Quick Start

This guide walks you through your first policy evaluation in under five minutes.

Prerequisites

• A tenant ID and API key issued by your Aster account administrator
• curl available on your system (or any HTTP client)

If you do not yet have a tenant ID, contact your administrator or refer to the tenant onboarding documentation.

Step 1 — Set Your Credentials

Export your credentials as environment variables so the examples below work without modification:

export ASTER_TENANT_ID="my-tenant"
export ASTER_API_SECRET="your-api-secret-here"

Step 2 — Evaluate a Simple Policy

The evaluate-source endpoint accepts a policy written directly in the request body. This is the fastest way to experiment without first creating a stored policy.

curl -X POST https://policy.aster-lang.dev/api/v1/policies/evaluate-source \
  -H "Content-Type: application/json" \
  -H "X-Tenant-Id: my-tenant" \
  -H "X-User-Role: MEMBER" \
  -d '{
    "source": "Module demo.\n\nRule greet given name as Text, produce Text:\n  Return \"Hello, \" + name + \"!\".",
    "context": {"name": "World"},
    "functionName": "greet",
    "locale": "en-US"
  }'

The source field contains the full Aster CNL policy. The policy above defines a single rule greet that accepts a name parameter and returns a greeting string. The context object supplies the input values.

Step 3 — Understand the Result

A successful evaluation returns HTTP 200 with a JSON body:

{
  "result": "Hello, World!",
  "error": null,
  "executionTimeMs": 12
}

Field	Type	Description
result	any	The value returned by the evaluated rule
error	string | null	Error message if evaluation failed; null on success
executionTimeMs	number	Wall-clock time taken to evaluate the policy, in milliseconds

If error is non-null, the result field will be null. See Error Handling for a full list of failure scenarios.

Step 4 — Try Batch Evaluation

When you need to evaluate the same policy against multiple input sets in a single network round-trip, use the evaluate-source-batch endpoint.

curl -X POST https://policy.aster-lang.dev/api/v1/policies/evaluate-source-batch \
  -H "Content-Type: application/json" \
  -H "X-Tenant-Id: my-tenant" \
  -H "X-User-Role: MEMBER" \
  -d '{
    "source": "Module demo.\n\nRule greet given name as Text, produce Text:\n  Return \"Hello, \" + name + \"!\".",
    "functionName": "greet",
    "locale": "en-US",
    "inputs": [
      {"name": "Alice"},
      {"name": "Bob"},
      {"name": "Carol"}
    ]
  }'

The response contains a results array with one entry per input, in the same order:

{
  "results": [
    {"result": "Hello, Alice!", "error": null, "executionTimeMs": 8},
    {"result": "Hello, Bob!",   "error": null, "executionTimeMs": 3},
    {"result": "Hello, Carol!", "error": null, "executionTimeMs": 3}
  ]
}

Individual items in the batch may fail independently. A non-null error on one item does not abort the remaining evaluations.

Next Steps

Now that you have a working evaluation, explore these topics to make the most of the API:

• Authentication — add HMAC signing to protect your requests
• Overview — understand the full capabilities of the policy engine
• Error Handling — handle failures gracefully in your application
• API Reference — complete reference for all endpoints and fields