rho-agent-0.3.0 is not a library.

rho

A fast, extensible AI coding agent built in Rust. Rho gives an LLM a set of developer tools — file editing, shell access, web search, sub-agents — and runs an autonomous loop to complete coding tasks.

Features

Multi-provider support — Anthropic Claude, xAI Grok, and any OpenAI-compatible API (Groq, Ollama, etc.)
Rich tool set — Read/write/edit files, run shell commands, regex search, glob find, web fetch & search, sub-agent tasks
LINE:HASH editing — Hash-based line anchoring for precise, resilient file edits
Session persistence — SQLite-backed sessions with full history and resume support
Autonomous loop — Plan and build modes for hands-off multi-step execution
Extended thinking — First-class support for reasoning models (Claude Opus, Grok reasoning)
Project config — Per-project settings via RHO.md or CLAUDE.md with YAML frontmatter
Post-tool hooks — Run validation commands (tests, lints) automatically after tool use
Skills & commands — Auto-discover project-specific skills and slash commands
Streaming output — Text or JSON streaming for integration with other tools

Installation

From source

git clone https://github.com/pyrex41/rho.git
cd rho
cargo install --path .

Pre-built binaries

Download from GitHub Releases. Binaries are available for:

Linux x86_64 / ARM64
macOS x86_64 / ARM64 (Apple Silicon)
Windows x86_64

Quick start

# Set your API key
export ANTHROPIC_API_KEY="sk-..."

# Run a one-shot prompt
rho-cli "add error handling to src/main.rs"

# Use a specific model
rho-cli --model claude-opus "refactor the auth module"

# Enable extended thinking
rho-cli --thinking high "design a caching layer"

# Resume a previous session interactively
rho-cli --resume <session-id>

Usage

rho-cli [OPTIONS] [PROMPT]
rho-cli loop [OPTIONS]

Options

Flag	Description	Default
`--model <ID>`	Model registry ID or raw model ID	`claude-sonnet`
`--thinking <LEVEL>`	Thinking level: off, minimal, low, medium, high	`off`
`--show-thinking`	Display thinking output on stderr
`--api-key <KEY>`	Override API key	env var / keychain
`-C, --directory <PATH>`	Working directory	current dir
`--prompt-file <FILE>`	Read prompt from file
`--resume <SESSION>`	Resume an existing session
`--tools <LIST>`	Restrict available tools (comma-separated)	all
`--system-append <TEXT>`	Append to the system prompt
`--output-format <FMT>`	`text` or `stream-json`	`text`

Autonomous loop

# Build mode — execute tasks from an implementation plan
rho-cli loop

# Plan mode — create or refine IMPLEMENTATION_PLAN.md
rho-cli loop --mode plan

# Custom plan file, more iterations
rho-cli loop --plan my-plan.md --max-iterations 100

Built-in tools

Tool	Description
`read`	Read files with `LINE:HASH` format, or list directories
`write`	Create or overwrite files
`edit`	Edit files using `LINE:HASH` anchors or text replacement
`bash`	Execute shell commands (PTY, up to 1 hour timeout)
`grep`	Search file contents with regex (respects `.gitignore`)
`find`	Find files by glob pattern (respects `.gitignore`)
`task`	Launch a sub-agent in a separate context
`web_fetch`	Fetch a URL and convert to markdown
`web_search`	Search the web via DuckDuckGo (no API key needed)

Supported models

Anthropic Claude

claude-sonnet — Claude Sonnet 4.5 (default)
claude-opus — Claude Opus 4.6 (with extended thinking)
claude-haiku — Claude Haiku 4.5

xAI Grok

grok-3, grok-3-mini, grok-2
grok-4.20-reasoning, grok-4.20-non-reasoning (experimental)

Custom models

Add models via ~/.rho/models.toml:

[[model]]
id = "gpt-4o"
provider = "openai"
model_id = "gpt-4o"
api_key_env = "OPENAI_API_KEY"
context_window = 128000
max_tokens = 16384
thinking = false

Configuration

Create a RHO.md (or CLAUDE.md) in your project root:

---
model: claude-sonnet
thinking: high
memories: true
compact_threshold: 0.7
validation_commands: ["cargo test", "cargo clippy"]
post_tools_hooks:
  - name: tests
    command: cargo test
    timeout: 60
    inject_on_failure: true
    trigger_tools: [write, edit]
---

Additional system prompt instructions go here as markdown.

Environment variables

Variable	Description
`ANTHROPIC_API_KEY`	Anthropic API key
`XAI_API_KEY`	xAI / Grok API key
`OPENAI_API_KEY`	OpenAI API key
`RHO_SESSION_DB`	Custom path for the session database
`RUST_LOG`	Tracing filter (default: `warn`)

Project structure

crates/
├── rho-core        # Agent loop, types, config, event system
├── rho-provider    # LLM provider implementations (Anthropic, OpenAI-compat)
├── rho-tools       # Built-in tool implementations
├── rho-session     # SQLite session persistence
├── rho-hashline    # LINE:HASH file anchoring
├── anthropic-auth  # OAuth PKCE + API key management
├── rho-gui         # GUI frontend (iced, in development)
├── rho-cli         # CLI crate stub
└── rho-lib         # Shared utilities
src/
├── main.rs         # CLI entry point
└── loop_runner.rs  # Autonomous loop logic

License

MIT

rho-agent 0.3.0

rho