Extract business rules

This page provides instructions on how to use the business rules extraction in Mainframe Assessment Tool to help you validate existing business logic and identify obsolete rules in your mainframe codebase. You can extract business rules from applications written in PL/I, COBOL, and JCL.

During business rule extraction, Mainframe Assessment Tool analyzes your mainframe application codebase to identify the business rules, and presents them in a standardized, human-readable format.

Benefits of business rules extraction

Business rules extraction helps you achieve the following goals:

  • Create a single source of truth: Mainframe Assessment Tool extracts your mainframe application logic into human-readable business rules in Gherkin, a plain-text domain-specific language (DSL) used in behavior-driven development (BDD). This standardized format translates complex code into clear scenarios, bridging the gap between technical discovery and business intent.
  • Eliminate obsolete logic: identify and remove irrelevant rules to streamline the migration to Google Cloud.
  • Accelerate modernization: generate application specifications from your mainframe code to speed up the modernization process.
  • Reduce risk: minimize functional divergence by validating the extracted rules with business process owners before modernization.

This page is intended for mainframe developers, enterprise architects, and business analysts who want to understand and modernize legacy mainframe applications by extracting business rules from source code.

This page explains how to do the following:

  • Extract business rules: run an extraction job to identify business rules in your mainframe application.
  • Review and validate rules: analyze the extracted rules to ensure accuracy and relevance to your modernization goals.
  • Update rule status: update the status of the extracted rules to reflect their relevance to your modernization goals.
  • Export business rules: export the extracted rules to a file for further analysis or modernization.

Before you begin

Before you begin, make sure that you have completed the following tasks:

  • Create an assessment: make sure that you have an existing assessment with uploaded mainframe assets such as programs and copybooks. For more information, see Create an assessment.

  • Identify the entry point: select the primary module in your mainframe application that serves as the entry point for business rules extraction.

Start a business rules extraction job

Mainframe Assessment Tool uses Gemini-powered agents to analyze your code. These agents perform the extraction in several steps, such as parsing code, identifying decision logic, and generating natural language output.

You can run multiple extraction jobs within a single assessment to analyze large applications incrementally. This process lets you focus on specific business functions such as invoicing or payroll by selecting different sets of assets for each job. Each time you start a new extraction, you can select a different set of assets for analysis.

To start a business rules extraction job, follow these steps:

  1. Open the Mainframe Assessment Tool in a web browser.
  2. In the navigation menu, click Assessments.
  3. On the Assessments page, to open a specific assessment, click the expander arrow.
  4. Click Business rules.
  5. Click New extraction job.

  6. To configure the details of the extraction job, on the Basic information page, follow these steps:

    1. For Name, enter a unique identifier for the job.
    2. Optional: For Description, enter a short description of the job (up to 128 characters).
    3. Optional: For Focus prompt, provide specific instructions to focus the extraction. For example:
      • Extract only the tax calculation logic
      • Extract only rules involving the accounts data
      • Extract only rules that are implemented in the branch of the code that handles car insurance
    4. Click Next.

  7. From the Module list, select the primary module to analyze. You can only select one primary module.

    This module serves as the entry point for the extraction. When you select a primary module, Mainframe Assessment Tool automatically identifies and includes all dependencies, such as copybooks and called programs. This ensures that the business rules are complete and reflect the full application logic.

  8. Once you've selected the primary module, click Run extraction job.

While a job is running, the Extraction jobs table shows you the status of the job. This status indicates the number of internal planning steps that the agent has successfully completed out of the total required for that specific analysis.

After the extraction job finishes, the status in the Extraction jobs table changes to Completed.

Review the business rules

After Mainframe Assessment Tool extracts business rules, you can review and refine them. This review process ensures that only correct and necessary rules are used for modernization, and helps you identify obsolete or incorrect logic before the rules are modernized.

To review business rules in an extraction job, follow these steps:

  1. In the Extraction jobs table, select the job you want to review.

    The job overview displays the configuration details, such as the description, the focus prompt, and the list of assets included in the analysis. You also see a table with the extracted business rules and their associated tags.

  2. Review the list of extracted business rules and their associated tags.

  3. To open the Rule details pane, select a specific rule.

    The Rule details pane shows you the following information:

    • Summary: provides a description of the rule to let you understand the purpose and function of the rule.
    • Tags: displays the tags that Mainframe Assessment Tool automatically assigns to the rule. Use tags to understand the rule's context and filter the rules table for a specific mainframe application context.
    • Rule content: shows you the details of the business rule such as input data, output data, business logic, and edge cases.
    • Assets: lists the source code assets associated with the business rule that let you trace the rule back to the mainframe code.

Update rule status

When business rules are extracted, they are assigned an initial status of Awaiting review. During your review, you must validate these rules to make sure that they reflect the current business intent and identify rules that should be considered for modernization. By selecting a status, you make sure that the modernization specifications accurately reflect your current business needs.

To select the status of business rules, follow these steps:

  1. In the Business rules table, select the rules that you want to update.

  2. Click the Change status menu and then select one of the following statuses:

    • Awaiting review: the default status for all rules. It indicates that you have not yet reviewed the rule.
    • Validated: select this status to confirm that the rule is accurate and active. Mainframe Assessment Tool uses rules that you mark as Validated to regenerate application specifications for modernization.
    • Pending validation: select this status if you need to do further analysis or need inputs to validate the rule.
    • Obsolete: select this status to flag rules that are no longer relevant. Mainframe Assessment Tool excludes rules marked as Obsolete from export and modernization.

Export business rules

After you review the extracted business rules, you can export them to a file. Exporting business rules lets you use the rules as input with tools such as Gemini CLI for modernization and analysis, share them with stakeholders, or perform offline analysis.

To export business rules, follow these steps:

  1. In the Business rules table, select the rules that you want to export.
  2. To export business rules in JSON format, click Export.
  3. To export the agent configuration in Markdown for use with Gemini CLI, click Export for Gemini Modernization. This configuration lets Gemini CLI connect and directly download the rules.

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