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>log in to commentI'm building Arxo so applications and AI agents can run models of rules instead of re-deriving them each time. A model is a versioned dependency: typed rules, pinned source text, dates and imports. Give it facts and a closed question; it returns the answer with its derivation and the source anchors, and it says when a judgment belongs to a court or an arbiter. The public repositories are demonstrations across law, chess, physics, chemistry, biology and philosophy. Fastest start: the chess package on npm, or npm start in github.com/arxohq/law. I'd like to hear where this would fit into your stack.
- Executable knowledge infrastructure for laws, standards, textbooks
- Google sign‑in for community access
- Model any authoritative text with provable calculations
- Shared, versioned canon that can be reused across applications
- Open‑source extensions like Arxo Law for VS Code
Arxo turns laws, standards and textbooks into reusable executable models with verifiable grounds.
- for
- Developers building apps or AI agents that need reproducible legal or policy reasoning.
- license
- Apache-2.0
Key features
- Versioned knowledge models — Pin a specific edition of a law or standard and get consistent results.
- Grounds inspection — Returned answers include the rules applied, premises and source text.
- Four truth states — Results are classified as established, refuted, conflicting, or not established.
- SDK & CLI integration — Use the @arxo/law npm package, @arxo/cli, or a local MCP server to query models.
- Multi-domain coverage — Models exist for law, standards, clinical scores, science, games and more.
- Reproducible answers — Same facts and edition always produce the same result with full audit trail.
Use cases
- Calculate EU flight compensation based on Regulation 261 using factual flight data.
- Determine tax liability by feeding transaction facts into a tax code model.
- Validate clinical scores (e.g., CHA₂DS₂-VASc) for patient data with traceable rule sources.
- Check compliance of a software component against ISO or IEC standards.
Arxo vs alternatives
 Arxo |  LangChain |  LlamaIndex |  LangGraph |  Devin | |
|---|---|---|---|---|---|
| Best for | Executable legal and policy models | LLM app framework | Data indexing for LLMs | Stateful agent orchestration | Autonomous AI software engineering |
| Pricing | Free | Free | Free | Free | Subscription |
| DevHunt upvotes | 1 | 0 | 0 | 0 | 0 |
| Launched | Oct 2026 | — | — | — | — |
- Arxo vs LangChain: LangChain focuses on building LLM apps over unstructured data, not on executable legal models.
- Arxo vs LlamaIndex: LlamaIndex indexes data for retrieval, whereas Arxo provides rule-based reasoning with verifiable grounds.
- Arxo vs LangGraph: LangGraph manages stateful AI agents, while Arxo models static legal knowledge for deterministic answers.
- Arxo vs Devin: Devin builds autonomous AI engineers; Arxo supplies deterministic rule execution for legal/policy domains.
Arxo FAQ
How does Arxo return the reasoning behind an answer?+
The SDK returns the result together with the specific provisions, passages and edition that were applied.
Can I use my own rule set or policy with Arxo?+
Yes, you can turn any rule, standard or policy into a knowledge model and query it via the SDK or CLI.
What truth states does Arxo distinguish?+
Arxo classifies outcomes as established, refuted, conflicting, or not established.
Is the model versioned?+
Each model is tied to a specific source edition, so changes in the source or facts can be replayed against the original version.
What platforms can I call Arxo from?+
Arxo provides an npm package, a CLI tool, and generated code for multiple target languages.
Summarized by DevHunt from arxo.io · Oct 14, 2026. Details may change; check the official site.
