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The Jolt CLI is the primary tool for working with the Jolt zkVM. It provides commands for creating projects, building guest programs, and running binaries on the Jolt emulator.

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Installation

Install the Jolt CLI using cargo: 
cargo +nightly install --git https://github.com/a16z/jolt --force --bins jolt
Verify the installation: 
jolt --version

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Available Commands

The Jolt CLI provides the following commands:
CommandDescription
jolt newCreates a new Jolt project with the specified name
jolt buildBuild a guest program for Jolt zkVM
jolt runRun an ELF binary on the Jolt emulator
jolt generateGenerate target specs or linker scripts
jolt build-wasmHandles preprocessing and generates WASM compatible files

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Common Workflows

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Creating a New Project

Start by creating a new Jolt project: 
jolt new my-project
cd my-project
This creates a workspace with:
  • Host code in src/
  • Guest code in guest/src/
  • Pre-configured Cargo.toml files
  • Rust toolchain configuration

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Building Guest Programs

Build your guest program for the Jolt zkVM: 
jolt build
For release builds with optimizations: 
jolt build --release

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Running on the Emulator

Execute a compiled guest binary on the Jolt emulator: 
jolt run target/riscv-guest/riscv64imac-unknown-none-elf/release/guest

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Environment Variables

The CLI respects several environment variables for configuration:

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Build Configuration

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JOLT_GUEST_OPT
string
default:"3"
Controls the optimization level for guest builds. Valid values: 0, 1, 2, 3, s, z.
JOLT_GUEST_OPT=s jolt build
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JOLT_BACKTRACE
string
Enables backtrace support for guest panics. Preserves symbols in the ELF for debugging.
  • 1 - Enable backtraces with function names and file:line info
  • full - Include register snapshots and cycle counts per frame
JOLT_BACKTRACE=1 cargo run --release

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Emulator Configuration

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JOLT_EMU_PATH
path
Path to the jolt-emu binary. If not set, the CLI searches PATH and common locations.
export JOLT_EMU_PATH=/usr/local/bin/jolt-emu
jolt run guest.elf

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Logging

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RUST_LOG
string
Controls log level output. Set to info, debug, or trace for more verbose output.
RUST_LOG=info jolt build

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Target Architecture

Jolt targets RISC-V 64-bit with the following extensions:
  • RV64I - Base Integer Instruction Set
  • M - Integer Multiplication and Division
  • A - Atomic Instructions
  • C - Compressed Instructions
The default target triple is riscv64imac-unknown-none-elf for no_std guests.

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Build Modes

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No-std Mode (Default)

Builds guest programs without the Rust standard library: 
jolt build
Target: riscv64imac-unknown-none-elf

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Std Mode

Builds with standard library support using musl libc: 
jolt build --std
Target: riscv64imac-zero-linux-musl This mode automatically installs or builds the required toolchain components (musl, gcc libs) if not already present.

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Next Steps

jolt new

Create new Jolt projects

jolt build

Build guest programs with all options

jolt run

Run binaries on the emulator

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