NLU to LLM migration log

  • Release version: Zurich
  • Updated July 31, 2025
  • 5 minutes to read
    • Summarize
    Summarized using AI
    This content was generated using new OpenAI-powered functionality. Results are provided on an as is basis and are not guaranteed to be accurate or complete.

    Summary of NLU to LLM Migration Log

    The NLU to LLM migration log in ServiceNow tracks the process of migrating Natural Language Understanding (NLU) topics to large language model (LLM) topics. This log is accessible via theTopic Migration Execution Items [topicmigrationexecutionitem.list]table and provides detailed data on migration status, issues encountered, and information about migrated or published topics. Customers can review migration details either directly through the ServiceNow interface or by downloading the migration log as a CSV file during the migration workflow.

    Show full answer Show less

    Key Features

    • Topic Migration Execution Items Table: Displays columns such as Description, Issues, LLM Topic, Migration Execution ID, Migration Status, NLU Topic, and Status Type. Each Migration Execution ID corresponds to a batch of topics migrated together.
    • Issue Tracking: The Issues column highlights common migration problems categorized by node-level, script-level, topic-level, LLM-generated description issues, and migration process failures.
    • Publishing Guidance: The log indicates whether topics with specific issues can be published immediately or require manual corrections before publishing.

    Practical Guidance on Migration Issues

    Common migration issues and their impact on publishing include:

    • Node-Level Issues: Validation errors such as missing required fields. Topics cannot be published until corrected.
    • Script-Level Issues: Occur when NLU input nodes contain scripts or data pills in prompts. Topics can be published but require manual review and improvement of detailed descriptions.
    • Topic-Level Issues: Missing descriptions or keywords that block publishing until fixed.
    • LLM-Generated Description Issues: Occur when LLM cannot generate valid descriptions due to intent or keyword mapping problems. Topics can be published but descriptions should be revised manually.
    • Dynamic Topic Block and Switch Topic Script Issues: When dynamic blocks or switch scripts fail to migrate, topics remain functional using NLU blocks but require manual migration of those components.
    • Process Failure Issues: Critical errors during migration or transformation require ServiceNow support intervention and prevent publishing until resolved.
    • Description Missing: Topics without descriptions cannot be published and must be edited in the Publish step or Virtual Agent Designer.

    What to Expect

    ServiceNow customers migrating from NLU to LLM can expect a detailed migration log that helps identify and resolve issues efficiently. Most issues related to content generation or script conversion require manual review or editing to ensure quality and functionality post-migration. Critical process failures require support from ServiceNow. This structured approach ensures a smoother transition to LLM topics while maintaining topic integrity and publish readiness.

    The Topic Migration Execution Items [topic_migration_execution_item.list] table includes data when migrating Natural Language Understanding (NLU) topics to large language model (LLM) topics such as the migration status, migration issues, and migrated or published topic information.

    You can access this topic migration data either by searching for topic_migration_execution_item.list in the Navigation pane or downloading the .CSV file version of the table. After you've migrated topics, the downloadable .CSV file is accessible through the Review migration log option in the topic migration workflow's Migrate topics step.

    Figure 1. Example of the Review migration log option
    Review migration log is an option available after topic migration is complete that appears in relation to the Migration progression status bar.

    The Topic Migration Execution Items [topic_migration_execution_item.list] table defaults to include the following columns:

    • Description
    • Issues
    • LLM Topic
    • Migration Execution
      Note:
      The Migration Execution column includes the unique ID that is generated for each migration batch. For example, when 10 topics are migrated at the same time, the table contains 10 topic rows with each row containing the same migration execution value.
    • Migration status
    • NLU Topic
    • Status
    • Type
    Figure 2. Example of the Topic Migration Execution Items table data
    Topic migration execution items log example with the following default columns: Description, Issues, LLM Topic, Migration Execution, Migration status, NLU Topic, Status, and Type.

    Generic issues may occur during the topic migration process. The following table includes specific, common issues that you may encounter in the Issues column and whether the issue blocks the topic from being published.

