Author and run Atheris - Google's Python coverage-guided fuzzer built on libFuzzer. Covers pip installation, atheris.Setup + atheris.Fuzz invocation, TestOneInput(data: bytes) target signature, FuzzedDataProvider for structured input, instrument_imports() / instrument_func decorators for coverage instrumentation, and libFuzzer-passthrough flags (-atheris_runs, -max_total_time, -dict). Use for fuzzing Python libraries - also supports CPython native-extension fuzzing.