Overview

Record step-by-step EVM execution with opcode, call, and pre-state tracers.

mega-evme can record detailed execution traces during EVM runs. Traces are useful for debugging reverts, analyzing gas consumption, and understanding call flow.

Enabling Tracing

Add --trace to any command to enable tracing:

mega-evme run 0x60016000526001601ff3 --trace

By default, this uses the opcode tracer. Use --tracer to pick a different tracer.

Tracers

Tracer	--tracer value	Description
Opcode	opcode (default)	Step-by-step opcode execution log with gas, stack, memory, and storage
Call	call	Nested call tree showing CALL/CREATE hierarchy, gas, and return data
Pre-State	pre-state (alias: prestate)	Account state accessed during execution, with optional diff mode

Common Options

These flags apply to all tracers:

Flag	Default	Description
--trace	false	Enable tracing
--trace.output <PATH>	stdout	Write trace output to a file instead of the console
--tracer <TRACER>	opcode	Select which tracer to use

Output

Trace output is JSON. When --trace.output is not set, the trace is printed to stdout after the execution result. When --trace.output is set, the trace is written to the specified file and only the execution result appears on stdout.

# Trace to file
mega-evme run 0x60016000526001601ff3 \
  --trace --tracer opcode \
  --trace.output trace.json

# Trace to stdout (default)
mega-evme run 0x60016000526001601ff3 --trace