configure and optimize the Natural Language Understanding (NLU) application for improved intent classification, vocabulary management, and model training. These system properties are accessible by users with theadminornluadminrole via the path:All > NLU Workbench > Settingsin the application navigator.
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Key Features
- Model Settings: Control parameters such as the maximum number of utterances per intent (default 200, recommended less than 200 for balanced intent sizes), and limits on vocabulary sources:
- Table vocabulary source records capped at 100,000
- List vocabulary source values capped at 1,000
- Pre-built Vocabulary: Enable recognition of software and hardware names by toggling pre-built vocabulary features.
- Advanced Settings:
- Intent Discovery classification record limits (minimum 10,000, recommended below 500,000 for quality results)
- Minimum records for NLU performance analysis set at 5,000 for reliable insights
- Conflict detection thresholds for NLU model tuning with moderate (.85) and critical (.95) levels
- Batch test import file row limits set at 10,000 to ensure manageable testing sizes
- Limits on the number of utterances for feedback display and model tuning in the Expert Feedback Loop, including a minimum of 100 utterances reviewed before tuning
- Maximum fetch size for Virtual Agent chat logs is 3,000 by default, which can be increased up to 50,000 for high NLU usage scenarios
- Size limits on label candidate and labeled data tables capped at 10,000 entries to maintain performance during pruning
- Option to schedule NLU model training during off-peak hours to avoid instance blocking, with notification upon completion
Practical Guidance
- Maintain utterances per intent under 200 to keep models balanced.
- Keep vocabulary source sizes within recommended limits to ensure performance.
- Use sufficient data volumes (at least 10,000 records) for Intent Discovery to achieve high-quality classification results.
- Leverage pre-built vocabularies to improve entity recognition for software and hardware terms.
- Monitor NLU conflict detection thresholds to fine-tune model accuracy.
- Use the Expert Feedback Loop to collect and review at least 100 user utterances before tuning to enhance model precision.
- Consider increasing Virtual Agent chat log data fetch size if your instance has heavy NLU usage to improve feedback quality.
- Enable scheduled model training to minimize impact on instance performance during peak times.
Refer to these system properties for the Natural Language Understanding (NLU) application.
NLU Workbench properties and their usage
To access your system properties, use the admin or nlu_admin role and the following path in the application navigator: .
| Label and Name | Default value | Plugin | Recommended usage |
|---|---|---|---|
| Maximum number of utterances per
intent glide.nlu.utterances_per_intent.value_limit |
200 | NLU Workbench | Use fewer than 200 utterances per intent to keep your model
well balanced in terms of intent size. Note: Value must be
greater than 5 and less than or equal to 300. |
| Maximum number of records in a Table vocabulary
source glide.platform_ml.api.max_nlu_lookupsource_records |
100,000 | NLU Workbench | Keep the value under 100,000. |
| Maximum number of values in a List vocabulary
source glide.nlu.static_lookup.value_limit |
1,000 | NLU Workbench | Keep the value under 1,000. |
| Enable pre-built vocabulary for software
names glide.mlpredictor.option.nlu.@LookupSources:software |
enabled | NLU Workbench | Enable pre-built vocabulary so the system can recognize software names. |
| Enable pre-built vocabulary for hardware
names glide.mlpredictor.option.nlu.@LookupSources:hardware |
enabled | NLU Workbench | Enable pre-built vocabulary so the system can recognize hardware names. |
| Label and Name | Default value | Plugin | Recommended usage |
|---|---|---|---|
| Maximum number of records for Intent Discovery
classification sn_nlu_discovery.intent_discovery_max_classification_limit |
300,000 | Intent Discovery | Keep the number of records less than 500,000. |
| Minimum number of records for Intent Discovery
classification sn_nlu_discovery.intent_discovery_min_classification_limit |
10,000 | Intent Discovery | Use at least 10,000 records to get high quality results. |
| Minimum number of records for NLU performance
analysis sn_nlu_workbench.glide.nlu.performance.min_clustering_records |
5,000 | NLU Workbench - Advanced Features | Use at least 5,000 records to get high quality results. |
| NLU Conflict Detection - Moderate
Threshold sn_nlu_workbench.glide.nlu.conflict.moderate_threshold |
.85 | NLU Workbench - Advanced Features | Must be a decimal between 0 and 1. Keep this threshold less than the Critical Threshold. |
| NLU Conflict Detection - Critical
Threshold sn_nlu_workbench.glide.nlu.conflict.critical_threshold |
.95 | NLU Workbench - Advanced Features | Must be a decimal between 0 and 1. Keep this threshold greater than the Moderate Threshold. |
| The maximum number of rows in a batch test import
file sn_nlu_workbench.glide.nlu.batch_test.max_import_rows |
10,000 | NLU Workbench - Advanced Features | Make sure your batch test import file has no more than 10,000 rows. |
| The maximum number of utterances to display for feedback in
the expert feedback
loop glide.mlpredictor.option.nlu.activeLearning.label_candidate_table.max_response_size |
300 | NLU Workbench - Advanced Features | Pull no more than 300 utterances from your users' Virtual Agent chat logs to display for feedback in the Expert Feedback Loop application.The minimum umber of utterances a user should review before tuning the model |
| The minimum number of utterances a user should review before
tuning the
model sn_nlu_workbench.glide.nlu.optimize.min_labeled_data |
100 | NLU Workbench - Advanced Features | Provide and save feedback for at least 100 utterances from your users' Virtual Agent chat logs so you can execute the Tune Model feature in the Expert Feedback Loop application. |
| The maximum number of records to fetch from Virtual Agent chat
logs glide.mlpredictor.option.nlu.activeLearning.va_chat_logs.max_row_limit - 3000 |
3,000 | NLU Workbench - Advanced Features | If there is high NLU usage, increasing the default value to a maximum of 50,000 records will increase the data available for the active learning job to filter up on and display in the Expert Feedback Loop application to give feedback on. |
| Size limit on Label Candidate Table (used for pruning the
table) glide.mlpredictor.option.nlu.activeLearning.label_candidate_table.max_data_size - 10000 |
10,000 | NLU Workbench - Advanced Features | The recommended usage for this property is the same as the property above. |
| Size limit on Labeled Data Table (used for pruning the
table) glide.mlpredictor.option.nlu.activeLearning.label_table.max_data_size - 10000 |
10,000 | NLU Workbench - Advanced Features | The recommended usage for this property is the same as the property above. |
| Enable this property to unblock your instance during NLU model training. The training will be scheduled for an off-peak time, and we will notify you when it's done.
glide.mlpredictor.scheduled.nlu.model.training |
False | NLU Workbench - Advanced Features | False |
To get more feedback data from Virtual Agent (VA) chat logs, refer to the Procuring additional VA feedback data on demand section in the Expert Feedback Loop documentation.