    Table 1. Issues column details
    Issues column value Types of issues Can the topic be published?
    Some topic properties couldn’t be generated. To publish, manually review and edit the following nodes: [list of node names] Node-level issues: These issues are validation error messages that can include missing fields such as name, description, and so on. No.

    The issue must be corrected before the topic can be published.
    Some topic properties couldn’t be generated because the topic used a script. To publish, manually review and edit the following nodes: [list of node names] Script-level issues: These issues occur whenever an NLU input node has a script or data pill in the Prompt field. Yes.

    Topics with this issue can be published because Collect [Node Name] populates in the Detailed description field, but the value of the Detailed description field value should be revised and improved.
    Some topic properties couldn't be generated. Edit them before publishing the topic. Topic-level issues: These issues are validation errors at the topic level such as a missing description, keywords, or any other required field. No.

    The issue must be corrected before the topic can be published.
    The topic description couldn’t be generated. Edit the description field on the Publish page or from the topic properties page in Virtual Agent Designer before publishing. LLM-generated description issues: These issues occur whenever LLM is unable to generate a valid topic description. Yes.

    Topics with this issue can be published because the [Topic name] populates the Topic description field, but the Topic description field value should be revised and improved.
    The topic description couldn’t be generated because the mapped intent wasn’t found. Edit the description field on the Publish page or from the topic properties page in Virtual Agent Designer before publishing. LLM-generated description issues related to NLU intent complications: These issues occur whenever an NLU model and intent is mapped to a topic but is missing from the sys_nlu_model or sys_nlu_intent table or if these values are incorrectly mapped to the topic. Yes.

    Topics with this issue can be published because the [Topic name] populates the Topic description field, but the Topic description field value should be revised and improved.
    The topic description couldn’t be generated because both the intent and keywords are missing. Edit the description field on the Publish page or from the topic properties page in Virtual Agent Designer before publishing. LLM-generated description issues related to NLU intent complications: These issues occur whenever an NLU model's intent and keywords aren’t mapped to the topic. Yes.

    Topics with this issue can be published because the [Topic name] populates the Topic description field, but the Topic description field value should be revised and improved.
    The migration tool couldn’t convert one or more dynamic topic block nodes from this topic. The topic blocks used inside the dynamic topic blocks must be manually migrated. The following nodes use these dynamic topic blocks: [list of node names] Dynamic topic block issues: These issues occur whenever there’s a node that has a dynamic topic block that wasn’t migrated. Yes.

    Topics with this issue can be published because the topic block names use a script for dynamic topic blocks and continue to operate as expected, using the NLU topic block. If you encounter this issue, select these topic blocks for migration from the Select topics step and update the topic block names in the script.
    The migration tool couldn’t convert one or more switch topic scripts from this topic. The topics used inside the switch topic script need to be manually migrated. The following nodes use these switch topic scripts: [list of node names] Switch topic script issues: These issues occur whenever a node has a switch topic function that wasn’t migrated. Yes.

    Topics with this issue can be published because the topic script continues to use the NLU topic until migration. If you encounter this issue, select these topics for migration from the Select topics step.
    This topic couldn't be migrated. Contact ServiceNow support for assistance. Process failure issues: These issues occur whenever there's an error during a particular migration process. No.

    The issue must be corrected by a ServiceNow employee before the topic can be published.
    This topic couldn't be migrated because the transformation of NLU nodes to LLM nodes failed. Contact ServiceNow support for assistance. Process failure issues: These issues occur whenever there's an error during the transformation of NLU nodes to LLM nodes. No.

    The issue must be corrected by a ServiceNow employee before the topic can be published.
    This topic couldn't be migrated because the publish payload failed to generate. Contact ServiceNow support for assistance. Process failure issues: These issues occur whenever there's an error during a particular migration process. No.

    The issue must be corrected by a ServiceNow employee before the topic can be published.
    This topic can’t be published until a topic description is added. Process failure issues: These issues occur whenever there's an error during a particular migration process. No.

    The issue must be corrected before the topic can be published. Edit the description field on the Publish step or from the topic properties page in Virtual Agent Designer before publishing.