Give form to your harness

Define, test, evolve, and share your harness as code, with agents, skills, and evals in one structured system.

Get started Try the playground
npx atlante@latest init

Capabilities

  • Compose reusable presets and templates for agents and skills.
  • Build deterministic OpenCode-native files with atlante build.
  • Evaluate harnesses in OpenCode with versioned scenarios and atlante eval.
  • Initialize projects from shared harness packs with atlante init --pack <your-pack>.

Boundaries

  • No LLM inference or agent/skill execution.
  • No project-code execution.
  • No model, effort, permission, tool, or mode selection.
  • No runtime-state, checkpoint, or scheduling management.
  • OpenCode is the only supported host for now.

The celestial sphere of harnesses

Follow the hierarchy from individual agents to complete, versioned harness families.

An agent is a star

Define each role with a clear identity, mission, and instructions.

Stars form constellations

Combine complementary roles around the work they share.

Constellations form families

A family is one project's complete harness: its agents, skills, values, evals, and host configuration.

Families have specific coordinates

Atlante validates its source and materializes deterministic, host-native files.

Families form the celestial sphere

Each family stays independently authored and versioned within one coherent system.

Explore Atlante

Edit the configuration, build it, and inspect the generated files.

Playground

Source atlante.jsonc
{ "$schema": "https://atlante.sh/schema/v0.1/schema.json", "values": { "project": "NEXORA", "apiTestCommand": "bun run test:api" }, "agents": { "api-reviewer": { "$template": "@atlante/pack/agent", "description": "Use when reviewing a public API surface for consistency, compatibility, and clear request and response contracts before changes merge.", "identity": "You are the API reviewer for {{values.project}}, responsible for keeping its public surface small, coherent, and safe to evolve.", "mission": "You are responsible for reviewing API changes with the smallest process that produces a clear, compatible, and verified contract.", "sections": [ { "instructions": [ "Read the existing public API and its tests before proposing a change", "Define request, response, and error contracts explicitly for every endpoint", "Keep naming, versioning, validation, and compatibility consistent with the existing API", "Run {{values.apiTestCommand}} after changing the API and report the result" ] }, { "invariants": [ "Public API changes MUST preserve backward compatibility unless a breaking change is explicitly approved", "Every new endpoint MUST define request, response, and error behavior", "API changes MUST include or update focused tests", "The public API MUST NOT expose internal implementation details" ] } ] } }, "skills": { "review": "@atlante/pack/review" }, "eval": { "host": "opencode", "scenarios": "eval/scenarios/reviews-public-api.eval.json" } }
Generated Build to inspect 
Press Build to inspect generated native files.

Build validates the configuration and materializes native files in an isolated sandbox. 

$ npx atlante@latest build

Harnesses in practice

Apply one versioned harness across reviews, projects, and evaluations.

Keep review rules consistent

Define a no-secrets policy once, reuse it across review agents, and validate every binding before you build.

Give every project the same starting point

Package your team's agents, skills, values, and policies once, then initialize new repositories from the reviewed pack.

Catch breakage before sharing

Run a scenario through OpenCode in a sandbox, grade deterministic checks, and catch regressions before sharing.

Build your harness

Follow the getting started guide, or explore the source on GitHub.

Get started View on GitHub