euler

Euler is an open-source research agent (with coding capabilities) and a runtime-extensible platform designed for building agent workflows. Its small core acts as scaffolding that extensions can extend with commands, context slots, artifacts, checkpoints, typed plan presentation, capabilities, and companion-agent patterns without modifying the core. Key features include: - **First-class provenance:** An append-only event log captures every model call, tool invocation, permission decision, and reasoning artifact at provider fidelity. The philosophy is that narration is not evidence; artifacts are. - **Clean canvas, durable memory:** Context stays focused while the event record remains intact. Under budget pressure, content may degrade to compact stubs, but facts about what happened are never silently lost. - **Runtime-extensible core:** A small provenance-bearing core powers extensions via `euler-sdk`. Euler ships core-only; extensions are linked or installed packages. First-party extensions include session-export, code-swarm, diagnostics-report, autoresearch, and maxproof. - **Multi-model, multi-agent, trust-aware:** Supports OpenAI, Anthropic, and OpenRouter, with companion agents spawned inside sessions. Local-first by default: the OS account is the trust boundary, secrets are tainted and redacted, every permission decision is logged, and failures are verbose rather than silent. - **Causal DAG:** The signature extension renders sessions as a branching tree of attempts (open, blocked, inconclusive, successful, verified, dead end, superseded, or abandoned), queryable by both users and the agent itself, so runs compound instead of restarting. - **Sandboxed execution:** Shell and Git tools run inside an enforced sandbox by default using Bubblewrap on Linux and Seatbelt on macOS. If the required backend cannot be applied, tools fail closed rather than running unconfined. - **Interactive TUI and headless modes:** The TUI provides slash commands for models, sessions, and extensions. Headless execution supports bounded rounds, auto-approval policies, and provenance logging. - **Extension system:** Packages can be validated, linked, installed, searched, and audited. Managed-process packages run through a language-neutral JSON-RPC stdio runtime. Python is the first SDK, with Rust also supported via euler-sdk traits. - **Authentication:** Supports ChatGPT subscription via OAuth device flow, and API keys for Anthropic, OpenAI, and OpenRouter. Custom OpenAI-compatible endpoints can be added, including local models behind ollama or vLLM. Built in Rust (1.80+ recommended), Euler runs on Linux and macOS. Prebuilt binaries are available for Linux x86_64/aarch64 and macOS Intel/Apple Silicon. The project is licensed under MIT and is currently at v0.1.0.