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Modify the application library

If you are deploying the Chrome OS Readiness Tool, you can add additional application classification data by modifying the application library.

What is the application library

The Chrome OS Readiness Tool uses a JSON application library to determine if the devices are ready for Chrome OS deployment. How applications are classified is detailed in the table below.

Process type Description Examples Impact on device classification


Members of the ready array in a library file

Applications with direct equivalents or comparable functionality on Chrome OS Browsers, system utilities, applications with web versions Presence of only Ready application usage make devices ideal switching candidates

Possibly Ready

Members of the possibly_ready array in a library file

Applications with Chrome OS equivalents, depending on use case and needs Email clients, VoIP, word processing, and other applications that might have more complex usage Any Possibly Ready applications might require workarounds or additional attention


Members of the blockers array in a library file

Full applications that Chrome OS doesn’t natively support without virtualization, as well as applications with Windows needs specific to the domain Applications that are required to run on Windows in your domain or generally, such as legacy software Usage of these applications at any point in assessment will flag a device as not suitable for switching unless you perform virtualization solutions

What are the base library and edit set

The library is used when the clients generate their reports. There are two components of the library:

  • The base library—Part of the bundle .msi and, most importantly, cannot be changed for a version. A reference file is included in the shared folder, and can also be found in c:\ProgramData\Google\Chrome OS Readiness\base_library.json.
  • (Optional) The edit set—A .json file in roughly the same format as base_library.json that can contain additions to the library or overwrite entries, to leverage the local admin’s domain knowledge. Everything in this file has priority over the base library. It is saved in the configured shared folder, and must be named edit_set.json. You can see examples of edit sets in the library/ folder in the bundle. For details, see Download the tool software bundle.

When the client generates a report both of these libraries are merged.

Modifying the application library

To modify the classifications, or add new classifications based on your domain and usage, you can prepare an edit set that the tool references alongside base_library.json.

Important: Do not edit base_library.json itself.

If there are overlapping classifications between the two files, your provided classification in edit_set.json is the one the tool uses. To prepare edit_set.json, do the following:

  1. Copy empty_edit_set.json from the bundle library directory into the configuration folder you used the in the setup.
  2. Rename it edit_set.json.
  3. Add the executable name for the applications for which you want to overwrite the classification in the base library, or for those that are not in the base library that you want to add.
  4. To check your edit set JSON file for formatting and make sure there are no conflicts, you can run the Helper Tool.
  5. You can use the version field to mark this edit set with a version. This field must only contain numbers and dots as separators. Examples of valid versions: 1, 2.1, 1.2.3.

We recommend adding as much additional information as you have available. Classifying additional applications as Ready helps maximize the number of devices that are ready to switch. Adding blockers specific to your domain ensures that you can easily see which devices need attention.

Any additional information helps us improve our library. Please consider sending us your edit set modifications.

Additional information

Preliminary vs. final results and mid-trial adjustments

When the service is configured and deployed to a client, it begins to collect data and generates a report based on this configuration. This report is saved as a result file HOST_NAME.json in the configured results folder.

While the trial is running, you can still make library adjustments, even when only partial results, results from a subset of client devices, are available. The client result files contain a line analysis_result: with the value RED, YELLOW, or GREEN. This is a preliminary result based on the knowledge the client had when generating the report. A final result is generated when you run the Chrome OS Readiness Helper Tool to generate a summary for the whole domain. The service on the client machines uses whatever version of edit_set.json it finds when the assessment ends.

If you want to classify an application differently, or have additional applications that would be relevant to classify, you can make that modification without starting an assessment from the beginning. You can modify and validate edit_set.json as above if needed.

Unknown applications

Over the course of an assessment, the tool collects instances of new applications not in the provided library, labeled as Unknown.

We recommend classifying as many of these as possible as Ready or Blocker applications. The Helper Tool used to generate reports can list these applications for you to classify, as well as validate edit set format. For details, see Generate reports.

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