Trace specification file

A trace specification file is a JSON file that can be passed to trace record to configure parameters of tracing. For those parameters that can be passed both on the command line and set in the specification file, the command line value overrides the one from the file.

The file supports the following top level-parameters:

  • app: string, url of the application to be run
  • args: array of strings, startup arguments to be passed to the application
  • categories: array of strings, tracing categories to be enabled
  • duration: integer, duration of tracing in seconds
  • measure: array of measurement specifications, see Benchmarking

For information about the Fuchsia tracing system, see Fuchsia tracing system.

For information on how to record a trace, see Recording a Fuchsia trace.


The tracing configuration is a JSON file consisting of a list of known category names and descriptions.

The format is as follows:

      "categories": {
        "category1": "description1",
        "category2": "description2"
      "providers": {
        "provider-label": "file:///provider-to-start-automatically"