Isaac is an ACP-compliant coding agent and reference CLI client.

• Agent implementation: isaac.agent
• Client REPL implementation: isaac.client
• Protocol: Agent Client Protocol (ACP)

Since Newton discovered gravity, everything's been going downhill.

pip install isaac-acp

Run the agent:

isaac

Run the bundled client against the bundled agent:

python -m isaac.client isaac

Or when developing from source:

uv run python -m isaac.client uv run isaac

Isaac loads environment variables from:

1. <platform config dir>/isaac/.env (via platformdirs; Linux example: ~/.config/isaac/.env)

Common variables:

• OPENROUTER_API_KEY (or provider-specific model keys)
• ISAAC_ACP_STDIO_BUFFER_LIMIT_BYTES (optional ACP stdio buffer override)

• ACP 0.8 session config options for mode/model selection
• Prompt turns, tool calls, filesystem and terminal ACP flows
• Interactive client slash commands (/mode, /model, /status, /usage)
• MCP server config forwarding from the client to the agent

uv pip install -e .
uv run ruff format .
uv run ruff check .
uv run mypy src tests
uv run pytest
uv build --wheel --sdist