Open source · Apache 2.0 · Built in Go · Star on GitHub →
106 tests passing · 11 tools · zero dependencies

Stop overpaying for AI agent decisions.

ARK routes each step to the right model, tracks cost per decision, and learns what works. Single Go binary. Open source.

Get Started See it work ↓
Works with OpenAI Anthropic Ollama
Real output from a live run
ARK cost report and model routing output
Capabilities

Everything an agent runtime needs.

ARK sits between your agent and the LLM provider. It optimizes every decision for cost, quality, and speed.

Per-step model routing

Tool calls go to cheap models. Reasoning goes to strong models. The router learns from failures and self-improves across runs.

💰 Cost per decision

Every step has a dollar amount. Cost feeds back into tool ranking — expensive unreliable tools get demoted automatically.

📉 99% less context waste

MCP servers dump 60K+ tokens into every prompt. ARK loads 3–5 relevant tools per task. Context goes to reasoning.

🧠 Persistent learning

Successful tools rise. Failing tools drop. Query patterns are remembered. Routing decisions persist across restarts.

🛡️ Grounding gate

When tools are available, the LLM cannot answer without using them. Zero hallucinated answers across 30 stress test runs.

🔌 Connect any API

Define HTTP tools in agent.yaml with ${ENV_VAR} support. ARK handles allowlisting, validation, and learning. No code.

106
Tests passing
11
Built-in tools
3
LLM providers
0
Dependencies
Before & After

What changes when you add ARK.

ARK doesn't replace your tools or your models. It makes every interaction between them more efficient.

Without ARKWith ARK
Context usage60,468 tokens on schemas~80 tokens (99.9% reduction)
Model selectionOne model for everythingRight model per step, learned
Cost visibilityMonthly API billPer-step, per-tool, per-action
Tool rankingManual, staticLearned from every execution
HallucinationLLM guesses without toolsGrounding gate enforced
SetupPython + SDKs + frameworksSingle Go binary, zero deps
Configuration

Three lines to enable routing.

Add a strategy to your agent.yaml. ARK handles everything else.

# agent.yaml model: provider: openai strategy: cost_optimized fast_model: gpt-4o-mini strong_model: gpt-4o

Try ARK in 30 seconds.

No API keys needed for demos. Clone, build, run.

$ git clone https://github.com/atripati/ark.git && cd ark && go run ./cmd/ark demo

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