List of arbitrary text tags. Tags may be any valid string; default is the empty list.

Tags can be used on any rule. Tags on test and test_suite rules are useful for categorizing the tests. Tags on non-test rules are used to control sandboxed execution of genrules and [Skylark](/docs/skylark/index.html) actions, and for parsing by humans and/or external tools.

Bazel modifies the behavior of its sandboxing code if it finds the following keywords in the tags attribute of any test rule or genrule, or the keys of execution_requirements for any Skylark action.

• local keyword results in the action or test never being run remotely or inside the [sandbox](/docs/bazel-user-manual.html#sandboxing). For genrules and tests, marking the rule with the local=1 attribute has the same effect.
• requires-network keyword allows access to the external network from inside the sandbox.

Tags on tests are generally used to annotate a test's role in your debug and release process. Typically, tags are most useful for C++ and Python tests, which lack any runtime annotation ability. The use of tags and size elements gives flexibility in assembling suites of tests based around codebase check-in policy.

Bazel modifies test running behavior if it finds the following keywords in the tags attribute of the test rule:

• exclusive keyword will force test to be run in the "exclusive" mode, ensuring that no other tests are running at the same time. Such tests will be executed in serial fashion after all build activity and non-exclusive tests have been completed. They will also always run locally and thus without sandboxing.
• manual keyword will force test to be ignored by all command line wildcards (..., :*, :all, etc). It will also be ignored by the test_suite rules that do not mention this test explicitly. The only way to run such test is to specify it explicitly on the command line.
• external keyword will force test to be unconditionally executed (regardless of --cache_test_results value).